Merge branch 'upstream-libuv' into update-libuv

* upstream-libuv:
  libuv 2020-09-22 (ed5b42d5)

48 files changed, 1594 insertions, 536 deletions

diff --git a/Utilities/cmlibuv/include/uv.h b/Utilities/cmlibuv/include/uv.h
index 6f32b48777..11891df8e2 100644
--- a/Utilities/cmlibuv/include/uv.h
+++ b/Utilities/cmlibuv/include/uv.h
@@ -251,7 +251,8 @@ typedef struct uv_utsname_s uv_utsname_t;
 typedef struct uv_statfs_s uv_statfs_t;
 
 typedef enum {
-  UV_LOOP_BLOCK_SIGNAL
+  UV_LOOP_BLOCK_SIGNAL = 0,
+  UV_METRICS_IDLE_TIME
 } uv_loop_option;
 
 typedef enum {
@@ -617,6 +618,12 @@ enum uv_udp_flags {
    * must not be freed by the recv_cb callback.
    */
   UV_UDP_MMSG_CHUNK = 8,
+  /*
+   * Indicates that the buffer provided has been fully utilized by recvmmsg and
+   * that it should now be freed by the recv_cb callback. When this flag is set
+   * in uv_udp_recv_cb, nread will always be 0 and addr will always be NULL.
+   */
+  UV_UDP_MMSG_FREE = 16,
 
   /*
    * Indicates that recvmmsg should be used, if available.
@@ -697,6 +704,7 @@ UV_EXTERN int uv_udp_try_send(uv_udp_t* handle,
 UV_EXTERN int uv_udp_recv_start(uv_udp_t* handle,
                                 uv_alloc_cb alloc_cb,
                                 uv_udp_recv_cb recv_cb);
+UV_EXTERN int uv_udp_using_recvmmsg(const uv_udp_t* handle);
 UV_EXTERN int uv_udp_recv_stop(uv_udp_t* handle);
 UV_EXTERN size_t uv_udp_get_send_queue_size(const uv_udp_t* handle);
 UV_EXTERN size_t uv_udp_get_send_queue_count(const uv_udp_t* handle);
@@ -867,6 +875,7 @@ UV_EXTERN int uv_timer_stop(uv_timer_t* handle);
 UV_EXTERN int uv_timer_again(uv_timer_t* handle);
 UV_EXTERN void uv_timer_set_repeat(uv_timer_t* handle, uint64_t repeat);
 UV_EXTERN uint64_t uv_timer_get_repeat(const uv_timer_t* handle);
+UV_EXTERN uint64_t uv_timer_get_due_in(const uv_timer_t* handle);
 
 
 /*
@@ -1208,12 +1217,12 @@ UV_EXTERN uv_pid_t uv_os_getppid(void);
 
 #if defined(__PASE__)
 /* On IBM i PASE, the highest process priority is -10 */
-# define UV_PRIORITY_LOW 39            // RUNPTY(99)
-# define UV_PRIORITY_BELOW_NORMAL 15   // RUNPTY(50)
-# define UV_PRIORITY_NORMAL 0          // RUNPTY(20)
-# define UV_PRIORITY_ABOVE_NORMAL -4   // RUNTY(12)
-# define UV_PRIORITY_HIGH -7           // RUNPTY(6)
-# define UV_PRIORITY_HIGHEST -10       // RUNPTY(1)
+# define UV_PRIORITY_LOW 39          /* RUNPTY(99) */
+# define UV_PRIORITY_BELOW_NORMAL 15 /* RUNPTY(50) */
+# define UV_PRIORITY_NORMAL 0        /* RUNPTY(20) */
+# define UV_PRIORITY_ABOVE_NORMAL -4 /* RUNTY(12) */
+# define UV_PRIORITY_HIGH -7         /* RUNPTY(6) */
+# define UV_PRIORITY_HIGHEST -10     /* RUNPTY(1) */
 #else
 # define UV_PRIORITY_LOW 19
 # define UV_PRIORITY_BELOW_NORMAL 10
@@ -1261,6 +1270,7 @@ UV_EXTERN int uv_os_gethostname(char* buffer, size_t* size);
 
 UV_EXTERN int uv_os_uname(uv_utsname_t* buffer);
 
+UV_EXTERN uint64_t uv_metrics_idle_time(uv_loop_t* loop);
 
 typedef enum {
   UV_FS_UNKNOWN = -1,
@@ -1792,9 +1802,11 @@ struct uv_loop_s {
   unsigned int active_handles;
   void* handle_queue[2];
   union {
-    void* unused[2];
+    void* unused;
     unsigned int count;
   } active_reqs;
+  /* Internal storage for future extensions. */
+  void* internal_fields;
   /* Internal flag to signal loop stop. */
   unsigned int stop_flag;
   UV_LOOP_PRIVATE_FIELDS
diff --git a/Utilities/cmlibuv/include/uv/errno.h b/Utilities/cmlibuv/include/uv/errno.h
index 165fd11c37..8d4d7686d2 100644
--- a/Utilities/cmlibuv/include/uv/errno.h
+++ b/Utilities/cmlibuv/include/uv/errno.h
@@ -317,7 +317,7 @@
 #if defined(EPROTO) && !defined(_WIN32)
 # define UV__EPROTO UV__ERR(EPROTO)
 #else
-# define UV__EPROTO UV__ERR(4046)
+# define UV__EPROTO UV__ERR(-4046)
 #endif
 
 #if defined(EPROTONOSUPPORT) && !defined(_WIN32)
diff --git a/Utilities/cmlibuv/include/uv/unix.h b/Utilities/cmlibuv/include/uv/unix.h
index f30562e622..a59192fa41 100644
--- a/Utilities/cmlibuv/include/uv/unix.h
+++ b/Utilities/cmlibuv/include/uv/unix.h
@@ -76,6 +76,8 @@
 # include "posix.h"
 #elif defined(__HAIKU__)
 # include "posix.h"
+#elif defined(__QNX__)
+# include "posix.h"
 #endif
 
 #ifndef NI_MAXHOST
diff --git a/Utilities/cmlibuv/include/uv/version.h b/Utilities/cmlibuv/include/uv/version.h
index f932483e4e..96c1c130f2 100644
--- a/Utilities/cmlibuv/include/uv/version.h
+++ b/Utilities/cmlibuv/include/uv/version.h
@@ -31,7 +31,7 @@
  */
 
 #define UV_VERSION_MAJOR 1
-#define UV_VERSION_MINOR 37
+#define UV_VERSION_MINOR 39
 #define UV_VERSION_PATCH 1
 #define UV_VERSION_IS_RELEASE 0
 #define UV_VERSION_SUFFIX "dev"
diff --git a/Utilities/cmlibuv/src/random.c b/Utilities/cmlibuv/src/random.c
index 491bf70330..e75f77deb2 100644
--- a/Utilities/cmlibuv/src/random.c
+++ b/Utilities/cmlibuv/src/random.c
@@ -33,7 +33,7 @@ static int uv__random(void* buf, size_t buflen) {
 
 #if defined(__PASE__)
   rc = uv__random_readpath("/dev/urandom", buf, buflen);
-#elif defined(_AIX)
+#elif defined(_AIX) || defined(__QNX__)
   rc = uv__random_readpath("/dev/random", buf, buflen);
 #elif defined(__APPLE__) || defined(__OpenBSD__) || \
      (defined(__ANDROID_API__) && __ANDROID_API__ >= 28)
diff --git a/Utilities/cmlibuv/src/strscpy.c b/Utilities/cmlibuv/src/strscpy.c
index 2a2bdce745..20df6fcbed 100644
--- a/Utilities/cmlibuv/src/strscpy.c
+++ b/Utilities/cmlibuv/src/strscpy.c
@@ -1,3 +1,24 @@
+/* Copyright libuv project contributors. All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
 #include "strscpy.h"
 #include <limits.h>  /* SSIZE_MAX */
 
diff --git a/Utilities/cmlibuv/src/strscpy.h b/Utilities/cmlibuv/src/strscpy.h
index fbe0a393f2..cc78149db5 100644
--- a/Utilities/cmlibuv/src/strscpy.h
+++ b/Utilities/cmlibuv/src/strscpy.h
@@ -1,3 +1,24 @@
+/* Copyright libuv project contributors. All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
 #ifndef UV_STRSCPY_H_
 #define UV_STRSCPY_H_
 
diff --git a/Utilities/cmlibuv/src/timer.c b/Utilities/cmlibuv/src/timer.c
index 4cf4ed4264..1bea2a8bd2 100644
--- a/Utilities/cmlibuv/src/timer.c
+++ b/Utilities/cmlibuv/src/timer.c
@@ -130,6 +130,14 @@ uint64_t uv_timer_get_repeat(const uv_timer_t* handle) {
 }
 
 
+uint64_t uv_timer_get_due_in(const uv_timer_t* handle) {
+  if (handle->loop->time >= handle->timeout)
+    return 0;
+
+  return handle->timeout - handle->loop->time;
+}
+
+
 int uv__next_timeout(const uv_loop_t* loop) {
   const struct heap_node* heap_node;
   const uv_timer_t* handle;
diff --git a/Utilities/cmlibuv/src/unix/aix-common.c b/Utilities/cmlibuv/src/unix/aix-common.c
index 44c87b10a0..5bd2a688e9 100644
--- a/Utilities/cmlibuv/src/unix/aix-common.c
+++ b/Utilities/cmlibuv/src/unix/aix-common.c
@@ -22,42 +22,23 @@
 #include "uv.h"
 #include "internal.h"
 
-#include <stdio.h>
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
-#include <assert.h>
-#include <errno.h>
 
 #include <sys/types.h>
-#include <sys/socket.h>
-#include <sys/ioctl.h>
-#include <net/if.h>
-#include <netinet/in.h>
-#include <netinet/in6_var.h>
-#include <arpa/inet.h>
 
 #include <sys/time.h>
 #include <unistd.h>
-#include <fcntl.h>
-#include <utmp.h>
-#include <libgen.h>
 
-#include <sys/protosw.h>
 #include <procinfo.h>
-#include <sys/proc.h>
-#include <sys/procfs.h>
 
-#include <sys/poll.h>
-
-#include <sys/pollset.h>
 #include <ctype.h>
 
-#include <sys/mntctl.h>
-#include <sys/vmount.h>
-#include <limits.h>
-#include <strings.h>
-#include <sys/vnode.h>
+extern char* original_exepath;
+extern uv_mutex_t process_title_mutex;
+extern uv_once_t process_title_mutex_once;
+extern void init_process_title_mutex_once(void);
 
 uint64_t uv__hrtime(uv_clocktype_t type) {
   uint64_t G = 1000000000;
@@ -78,81 +59,32 @@ uint64_t uv__hrtime(uv_clocktype_t type) {
  */
 int uv_exepath(char* buffer, size_t* size) {
   int res;
-  char args[PATH_MAX];
-  char abspath[PATH_MAX];
-  size_t abspath_size;
+  char args[UV__PATH_MAX];
+  size_t cached_len;
   struct procsinfo pi;
 
   if (buffer == NULL || size == NULL || *size == 0)
     return UV_EINVAL;
 
-  pi.pi_pid = getpid();
-  res = getargs(&pi, sizeof(pi), args, sizeof(args));
-  if (res < 0)
-    return UV_EINVAL;
-
-  /*
-   * Possibilities for args:
-   * i) an absolute path such as: /home/user/myprojects/nodejs/node
-   * ii) a relative path such as: ./node or ../myprojects/nodejs/node
-   * iii) a bare filename such as "node", after exporting PATH variable
-   *     to its location.
-   */
-
-  /* Case i) and ii) absolute or relative paths */
-  if (strchr(args, '/') != NULL) {
-    if (realpath(args, abspath) != abspath)
-      return UV__ERR(errno);
-
-    abspath_size = strlen(abspath);
-
+  uv_once(&process_title_mutex_once, init_process_title_mutex_once);
+  uv_mutex_lock(&process_title_mutex);
+  if (original_exepath != NULL) {
+    cached_len = strlen(original_exepath);
     *size -= 1;
-    if (*size > abspath_size)
-      *size = abspath_size;
-
-    memcpy(buffer, abspath, *size);
+    if (*size > cached_len)
+      *size = cached_len;
+    memcpy(buffer, original_exepath, *size);
     buffer[*size] = '\0';
-
+    uv_mutex_unlock(&process_title_mutex);
     return 0;
-  } else {
-    /* Case iii). Search PATH environment variable */
-    char trypath[PATH_MAX];
-    char *clonedpath = NULL;
-    char *token = NULL;
-    char *path = getenv("PATH");
-
-    if (path == NULL)
-      return UV_EINVAL;
-
-    clonedpath = uv__strdup(path);
-    if (clonedpath == NULL)
-      return UV_ENOMEM;
-
-    token = strtok(clonedpath, ":");
-    while (token != NULL) {
-      snprintf(trypath, sizeof(trypath) - 1, "%s/%s", token, args);
-      if (realpath(trypath, abspath) == abspath) {
-        /* Check the match is executable */
-        if (access(abspath, X_OK) == 0) {
-          abspath_size = strlen(abspath);
-
-          *size -= 1;
-          if (*size > abspath_size)
-            *size = abspath_size;
-
-          memcpy(buffer, abspath, *size);
-          buffer[*size] = '\0';
-
-          uv__free(clonedpath);
-          return 0;
-        }
-      }
-      token = strtok(NULL, ":");
-    }
-    uv__free(clonedpath);
+  }
+  uv_mutex_unlock(&process_title_mutex);
+  pi.pi_pid = getpid();
+  res = getargs(&pi, sizeof(pi), args, sizeof(args));
 
-    /* Out of tokens (path entries), and no match found */
+  if (res < 0)
     return UV_EINVAL;
-  }
+
+  return uv__search_path(args, buffer, size);
 }
 
diff --git a/Utilities/cmlibuv/src/unix/aix.c b/Utilities/cmlibuv/src/unix/aix.c
index 6b4594b43e..6a013d43e3 100644
--- a/Utilities/cmlibuv/src/unix/aix.c
+++ b/Utilities/cmlibuv/src/unix/aix.c
@@ -65,14 +65,15 @@
 #define RDWR_BUF_SIZE   4096
 #define EQ(a,b)         (strcmp(a,b) == 0)
 
-static uv_mutex_t process_title_mutex;
-static uv_once_t process_title_mutex_once = UV_ONCE_INIT;
+char* original_exepath = NULL;
+uv_mutex_t process_title_mutex;
+uv_once_t process_title_mutex_once = UV_ONCE_INIT;
 static void* args_mem = NULL;
 static char** process_argv = NULL;
 static int process_argc = 0;
 static char* process_title_ptr = NULL;
 
-static void init_process_title_mutex_once(void) {
+void init_process_title_mutex_once(void) {
   uv_mutex_init(&process_title_mutex);
 }
 
@@ -145,6 +146,8 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
   int i;
   int rc;
   int add_failed;
+  int user_timeout;
+  int reset_timeout;
 
   if (loop->nfds == 0) {
     assert(QUEUE_EMPTY(&loop->watcher_queue));
@@ -214,7 +217,21 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
   base = loop->time;
   count = 48; /* Benchmarks suggest this gives the best throughput. */
 
+  if (uv__get_internal_fields(loop)->flags & UV_METRICS_IDLE_TIME) {
+    reset_timeout = 1;
+    user_timeout = timeout;
+    timeout = 0;
+  } else {
+    reset_timeout = 0;
+  }
+
   for (;;) {
+    /* Only need to set the provider_entry_time if timeout != 0. The function
+     * will return early if the loop isn't configured with UV_METRICS_IDLE_TIME.
+     */
+    if (timeout != 0)
+      uv__metrics_set_provider_entry_time(loop);
+
     nfds = pollset_poll(loop->backend_fd,
                         events,
                         ARRAY_SIZE(events),
@@ -227,6 +244,15 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
     SAVE_ERRNO(uv__update_time(loop));
 
     if (nfds == 0) {
+      if (reset_timeout != 0) {
+        timeout = user_timeout;
+        reset_timeout = 0;
+        if (timeout == -1)
+          continue;
+        if (timeout > 0)
+          goto update_timeout;
+      }
+
       assert(timeout != -1);
       return;
     }
@@ -236,6 +262,11 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
         abort();
       }
 
+      if (reset_timeout != 0) {
+        timeout = user_timeout;
+        reset_timeout = 0;
+      }
+
       if (timeout == -1)
         continue;
 
@@ -280,16 +311,25 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
       /* Run signal watchers last.  This also affects child process watchers
        * because those are implemented in terms of signal watchers.
        */
-      if (w == &loop->signal_io_watcher)
+      if (w == &loop->signal_io_watcher) {
         have_signals = 1;
-      else
+      } else {
+        uv__metrics_update_idle_time(loop);
         w->cb(loop, w, pe->revents);
+      }
 
       nevents++;
     }
 
-    if (have_signals != 0)
+    if (reset_timeout != 0) {
+      timeout = user_timeout;
+      reset_timeout = 0;
+    }
+
+    if (have_signals != 0) {
+      uv__metrics_update_idle_time(loop);
       loop->signal_io_watcher.cb(loop, &loop->signal_io_watcher, POLLIN);
+    }
 
     loop->watchers[loop->nwatchers] = NULL;
     loop->watchers[loop->nwatchers + 1] = NULL;
@@ -830,6 +870,7 @@ void uv__fs_event_close(uv_fs_event_t* handle) {
 
 
 char** uv_setup_args(int argc, char** argv) {
+  char exepath[UV__PATH_MAX];
   char** new_argv;
   size_t size;
   char* s;
@@ -845,6 +886,15 @@ char** uv_setup_args(int argc, char** argv) {
   process_argv = argv;
   process_argc = argc;
 
+  /* Use argv[0] to determine value for uv_exepath(). */
+  size = sizeof(exepath);
+  if (uv__search_path(argv[0], exepath, &size) == 0) {
+    uv_once(&process_title_mutex_once, init_process_title_mutex_once);
+    uv_mutex_lock(&process_title_mutex); 
+    original_exepath = uv__strdup(exepath);
+    uv_mutex_unlock(&process_title_mutex);
+  }
+
   /* Calculate how much memory we need for the argv strings. */
   size = 0;
   for (i = 0; i < argc; i++)
@@ -875,6 +925,10 @@ char** uv_setup_args(int argc, char** argv) {
 int uv_set_process_title(const char* title) {
   char* new_title;
 
+  /* If uv_setup_args wasn't called or failed, we can't continue. */
+  if (process_argv == NULL || args_mem == NULL)
+    return UV_ENOBUFS;
+
   /* We cannot free this pointer when libuv shuts down,
    * the process may still be using it.
    */
@@ -908,6 +962,10 @@ int uv_get_process_title(char* buffer, size_t size) {
   if (buffer == NULL || size == 0)
     return UV_EINVAL;
 
+  /* If uv_setup_args wasn't called, we can't continue. */
+  if (process_argv == NULL)
+    return UV_ENOBUFS;
+
   uv_once(&process_title_mutex_once, init_process_title_mutex_once);
   uv_mutex_lock(&process_title_mutex);
 
diff --git a/Utilities/cmlibuv/src/unix/bsd-ifaddrs.c b/Utilities/cmlibuv/src/unix/bsd-ifaddrs.c
index a3385af17c..5223ab4879 100644
--- a/Utilities/cmlibuv/src/unix/bsd-ifaddrs.c
+++ b/Utilities/cmlibuv/src/unix/bsd-ifaddrs.c
@@ -113,7 +113,9 @@ int uv_interface_addresses(uv_interface_address_t** addresses, int* count) {
       address->address.address4 = *((struct sockaddr_in*) ent->ifa_addr);
     }
 
-    if (ent->ifa_netmask->sa_family == AF_INET6) {
+    if (ent->ifa_netmask == NULL) {
+      memset(&address->netmask, 0, sizeof(address->netmask));
+    } else if (ent->ifa_netmask->sa_family == AF_INET6) {
       address->netmask.netmask6 = *((struct sockaddr_in6*) ent->ifa_netmask);
     } else {
       address->netmask.netmask4 = *((struct sockaddr_in*) ent->ifa_netmask);
diff --git a/Utilities/cmlibuv/src/unix/core.c b/Utilities/cmlibuv/src/unix/core.c
index 7b80ed50f3..e6d61ee2df 100644
--- a/Utilities/cmlibuv/src/unix/core.c
+++ b/Utilities/cmlibuv/src/unix/core.c
@@ -82,10 +82,6 @@ extern char** environ;
 # endif
 #endif
 
-#if defined(__ANDROID_API__) && __ANDROID_API__ < 21
-# include <dlfcn.h>  /* for dlsym */
-#endif
-
 #if defined(__MVS__)
 #include <sys/ioctl.h>
 #endif
@@ -223,15 +219,23 @@ int uv__getiovmax(void) {
 #if defined(IOV_MAX)
   return IOV_MAX;
 #elif defined(_SC_IOV_MAX)
-  static int iovmax = -1;
-  if (iovmax == -1) {
-    iovmax = sysconf(_SC_IOV_MAX);
-    /* On some embedded devices (arm-linux-uclibc based ip camera),
-     * sysconf(_SC_IOV_MAX) can not get the correct value. The return
-     * value is -1 and the errno is EINPROGRESS. Degrade the value to 1.
-     */
-    if (iovmax == -1) iovmax = 1;
-  }
+  static int iovmax_cached = -1;
+  int iovmax;
+
+  iovmax = uv__load_relaxed(&iovmax_cached);
+  if (iovmax != -1)
+    return iovmax;
+
+  /* On some embedded devices (arm-linux-uclibc based ip camera),
+   * sysconf(_SC_IOV_MAX) can not get the correct value. The return
+   * value is -1 and the errno is EINPROGRESS. Degrade the value to 1.
+   */
+  iovmax = sysconf(_SC_IOV_MAX);
+  if (iovmax == -1)
+    iovmax = 1;
+
+  uv__store_relaxed(&iovmax_cached, iovmax);
+
   return iovmax;
 #else
   return 1024;
@@ -382,6 +386,14 @@ int uv_run(uv_loop_t* loop, uv_run_mode mode) {
       timeout = uv_backend_timeout(loop);
 
     uv__io_poll(loop, timeout);
+
+    /* Run one final update on the provider_idle_time in case uv__io_poll
+     * returned because the timeout expired, but no events were received. This
+     * call will be ignored if the provider_entry_time was either never set (if
+     * the timeout == 0) or was already updated b/c an event was received.
+     */
+    uv__metrics_update_idle_time(loop);
+
     uv__run_check(loop);
     uv__run_closing_handles(loop);
 
@@ -665,7 +677,7 @@ ssize_t uv__recvmsg(int fd, struct msghdr* msg, int flags) {
   int* end;
 #if defined(__linux__)
   static int no_msg_cmsg_cloexec;
-  if (no_msg_cmsg_cloexec == 0) {
+  if (0 == uv__load_relaxed(&no_msg_cmsg_cloexec)) {
     rc = recvmsg(fd, msg, flags | 0x40000000);  /* MSG_CMSG_CLOEXEC */
     if (rc != -1)
       return rc;
@@ -674,7 +686,7 @@ ssize_t uv__recvmsg(int fd, struct msghdr* msg, int flags) {
     rc = recvmsg(fd, msg, flags);
     if (rc == -1)
       return UV__ERR(errno);
-    no_msg_cmsg_cloexec = 1;
+    uv__store_relaxed(&no_msg_cmsg_cloexec, 1);
   } else {
     rc = recvmsg(fd, msg, flags);
   }
@@ -1145,13 +1157,6 @@ int uv__getpwuid_r(uv_passwd_t* pwd) {
   size_t shell_size;
   long initsize;
   int r;
-#if defined(__ANDROID_API__) && __ANDROID_API__ < 21
-  int (*getpwuid_r)(uid_t, struct passwd*, char*, size_t, struct passwd**);
-
-  getpwuid_r = dlsym(RTLD_DEFAULT, "getpwuid_r");
-  if (getpwuid_r == NULL)
-    return UV_ENOSYS;
-#endif
 
   if (pwd == NULL)
     return UV_EINVAL;
@@ -1543,3 +1548,78 @@ void uv_sleep(unsigned int msec) {
 
   assert(rc == 0);
 }
+
+int uv__search_path(const char* prog, char* buf, size_t* buflen) {
+  char abspath[UV__PATH_MAX];
+  size_t abspath_size;
+  char trypath[UV__PATH_MAX];
+  char* cloned_path;
+  char* path_env;
+  char* token;
+
+  if (buf == NULL || buflen == NULL || *buflen == 0)
+    return UV_EINVAL;
+
+  /*
+   * Possibilities for prog:
+   * i) an absolute path such as: /home/user/myprojects/nodejs/node
+   * ii) a relative path such as: ./node or ../myprojects/nodejs/node
+   * iii) a bare filename such as "node", after exporting PATH variable
+   *     to its location.
+   */
+
+  /* Case i) and ii) absolute or relative paths */
+  if (strchr(prog, '/') != NULL) {
+    if (realpath(prog, abspath) != abspath)
+      return UV__ERR(errno);
+
+    abspath_size = strlen(abspath);
+
+    *buflen -= 1;
+    if (*buflen > abspath_size)
+      *buflen = abspath_size;
+
+    memcpy(buf, abspath, *buflen);
+    buf[*buflen] = '\0';
+
+    return 0;
+  } 
+
+  /* Case iii). Search PATH environment variable */
+  cloned_path = NULL;
+  token = NULL;
+  path_env = getenv("PATH");
+
+  if (path_env == NULL)
+    return UV_EINVAL;
+
+  cloned_path = uv__strdup(path_env);
+  if (cloned_path == NULL)
+    return UV_ENOMEM;
+
+  token = strtok(cloned_path, ":");
+  while (token != NULL) {
+    snprintf(trypath, sizeof(trypath) - 1, "%s/%s", token, prog);
+    if (realpath(trypath, abspath) == abspath) {
+      /* Check the match is executable */
+      if (access(abspath, X_OK) == 0) {
+        abspath_size = strlen(abspath);
+
+        *buflen -= 1;
+        if (*buflen > abspath_size)
+          *buflen = abspath_size;
+
+        memcpy(buf, abspath, *buflen);
+        buf[*buflen] = '\0';
+
+        uv__free(cloned_path);
+        return 0;
+      }
+    }
+    token = strtok(NULL, ":");
+  }
+  uv__free(cloned_path);
+
+  /* Out of tokens (path entries), and no match found */
+  return UV_EINVAL;
+}
diff --git a/Utilities/cmlibuv/src/unix/darwin-stub.h b/Utilities/cmlibuv/src/unix/darwin-stub.h
index b93cf67c59..433e3efa73 100644
--- a/Utilities/cmlibuv/src/unix/darwin-stub.h
+++ b/Utilities/cmlibuv/src/unix/darwin-stub.h
@@ -27,6 +27,7 @@
 struct CFArrayCallBacks;
 struct CFRunLoopSourceContext;
 struct FSEventStreamContext;
+struct CFRange;
 
 typedef double CFAbsoluteTime;
 typedef double CFTimeInterval;
@@ -42,13 +43,23 @@ typedef unsigned CFStringEncoding;
 typedef void* CFAllocatorRef;
 typedef void* CFArrayRef;
 typedef void* CFBundleRef;
+typedef void* CFDataRef;
 typedef void* CFDictionaryRef;
+typedef void* CFMutableDictionaryRef;
+typedef struct CFRange CFRange;
 typedef void* CFRunLoopRef;
 typedef void* CFRunLoopSourceRef;
 typedef void* CFStringRef;
 typedef void* CFTypeRef;
 typedef void* FSEventStreamRef;
 
+typedef uint32_t IOOptionBits;
+typedef unsigned int io_iterator_t;
+typedef unsigned int io_object_t;
+typedef unsigned int io_service_t;
+typedef unsigned int io_registry_entry_t;
+
+
 typedef void (*FSEventStreamCallback)(const FSEventStreamRef,
                                       void*,
                                       size_t,
@@ -69,6 +80,11 @@ struct FSEventStreamContext {
   void* pad[3];
 };
 
+struct CFRange {
+  CFIndex location;
+  CFIndex length;
+};
+
 static const CFStringEncoding kCFStringEncodingUTF8 = 0x8000100;
 static const OSStatus noErr = 0;
 
diff --git a/Utilities/cmlibuv/src/unix/darwin.c b/Utilities/cmlibuv/src/unix/darwin.c
index 654aba26b1..d0ecd452d8 100644
--- a/Utilities/cmlibuv/src/unix/darwin.c
+++ b/Utilities/cmlibuv/src/unix/darwin.c
@@ -25,6 +25,7 @@
 #include <stdint.h>
 #include <errno.h>
 
+#include <dlfcn.h>
 #include <mach/mach.h>
 #include <mach/mach_time.h>
 #include <mach-o/dyld.h> /* _NSGetExecutablePath */
@@ -32,6 +33,15 @@
 #include <sys/sysctl.h>
 #include <unistd.h>  /* sysconf */
 
+#if !TARGET_OS_IPHONE
+#include "darwin-stub.h"
+#endif
+
+static uv_once_t once = UV_ONCE_INIT;
+static uint64_t (*time_func)(void);
+static mach_timebase_info_data_t timebase;
+
+typedef unsigned char UInt8;
 
 int uv__platform_loop_init(uv_loop_t* loop) {
   loop->cf_state = NULL;
@@ -48,15 +58,19 @@ void uv__platform_loop_delete(uv_loop_t* loop) {
 }
 
 
-uint64_t uv__hrtime(uv_clocktype_t type) {
-  static mach_timebase_info_data_t info;
-
-  if ((ACCESS_ONCE(uint32_t, info.numer) == 0 ||
-       ACCESS_ONCE(uint32_t, info.denom) == 0) &&
-      mach_timebase_info(&info) != KERN_SUCCESS)
+static void uv__hrtime_init_once(void) {
+  if (KERN_SUCCESS != mach_timebase_info(&timebase))
     abort();
 
-  return mach_absolute_time() * info.numer / info.denom;
+  time_func = (uint64_t (*)(void)) dlsym(RTLD_DEFAULT, "mach_continuous_time");
+  if (time_func == NULL)
+    time_func = mach_absolute_time;
+}
+
+
+uint64_t uv__hrtime(uv_clocktype_t type) {
+  uv_once(&once, uv__hrtime_init_once);
+  return time_func() * timebase.numer / timebase.denom;
 }
 
 
@@ -171,17 +185,149 @@ int uv_uptime(double* uptime) {
   return 0;
 }
 
+static int uv__get_cpu_speed(uint64_t* speed) {
+  /* IOKit */
+  void (*pIOObjectRelease)(io_object_t);
+  kern_return_t (*pIOMasterPort)(mach_port_t, mach_port_t*);
+  CFMutableDictionaryRef (*pIOServiceMatching)(const char*);
+  kern_return_t (*pIOServiceGetMatchingServices)(mach_port_t,
+                                                 CFMutableDictionaryRef,
+                                                 io_iterator_t*);
+  io_service_t (*pIOIteratorNext)(io_iterator_t);
+  CFTypeRef (*pIORegistryEntryCreateCFProperty)(io_registry_entry_t,
+                                                CFStringRef,
+                                                CFAllocatorRef,
+                                                IOOptionBits);
+
+  /* CoreFoundation */
+  CFStringRef (*pCFStringCreateWithCString)(CFAllocatorRef,
+                                            const char*,
+                                            CFStringEncoding);
+  CFStringEncoding (*pCFStringGetSystemEncoding)(void);
+  UInt8 *(*pCFDataGetBytePtr)(CFDataRef);
+  CFIndex (*pCFDataGetLength)(CFDataRef);
+  void (*pCFDataGetBytes)(CFDataRef, CFRange, UInt8*);
+  void (*pCFRelease)(CFTypeRef);
+
+  void* core_foundation_handle;
+  void* iokit_handle;
+  int err;
+
+  kern_return_t kr;
+  mach_port_t mach_port;
+  io_iterator_t it;
+  io_object_t service;
+
+  mach_port = 0;
+
+  err = UV_ENOENT;
+  core_foundation_handle = dlopen("/System/Library/Frameworks/"
+                                  "CoreFoundation.framework/"
+                                  "Versions/A/CoreFoundation",
+                                  RTLD_LAZY | RTLD_LOCAL);
+  iokit_handle = dlopen("/System/Library/Frameworks/IOKit.framework/"
+                        "Versions/A/IOKit",
+                        RTLD_LAZY | RTLD_LOCAL);
+
+  if (core_foundation_handle == NULL || iokit_handle == NULL)
+    goto out;
+
+#define V(handle, symbol)                                                     \
+  do {                                                                        \
+    *(void **)(&p ## symbol) = dlsym((handle), #symbol);                      \
+    if (p ## symbol == NULL)                                                  \
+      goto out;                                                               \
+  }                                                                           \
+  while (0)
+  V(iokit_handle, IOMasterPort);
+  V(iokit_handle, IOServiceMatching);
+  V(iokit_handle, IOServiceGetMatchingServices);
+  V(iokit_handle, IOIteratorNext);
+  V(iokit_handle, IOObjectRelease);
+  V(iokit_handle, IORegistryEntryCreateCFProperty);
+  V(core_foundation_handle, CFStringCreateWithCString);
+  V(core_foundation_handle, CFStringGetSystemEncoding);
+  V(core_foundation_handle, CFDataGetBytePtr);
+  V(core_foundation_handle, CFDataGetLength);
+  V(core_foundation_handle, CFDataGetBytes);
+  V(core_foundation_handle, CFRelease);
+#undef V
+
+#define S(s) pCFStringCreateWithCString(NULL, (s), kCFStringEncodingUTF8)
+
+  kr = pIOMasterPort(MACH_PORT_NULL, &mach_port);
+  assert(kr == KERN_SUCCESS);
+  CFMutableDictionaryRef classes_to_match
+      = pIOServiceMatching("IOPlatformDevice");
+  kr = pIOServiceGetMatchingServices(mach_port, classes_to_match, &it);
+  assert(kr == KERN_SUCCESS);
+  service = pIOIteratorNext(it);
+
+  CFStringRef device_type_str = S("device_type");
+  CFStringRef clock_frequency_str = S("clock-frequency");
+
+  while (service != 0) {
+    CFDataRef data;
+    data = pIORegistryEntryCreateCFProperty(service,
+                                            device_type_str,
+                                            NULL,
+                                            0);
+    if (data) {
+      const UInt8* raw = pCFDataGetBytePtr(data);
+      if (strncmp((char*)raw, "cpu", 3) == 0 ||
+          strncmp((char*)raw, "processor", 9) == 0) {
+        CFDataRef freq_ref;
+        freq_ref = pIORegistryEntryCreateCFProperty(service,
+                                                    clock_frequency_str,
+                                                    NULL,
+                                                    0);
+        if (freq_ref) {
+          uint32_t freq;
+          CFIndex len = pCFDataGetLength(freq_ref);
+          CFRange range;
+          range.location = 0;
+          range.length = len;
+
+          pCFDataGetBytes(freq_ref, range, (UInt8*)&freq);
+          *speed = freq;
+          pCFRelease(freq_ref);
+          pCFRelease(data);
+          break;
+        }
+      }
+      pCFRelease(data);
+    }
+
+    service = pIOIteratorNext(it);
+  }
+
+  pIOObjectRelease(it);
+
+  err = 0;
+out:
+  if (core_foundation_handle != NULL)
+    dlclose(core_foundation_handle);
+
+  if (iokit_handle != NULL)
+    dlclose(iokit_handle);
+
+  mach_port_deallocate(mach_task_self(), mach_port);
+
+  return err;
+}
+
 int uv_cpu_info(uv_cpu_info_t** cpu_infos, int* count) {
   unsigned int ticks = (unsigned int)sysconf(_SC_CLK_TCK),
                multiplier = ((uint64_t)1000L / ticks);
   char model[512];
-  uint64_t cpuspeed;
   size_t size;
   unsigned int i;
   natural_t numcpus;
   mach_msg_type_number_t msg_type;
   processor_cpu_load_info_data_t *info;
   uv_cpu_info_t* cpu_info;
+  uint64_t cpuspeed;
+  int err;
 
   size = sizeof(model);
   if (sysctlbyname("machdep.cpu.brand_string", &model, &size, NULL, 0) &&
@@ -189,9 +335,9 @@ int uv_cpu_info(uv_cpu_info_t** cpu_infos, int* count) {
     return UV__ERR(errno);
   }
 
-  size = sizeof(cpuspeed);
-  if (sysctlbyname("hw.cpufrequency", &cpuspeed, &size, NULL, 0))
-    return UV__ERR(errno);
+  err = uv__get_cpu_speed(&cpuspeed);
+  if (err < 0)
+    return err;
 
   if (host_processor_info(mach_host_self(), PROCESSOR_CPU_LOAD_INFO, &numcpus,
                           (processor_info_array_t*)&info,
diff --git a/Utilities/cmlibuv/src/unix/freebsd.c b/Utilities/cmlibuv/src/unix/freebsd.c
index ef77e127c2..fe795a0e75 100644
--- a/Utilities/cmlibuv/src/unix/freebsd.c
+++ b/Utilities/cmlibuv/src/unix/freebsd.c
@@ -56,31 +56,6 @@ int uv__platform_loop_init(uv_loop_t* loop) {
 void uv__platform_loop_delete(uv_loop_t* loop) {
 }
 
-
-#ifdef __DragonFly__
-int uv_exepath(char* buffer, size_t* size) {
-  char abspath[PATH_MAX * 2 + 1];
-  ssize_t abspath_size;
-
-  if (buffer == NULL || size == NULL || *size == 0)
-    return UV_EINVAL;
-
-  abspath_size = readlink("/proc/curproc/file", abspath, sizeof(abspath));
-  if (abspath_size < 0)
-    return UV__ERR(errno);
-
-  assert(abspath_size > 0);
-  *size -= 1;
-
-  if (*size > abspath_size)
-    *size = abspath_size;
-
-  memcpy(buffer, abspath, *size);
-  buffer[*size] = '\0';
-
-  return 0;
-}
-#else
 int uv_exepath(char* buffer, size_t* size) {
   char abspath[PATH_MAX * 2 + 1];
   int mib[4];
@@ -110,7 +85,6 @@ int uv_exepath(char* buffer, size_t* size) {
 
   return 0;
 }
-#endif
 
 uint64_t uv_get_free_memory(void) {
   int freecount;
@@ -290,25 +264,18 @@ int uv_cpu_info(uv_cpu_info_t** cpu_infos, int* count) {
 }
 
 
-int uv__sendmmsg(int fd,
-                 struct uv__mmsghdr* mmsg,
-                 unsigned int vlen,
-                 unsigned int flags) {
+int uv__sendmmsg(int fd, struct uv__mmsghdr* mmsg, unsigned int vlen) {
 #if __FreeBSD__ >= 11
-  return sendmmsg(fd, mmsg, vlen, flags);
+  return sendmmsg(fd, mmsg, vlen, /* flags */ 0);
 #else
   return errno = ENOSYS, -1;
 #endif
 }
 
 
-int uv__recvmmsg(int fd,
-                 struct uv__mmsghdr* mmsg,
-                 unsigned int vlen,
-                 unsigned int flags,
-                 struct timespec* timeout) {
+int uv__recvmmsg(int fd, struct uv__mmsghdr* mmsg, unsigned int vlen) {
 #if __FreeBSD__ >= 11
-  return recvmmsg(fd, mmsg, vlen, flags, timeout);
+  return recvmmsg(fd, mmsg, vlen, 0 /* flags */, NULL /* timeout */);
 #else
   return errno = ENOSYS, -1;
 #endif
diff --git a/Utilities/cmlibuv/src/unix/fs.c b/Utilities/cmlibuv/src/unix/fs.c
index f37749c8f0..6d57cee904 100644
--- a/Utilities/cmlibuv/src/unix/fs.c
+++ b/Utilities/cmlibuv/src/unix/fs.c
@@ -79,7 +79,11 @@
     defined(__NetBSD__)
 # include <sys/param.h>
 # include <sys/mount.h>
-#elif defined(__sun) || defined(__MVS__) || defined(__NetBSD__) || defined(__HAIKU__)
+#elif defined(__sun)      || \
+      defined(__MVS__)    || \
+      defined(__NetBSD__) || \
+      defined(__HAIKU__)  || \
+      defined(__QNX__)
 # include <sys/statvfs.h>
 #else
 # include <sys/statfs.h>
@@ -229,11 +233,7 @@ static ssize_t uv__fs_futime(uv_fs_t* req) {
   struct timespec ts[2];
   ts[0] = uv__fs_to_timespec(req->atime);
   ts[1] = uv__fs_to_timespec(req->mtime);
-#if defined(__ANDROID_API__) && __ANDROID_API__ < 21
-  return utimensat(req->file, NULL, ts, 0);
-#else
   return futimens(req->file, ts);
-#endif
 #elif defined(__APPLE__)                                                      \
     || defined(__DragonFly__)                                                 \
     || defined(__FreeBSD__)                                                   \
@@ -320,13 +320,14 @@ static int uv__fs_mkstemp(uv_fs_t* req) {
   if (path_length < pattern_size ||
       strcmp(path + path_length - pattern_size, pattern)) {
     errno = EINVAL;
-    return -1;
+    r = -1;
+    goto clobber;
   }
 
   uv_once(&once, uv__mkostemp_initonce);
 
 #ifdef O_CLOEXEC
-  if (no_cloexec_support == 0 && uv__mkostemp != NULL) {
+  if (uv__load_relaxed(&no_cloexec_support) == 0 && uv__mkostemp != NULL) {
     r = uv__mkostemp(path, O_CLOEXEC);
 
     if (r >= 0)
@@ -335,11 +336,11 @@ static int uv__fs_mkstemp(uv_fs_t* req) {
     /* If mkostemp() returns EINVAL, it means the kernel doesn't
        support O_CLOEXEC, so we just fallback to mkstemp() below. */
     if (errno != EINVAL)
-      return r;
+      goto clobber;
 
     /* We set the static variable so that next calls don't even
        try to use mkostemp. */
-    no_cloexec_support = 1;
+    uv__store_relaxed(&no_cloexec_support, 1);
   }
 #endif  /* O_CLOEXEC */
 
@@ -361,6 +362,9 @@ static int uv__fs_mkstemp(uv_fs_t* req) {
   if (req->cb != NULL)
     uv_rwlock_rdunlock(&req->loop->cloexec_lock);
 
+clobber:
+  if (r < 0)
+    path[0] = '\0';
   return r;
 }
 
@@ -470,7 +474,7 @@ static ssize_t uv__fs_read(uv_fs_t* req) {
     result = preadv(req->file, (struct iovec*) req->bufs, req->nbufs, req->off);
 #else
 # if defined(__linux__)
-    if (no_preadv) retry:
+    if (uv__load_relaxed(&no_preadv)) retry:
 # endif
     {
       result = uv__fs_preadv(req->file, req->bufs, req->nbufs, req->off);
@@ -482,7 +486,7 @@ static ssize_t uv__fs_read(uv_fs_t* req) {
                           req->nbufs,
                           req->off);
       if (result == -1 && errno == ENOSYS) {
-        no_preadv = 1;
+        uv__store_relaxed(&no_preadv, 1);
         goto retry;
       }
     }
@@ -639,7 +643,11 @@ static int uv__fs_closedir(uv_fs_t* req) {
 
 static int uv__fs_statfs(uv_fs_t* req) {
   uv_statfs_t* stat_fs;
-#if defined(__sun) || defined(__MVS__) || defined(__NetBSD__) || defined(__HAIKU__)
+#if defined(__sun)      || \
+    defined(__MVS__)    || \
+    defined(__NetBSD__) || \
+    defined(__HAIKU__)  || \
+    defined(__QNX__)
   struct statvfs buf;
 
   if (0 != statvfs(req->path, &buf))
@@ -656,7 +664,12 @@ static int uv__fs_statfs(uv_fs_t* req) {
     return -1;
   }
 
-#if defined(__sun) || defined(__MVS__) || defined(__OpenBSD__) || defined(__NetBSD__) || defined(__HAIKU__)
+#if defined(__sun)        || \
+    defined(__MVS__)      || \
+    defined(__OpenBSD__)  || \
+    defined(__NetBSD__)   || \
+    defined(__HAIKU__)    || \
+    defined(__QNX__)
   stat_fs->f_type = 0;  /* f_type is not supported. */
 #else
   stat_fs->f_type = buf.f_type;
@@ -897,8 +910,27 @@ static ssize_t uv__fs_sendfile(uv_fs_t* req) {
     ssize_t r;
 
     off = req->off;
+
+#ifdef __linux__
+    {
+      static int copy_file_range_support = 1;
+
+      if (copy_file_range_support) {
+        r = uv__fs_copy_file_range(in_fd, NULL, out_fd, &off, req->bufsml[0].len, 0);
+
+        if (r == -1 && errno == ENOSYS) {
+          errno = 0;
+          copy_file_range_support = 0;
+        } else {
+          goto ok;
+        }
+      }
+    }
+#endif
+
     r = sendfile(out_fd, in_fd, &off, req->bufsml[0].len);
 
+ok:
     /* sendfile() on SunOS returns EINVAL if the target fd is not a socket but
      * it still writes out data. Fortunately, we can detect it by checking if
      * the offset has been updated.
@@ -1141,7 +1173,7 @@ static ssize_t uv__fs_copyfile(uv_fs_t* req) {
     goto out;
   }
 
-  dst_flags = O_WRONLY | O_CREAT | O_TRUNC;
+  dst_flags = O_WRONLY | O_CREAT;
 
   if (req->flags & UV_FS_COPYFILE_EXCL)
     dst_flags |= O_EXCL;
@@ -1160,16 +1192,26 @@ static ssize_t uv__fs_copyfile(uv_fs_t* req) {
     goto out;
   }
 
-  /* Get the destination file's mode. */
-  if (fstat(dstfd, &dst_statsbuf)) {
-    err = UV__ERR(errno);
-    goto out;
-  }
+  /* If the file is not being opened exclusively, verify that the source and
+     destination are not the same file. If they are the same, bail out early. */
+  if ((req->flags & UV_FS_COPYFILE_EXCL) == 0) {
+    /* Get the destination file's mode. */
+    if (fstat(dstfd, &dst_statsbuf)) {
+      err = UV__ERR(errno);
+      goto out;
+    }
 
-  /* Check if srcfd and dstfd refer to the same file */
-  if (src_statsbuf.st_dev == dst_statsbuf.st_dev &&
-      src_statsbuf.st_ino == dst_statsbuf.st_ino) {
-    goto out;
+    /* Check if srcfd and dstfd refer to the same file */
+    if (src_statsbuf.st_dev == dst_statsbuf.st_dev &&
+        src_statsbuf.st_ino == dst_statsbuf.st_ino) {
+      goto out;
+    }
+
+    /* Truncate the file in case the destination already existed. */
+    if (ftruncate(dstfd, 0) != 0) {
+      err = UV__ERR(errno);
+      goto out;
+    }
   }
 
   if (fchmod(dstfd, src_statsbuf.st_mode) == -1) {
@@ -1365,7 +1407,7 @@ static int uv__fs_statx(int fd,
   int mode;
   int rc;
 
-  if (no_statx)
+  if (uv__load_relaxed(&no_statx))
     return UV_ENOSYS;
 
   dirfd = AT_FDCWD;
@@ -1398,7 +1440,7 @@ static int uv__fs_statx(int fd,
      * implemented, rc might return 1 with 0 set as the error code in which
      * case we return ENOSYS.
      */
-    no_statx = 1;
+    uv__store_relaxed(&no_statx, 1);
     return UV_ENOSYS;
   }
 
@@ -2041,7 +2083,7 @@ void uv_fs_req_cleanup(uv_fs_t* req) {
 
   /* Only necessary for asychronous requests, i.e., requests with a callback.
    * Synchronous ones don't copy their arguments and have req->path and
-   * req->new_path pointing to user-owned memory.  UV_FS_MKDTEMP and 
+   * req->new_path pointing to user-owned memory.  UV_FS_MKDTEMP and
    * UV_FS_MKSTEMP are the exception to the rule, they always allocate memory.
    */
   if (req->path != NULL &&
diff --git a/Utilities/cmlibuv/src/unix/ibmi.c b/Utilities/cmlibuv/src/unix/ibmi.c
index e4c5122bc9..73ab02a7ac 100644
--- a/Utilities/cmlibuv/src/unix/ibmi.c
+++ b/Utilities/cmlibuv/src/unix/ibmi.c
@@ -58,6 +58,9 @@
 #include <as400_protos.h>
 #include <as400_types.h>
 
+char* original_exepath = NULL;
+uv_mutex_t process_title_mutex;
+uv_once_t process_title_mutex_once = UV_ONCE_INIT;
 
 typedef struct {
   int bytes_available;
@@ -171,6 +174,9 @@ static void iconv_a2e(const char* src, unsigned char dst[], size_t length) {
     dst[i] = a2e[' '];
 }
 
+void init_process_title_mutex_once(void) {
+  uv_mutex_init(&process_title_mutex);
+}
 
 static int get_ibmi_system_status(SSTS0200* rcvr) {
   /* rcvrlen is input parameter 2 to QWCRSSTS */
@@ -460,3 +466,36 @@ void uv_free_interface_addresses(uv_interface_address_t* addresses, int count) {
   uv__free(addresses);
 }
 
+char** uv_setup_args(int argc, char** argv) {
+  char exepath[UV__PATH_MAX];
+  char* s;
+  size_t size;
+
+  if (argc > 0) {
+    /* Use argv[0] to determine value for uv_exepath(). */
+    size = sizeof(exepath);
+    if (uv__search_path(argv[0], exepath, &size) == 0) {
+      uv_once(&process_title_mutex_once, init_process_title_mutex_once);
+      uv_mutex_lock(&process_title_mutex);
+      original_exepath = uv__strdup(exepath);
+      uv_mutex_unlock(&process_title_mutex);
+    }
+  }
+
+  return argv;
+}
+
+int uv_set_process_title(const char* title) {
+  return 0;
+}
+
+int uv_get_process_title(char* buffer, size_t size) {
+  if (buffer == NULL || size == 0)
+    return UV_EINVAL;
+
+  buffer[0] = '\0';
+  return 0;
+}
+
+void uv__process_title_cleanup(void) {
+}
diff --git a/Utilities/cmlibuv/src/unix/internal.h b/Utilities/cmlibuv/src/unix/internal.h
index 2549602801..444dc85c59 100644
--- a/Utilities/cmlibuv/src/unix/internal.h
+++ b/Utilities/cmlibuv/src/unix/internal.h
@@ -62,9 +62,7 @@
 # include <AvailabilityMacros.h>
 #endif
 
-#if defined(_POSIX_PATH_MAX)
-# define UV__PATH_MAX _POSIX_PATH_MAX
-#elif defined(PATH_MAX)
+#if defined(PATH_MAX)
 # define UV__PATH_MAX PATH_MAX
 #else
 # define UV__PATH_MAX 8192
@@ -278,6 +276,7 @@ void uv__udp_finish_close(uv_udp_t* handle);
 uv_handle_type uv__handle_type(int fd);
 FILE* uv__open_file(const char* path);
 int uv__getpwuid_r(uv_passwd_t* pwd);
+int uv__search_path(const char* prog, char* buf, size_t* buflen);
 
 /* random */
 int uv__random_devurandom(void* buf, size_t buflen);
@@ -345,15 +344,8 @@ struct uv__mmsghdr {
   unsigned int msg_len;
 };
 
-int uv__recvmmsg(int fd,
-                 struct uv__mmsghdr* mmsg,
-                 unsigned int vlen,
-                 unsigned int flags,
-                 struct timespec* timeout);
-int uv__sendmmsg(int fd,
-                 struct uv__mmsghdr* mmsg,
-                 unsigned int vlen,
-                 unsigned int flags);
+int uv__recvmmsg(int fd, struct uv__mmsghdr* mmsg, unsigned int vlen);
+int uv__sendmmsg(int fd, struct uv__mmsghdr* mmsg, unsigned int vlen);
 #else
 #define HAVE_MMSG 0
 #endif
diff --git a/Utilities/cmlibuv/src/unix/kqueue.c b/Utilities/cmlibuv/src/unix/kqueue.c
index ad09f40313..bf183d5fdc 100644
--- a/Utilities/cmlibuv/src/unix/kqueue.c
+++ b/Utilities/cmlibuv/src/unix/kqueue.c
@@ -82,7 +82,7 @@ int uv__io_fork(uv_loop_t* loop) {
        process. So we sidestep the issue by pretending like we never
        started it in the first place.
     */
-    uv__has_forked_with_cfrunloop = 1;
+    uv__store_relaxed(&uv__has_forked_with_cfrunloop, 1);
     uv__free(loop->cf_state);
     loop->cf_state = NULL;
   }
@@ -129,6 +129,8 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
   int fd;
   int op;
   int i;
+  int user_timeout;
+  int reset_timeout;
 
   if (loop->nfds == 0) {
     assert(QUEUE_EMPTY(&loop->watcher_queue));
@@ -202,7 +204,21 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
   base = loop->time;
   count = 48; /* Benchmarks suggest this gives the best throughput. */
 
+  if (uv__get_internal_fields(loop)->flags & UV_METRICS_IDLE_TIME) {
+    reset_timeout = 1;
+    user_timeout = timeout;
+    timeout = 0;
+  } else {
+    reset_timeout = 0;
+  }
+
   for (;; nevents = 0) {
+    /* Only need to set the provider_entry_time if timeout != 0. The function
+     * will return early if the loop isn't configured with UV_METRICS_IDLE_TIME.
+     */
+    if (timeout != 0)
+      uv__metrics_set_provider_entry_time(loop);
+
     if (timeout != -1) {
       spec.tv_sec = timeout / 1000;
       spec.tv_nsec = (timeout % 1000) * 1000000;
@@ -228,6 +244,15 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
     SAVE_ERRNO(uv__update_time(loop));
 
     if (nfds == 0) {
+      if (reset_timeout != 0) {
+        timeout = user_timeout;
+        reset_timeout = 0;
+        if (timeout == -1)
+          continue;
+        if (timeout > 0)
+          goto update_timeout;
+      }
+
       assert(timeout != -1);
       return;
     }
@@ -236,6 +261,11 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
       if (errno != EINTR)
         abort();
 
+      if (reset_timeout != 0) {
+        timeout = user_timeout;
+        reset_timeout = 0;
+      }
+
       if (timeout == 0)
         return;
 
@@ -276,6 +306,7 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
       if (ev->filter == EVFILT_VNODE) {
         assert(w->events == POLLIN);
         assert(w->pevents == POLLIN);
+        uv__metrics_update_idle_time(loop);
         w->cb(loop, w, ev->fflags); /* XXX always uv__fs_event() */
         nevents++;
         continue;
@@ -337,16 +368,25 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
       /* Run signal watchers last.  This also affects child process watchers
        * because those are implemented in terms of signal watchers.
        */
-      if (w == &loop->signal_io_watcher)
+      if (w == &loop->signal_io_watcher) {
         have_signals = 1;
-      else
+      } else {
+        uv__metrics_update_idle_time(loop);
         w->cb(loop, w, revents);
+      }
 
       nevents++;
     }
 
-    if (have_signals != 0)
+    if (reset_timeout != 0) {
+      timeout = user_timeout;
+      reset_timeout = 0;
+    }
+
+    if (have_signals != 0) {
+      uv__metrics_update_idle_time(loop);
       loop->signal_io_watcher.cb(loop, &loop->signal_io_watcher, POLLIN);
+    }
 
     loop->watchers[loop->nwatchers] = NULL;
     loop->watchers[loop->nwatchers + 1] = NULL;
@@ -487,7 +527,7 @@ int uv_fs_event_start(uv_fs_event_t* handle,
   if (!(statbuf.st_mode & S_IFDIR))
     goto fallback;
 
-  if (!uv__has_forked_with_cfrunloop) {
+  if (0 == uv__load_relaxed(&uv__has_forked_with_cfrunloop)) {
     int r;
     /* The fallback fd is no longer needed */
     uv__close_nocheckstdio(fd);
@@ -522,8 +562,9 @@ int uv_fs_event_stop(uv_fs_event_t* handle) {
   uv__handle_stop(handle);
 
 #if defined(__APPLE__) && MAC_OS_X_VERSION_MAX_ALLOWED >= 1070
-  if (!uv__has_forked_with_cfrunloop && handle->cf_cb != NULL)
-    r = uv__fsevents_close(handle);
+  if (0 == uv__load_relaxed(&uv__has_forked_with_cfrunloop))
+    if (handle->cf_cb != NULL)
+      r = uv__fsevents_close(handle);
 #endif
 
   if (handle->event_watcher.fd != -1) {
diff --git a/Utilities/cmlibuv/src/unix/linux-core.c b/Utilities/cmlibuv/src/unix/linux-core.c
index 99cbb1c8fd..4db2f05053 100644
--- a/Utilities/cmlibuv/src/unix/linux-core.c
+++ b/Utilities/cmlibuv/src/unix/linux-core.c
@@ -85,17 +85,7 @@ static uint64_t read_cpufreq(unsigned int cpunum);
 
 int uv__platform_loop_init(uv_loop_t* loop) {
   int fd;
-
-  /* It was reported that EPOLL_CLOEXEC is not defined on Android API < 21,
-   * a.k.a. Lollipop. Since EPOLL_CLOEXEC is an alias for O_CLOEXEC on all
-   * architectures, we just use that instead.
-   */
-#if defined(__ANDROID_API__) && __ANDROID_API__ < 21
-  fd = -1;
-  errno = ENOSYS;
-#else
   fd = epoll_create1(O_CLOEXEC);
-#endif
 
   /* epoll_create1() can fail either because it's not implemented (old kernel)
    * or because it doesn't understand the O_CLOEXEC flag.
@@ -208,8 +198,10 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
    * that being the largest value I have seen in the wild (and only once.)
    */
   static const int max_safe_timeout = 1789569;
-  static int no_epoll_pwait;
-  static int no_epoll_wait;
+  static int no_epoll_pwait_cached;
+  static int no_epoll_wait_cached;
+  int no_epoll_pwait;
+  int no_epoll_wait;
   struct epoll_event events[1024];
   struct epoll_event* pe;
   struct epoll_event e;
@@ -226,6 +218,8 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
   int fd;
   int op;
   int i;
+  int user_timeout;
+  int reset_timeout;
 
   if (loop->nfds == 0) {
     assert(QUEUE_EMPTY(&loop->watcher_queue));
@@ -281,7 +275,31 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
   count = 48; /* Benchmarks suggest this gives the best throughput. */
   real_timeout = timeout;
 
+  if (uv__get_internal_fields(loop)->flags & UV_METRICS_IDLE_TIME) {
+    reset_timeout = 1;
+    user_timeout = timeout;
+    timeout = 0;
+  } else {
+    reset_timeout = 0;
+    user_timeout = 0;
+  }
+
+  /* You could argue there is a dependency between these two but
+   * ultimately we don't care about their ordering with respect
+   * to one another. Worst case, we make a few system calls that
+   * could have been avoided because another thread already knows
+   * they fail with ENOSYS. Hardly the end of the world.
+   */
+  no_epoll_pwait = uv__load_relaxed(&no_epoll_pwait_cached);
+  no_epoll_wait = uv__load_relaxed(&no_epoll_wait_cached);
+
   for (;;) {
+    /* Only need to set the provider_entry_time if timeout != 0. The function
+     * will return early if the loop isn't configured with UV_METRICS_IDLE_TIME.
+     */
+    if (timeout != 0)
+      uv__metrics_set_provider_entry_time(loop);
+
     /* See the comment for max_safe_timeout for an explanation of why
      * this is necessary.  Executive summary: kernel bug workaround.
      */
@@ -293,25 +311,24 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
         abort();
 
     if (no_epoll_wait != 0 || (sigmask != 0 && no_epoll_pwait == 0)) {
-#if defined(__ANDROID_API__) && __ANDROID_API__ < 21
-      nfds = -1;
-      errno = ENOSYS;
-#else
       nfds = epoll_pwait(loop->backend_fd,
                          events,
                          ARRAY_SIZE(events),
                          timeout,
                          &sigset);
-#endif
-      if (nfds == -1 && errno == ENOSYS)
+      if (nfds == -1 && errno == ENOSYS) {
+        uv__store_relaxed(&no_epoll_pwait_cached, 1);
         no_epoll_pwait = 1;
+      }
     } else {
       nfds = epoll_wait(loop->backend_fd,
                         events,
                         ARRAY_SIZE(events),
                         timeout);
-      if (nfds == -1 && errno == ENOSYS)
+      if (nfds == -1 && errno == ENOSYS) {
+        uv__store_relaxed(&no_epoll_wait_cached, 1);
         no_epoll_wait = 1;
+      }
     }
 
     if (sigmask != 0 && no_epoll_pwait != 0)
@@ -327,6 +344,14 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
     if (nfds == 0) {
       assert(timeout != -1);
 
+      if (reset_timeout != 0) {
+        timeout = user_timeout;
+        reset_timeout = 0;
+      }
+
+      if (timeout == -1)
+        continue;
+
       if (timeout == 0)
         return;
 
@@ -346,6 +371,11 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
       if (errno != EINTR)
         abort();
 
+      if (reset_timeout != 0) {
+        timeout = user_timeout;
+        reset_timeout = 0;
+      }
+
       if (timeout == -1)
         continue;
 
@@ -425,17 +455,26 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
         /* Run signal watchers last.  This also affects child process watchers
          * because those are implemented in terms of signal watchers.
          */
-        if (w == &loop->signal_io_watcher)
+        if (w == &loop->signal_io_watcher) {
           have_signals = 1;
-        else
+        } else {
+          uv__metrics_update_idle_time(loop);
           w->cb(loop, w, pe->events);
+        }
 
         nevents++;
       }
     }
 
-    if (have_signals != 0)
+    if (reset_timeout != 0) {
+      timeout = user_timeout;
+      reset_timeout = 0;
+    }
+
+    if (have_signals != 0) {
+      uv__metrics_update_idle_time(loop);
       loop->signal_io_watcher.cb(loop, &loop->signal_io_watcher, POLLIN);
+    }
 
     loop->watchers[loop->nwatchers] = NULL;
     loop->watchers[loop->nwatchers + 1] = NULL;
@@ -483,18 +522,22 @@ uint64_t uv__hrtime(uv_clocktype_t type) {
   /* TODO(bnoordhuis) Use CLOCK_MONOTONIC_COARSE for UV_CLOCK_PRECISE
    * when it has microsecond granularity or better (unlikely).
    */
-  if (type == UV_CLOCK_FAST && fast_clock_id == -1) {
-    if (clock_getres(CLOCK_MONOTONIC_COARSE, &t) == 0 &&
-        t.tv_nsec <= 1 * 1000 * 1000) {
-      fast_clock_id = CLOCK_MONOTONIC_COARSE;
-    } else {
-      fast_clock_id = CLOCK_MONOTONIC;
-    }
-  }
+  clock_id = CLOCK_MONOTONIC;
+  if (type != UV_CLOCK_FAST)
+    goto done;
+
+  clock_id = uv__load_relaxed(&fast_clock_id);
+  if (clock_id != -1)
+    goto done;
 
   clock_id = CLOCK_MONOTONIC;
-  if (type == UV_CLOCK_FAST)
-    clock_id = fast_clock_id;
+  if (0 == clock_getres(CLOCK_MONOTONIC_COARSE, &t))
+    if (t.tv_nsec <= 1 * 1000 * 1000)
+      clock_id = CLOCK_MONOTONIC_COARSE;
+
+  uv__store_relaxed(&fast_clock_id, clock_id);
+
+done:
 
   if (clock_gettime(clock_id, &t))
     return 0;  /* Not really possible. */
@@ -982,43 +1025,51 @@ void uv__set_process_title(const char* title) {
 }
 
 
-static uint64_t uv__read_proc_meminfo(const char* what) {
-  uint64_t rc;
+static int uv__slurp(const char* filename, char* buf, size_t len) {
   ssize_t n;
-  char* p;
   int fd;
-  char buf[4096];  /* Large enough to hold all of /proc/meminfo. */
 
-  rc = 0;
-  fd = uv__open_cloexec("/proc/meminfo", O_RDONLY);
+  assert(len > 0);
 
+  fd = uv__open_cloexec(filename, O_RDONLY);
   if (fd < 0)
-    return 0;
+    return fd;
 
-  n = read(fd, buf, sizeof(buf) - 1);
+  do
+    n = read(fd, buf, len - 1);
+  while (n == -1 && errno == EINTR);
 
-  if (n <= 0)
-    goto out;
+  if (uv__close_nocheckstdio(fd))
+    abort();
+
+  if (n < 0)
+    return UV__ERR(errno);
 
   buf[n] = '\0';
-  p = strstr(buf, what);
 
-  if (p == NULL)
-    goto out;
+  return 0;
+}
 
-  p += strlen(what);
 
-  if (1 != sscanf(p, "%" PRIu64 " kB", &rc))
-    goto out;
+static uint64_t uv__read_proc_meminfo(const char* what) {
+  uint64_t rc;
+  char* p;
+  char buf[4096];  /* Large enough to hold all of /proc/meminfo. */
+
+  if (uv__slurp("/proc/meminfo", buf, sizeof(buf)))
+    return 0;
 
-  rc *= 1024;
+  p = strstr(buf, what);
 
-out:
+  if (p == NULL)
+    return 0;
 
-  if (uv__close_nocheckstdio(fd))
-    abort();
+  p += strlen(what);
 
-  return rc;
+  rc = 0;
+  sscanf(p, "%" PRIu64 " kB", &rc);
+
+  return rc * 1024;
 }
 
 
@@ -1056,28 +1107,13 @@ uint64_t uv_get_total_memory(void) {
 
 static uint64_t uv__read_cgroups_uint64(const char* cgroup, const char* param) {
   char filename[256];
-  uint64_t rc;
-  int fd;
-  ssize_t n;
   char buf[32];  /* Large enough to hold an encoded uint64_t. */
-
-  snprintf(filename, 256, "/sys/fs/cgroup/%s/%s", cgroup, param);
+  uint64_t rc;
 
   rc = 0;
-  fd = uv__open_cloexec(filename, O_RDONLY);
-
-  if (fd < 0)
-    return 0;
-
-  n = read(fd, buf, sizeof(buf) - 1);
-
-  if (n > 0) {
-    buf[n] = '\0';
+  snprintf(filename, sizeof(filename), "/sys/fs/cgroup/%s/%s", cgroup, param);
+  if (0 == uv__slurp(filename, buf, sizeof(buf)))
     sscanf(buf, "%" PRIu64, &rc);
-  }
-
-  if (uv__close_nocheckstdio(fd))
-    abort();
 
   return rc;
 }
@@ -1091,3 +1127,20 @@ uint64_t uv_get_constrained_memory(void) {
    */
   return uv__read_cgroups_uint64("memory", "memory.limit_in_bytes");
 }
+
+
+void uv_loadavg(double avg[3]) {
+  struct sysinfo info;
+  char buf[128];  /* Large enough to hold all of /proc/loadavg. */
+
+  if (0 == uv__slurp("/proc/loadavg", buf, sizeof(buf)))
+    if (3 == sscanf(buf, "%lf %lf %lf", &avg[0], &avg[1], &avg[2]))
+      return;
+
+  if (sysinfo(&info) < 0)
+    return;
+
+  avg[0] = (double) info.loads[0] / 65536.0;
+  avg[1] = (double) info.loads[1] / 65536.0;
+  avg[2] = (double) info.loads[2] / 65536.0;
+}
diff --git a/Utilities/cmlibuv/src/unix/linux-syscalls.c b/Utilities/cmlibuv/src/unix/linux-syscalls.c
index 742f26ada8..44daaf12d4 100644
--- a/Utilities/cmlibuv/src/unix/linux-syscalls.c
+++ b/Utilities/cmlibuv/src/unix/linux-syscalls.c
@@ -37,8 +37,6 @@
 #ifndef __NR_recvmmsg
 # if defined(__x86_64__)
 #  define __NR_recvmmsg 299
-# elif defined(__i386__)
-#  define __NR_recvmmsg 337
 # elif defined(__arm__)
 #  define __NR_recvmmsg (UV_SYSCALL_BASE + 365)
 # endif
@@ -47,8 +45,6 @@
 #ifndef __NR_sendmmsg
 # if defined(__x86_64__)
 #  define __NR_sendmmsg 307
-# elif defined(__i386__)
-#  define __NR_sendmmsg 345
 # elif defined(__arm__)
 #  define __NR_sendmmsg (UV_SYSCALL_BASE + 374)
 # endif
@@ -94,6 +90,24 @@
 # endif
 #endif /* __NR_pwritev */
 
+#ifndef __NR_copy_file_range
+# if defined(__x86_64__)
+#  define __NR_copy_file_range 326
+# elif defined(__i386__)
+#  define __NR_copy_file_range 377
+# elif defined(__s390__)
+#  define __NR_copy_file_range 375
+# elif defined(__arm__)
+#  define __NR_copy_file_range (UV_SYSCALL_BASE + 391)
+# elif defined(__aarch64__)
+#  define __NR_copy_file_range 285
+# elif defined(__powerpc__)
+#  define __NR_copy_file_range 379
+# elif defined(__arc__)
+#  define __NR_copy_file_range 285
+# endif
+#endif /* __NR_copy_file_range */
+
 #ifndef __NR_statx
 # if defined(__x86_64__)
 #  define __NR_statx 332
@@ -128,25 +142,51 @@
 
 struct uv__mmsghdr;
 
-int uv__sendmmsg(int fd,
-                 struct uv__mmsghdr* mmsg,
-                 unsigned int vlen,
-                 unsigned int flags) {
-#if defined(__NR_sendmmsg)
-  return syscall(__NR_sendmmsg, fd, mmsg, vlen, flags);
+int uv__sendmmsg(int fd, struct uv__mmsghdr* mmsg, unsigned int vlen) {
+#if defined(__i386__)
+  unsigned long args[4];
+  int rc;
+
+  args[0] = (unsigned long) fd;
+  args[1] = (unsigned long) mmsg;
+  args[2] = (unsigned long) vlen;
+  args[3] = /* flags */ 0;
+
+  /* socketcall() raises EINVAL when SYS_SENDMMSG is not supported. */
+  rc = syscall(/* __NR_socketcall */ 102, 20 /* SYS_SENDMMSG */, args);
+  if (rc == -1)
+    if (errno == EINVAL)
+      errno = ENOSYS;
+
+  return rc;
+#elif defined(__NR_sendmmsg)
+  return syscall(__NR_sendmmsg, fd, mmsg, vlen, /* flags */ 0);
 #else
   return errno = ENOSYS, -1;
 #endif
 }
 
 
-int uv__recvmmsg(int fd,
-                 struct uv__mmsghdr* mmsg,
-                 unsigned int vlen,
-                 unsigned int flags,
-                 struct timespec* timeout) {
-#if defined(__NR_recvmmsg)
-  return syscall(__NR_recvmmsg, fd, mmsg, vlen, flags, timeout);
+int uv__recvmmsg(int fd, struct uv__mmsghdr* mmsg, unsigned int vlen) {
+#if defined(__i386__)
+  unsigned long args[5];
+  int rc;
+
+  args[0] = (unsigned long) fd;
+  args[1] = (unsigned long) mmsg;
+  args[2] = (unsigned long) vlen;
+  args[3] = /* flags */ 0;
+  args[4] = /* timeout */ 0;
+
+  /* socketcall() raises EINVAL when SYS_RECVMMSG is not supported. */
+  rc = syscall(/* __NR_socketcall */ 102, 19 /* SYS_RECVMMSG */, args);
+  if (rc == -1)
+    if (errno == EINVAL)
+      errno = ENOSYS;
+
+  return rc;
+#elif defined(__NR_recvmmsg)
+  return syscall(__NR_recvmmsg, fd, mmsg, vlen, /* flags */ 0, /* timeout */ 0);
 #else
   return errno = ENOSYS, -1;
 #endif
@@ -180,6 +220,28 @@ int uv__dup3(int oldfd, int newfd, int flags) {
 }
 
 
+ssize_t
+uv__fs_copy_file_range(int fd_in,
+                       ssize_t* off_in,
+                       int fd_out,
+                       ssize_t* off_out,
+                       size_t len,
+                       unsigned int flags)
+{
+#ifdef __NR_copy_file_range
+  return syscall(__NR_copy_file_range,
+                 fd_in,
+                 off_in,
+                 fd_out,
+                 off_out,
+                 len,
+                 flags);
+#else
+  return errno = ENOSYS, -1;
+#endif
+}
+
+
 int uv__statx(int dirfd,
               const char* path,
               int flags,
diff --git a/Utilities/cmlibuv/src/unix/linux-syscalls.h b/Utilities/cmlibuv/src/unix/linux-syscalls.h
index 2e8fa2a519..761ff32e21 100644
--- a/Utilities/cmlibuv/src/unix/linux-syscalls.h
+++ b/Utilities/cmlibuv/src/unix/linux-syscalls.h
@@ -64,6 +64,13 @@ struct uv__statx {
 ssize_t uv__preadv(int fd, const struct iovec *iov, int iovcnt, int64_t offset);
 ssize_t uv__pwritev(int fd, const struct iovec *iov, int iovcnt, int64_t offset);
 int uv__dup3(int oldfd, int newfd, int flags);
+ssize_t
+uv__fs_copy_file_range(int fd_in,
+                       ssize_t* off_in,
+                       int fd_out,
+                       ssize_t* off_out,
+                       size_t len,
+                       unsigned int flags);
 int uv__statx(int dirfd,
               const char* path,
               int flags,
diff --git a/Utilities/cmlibuv/src/unix/loop.c b/Utilities/cmlibuv/src/unix/loop.c
index c2a03d770f..a88e71c339 100644
--- a/Utilities/cmlibuv/src/unix/loop.c
+++ b/Utilities/cmlibuv/src/unix/loop.c
@@ -28,6 +28,7 @@
 #include <unistd.h>
 
 int uv_loop_init(uv_loop_t* loop) {
+  uv__loop_internal_fields_t* lfields;
   void* saved_data;
   int err;
 
@@ -36,6 +37,15 @@ int uv_loop_init(uv_loop_t* loop) {
   memset(loop, 0, sizeof(*loop));
   loop->data = saved_data;
 
+  lfields = (uv__loop_internal_fields_t*) uv__calloc(1, sizeof(*lfields));
+  if (lfields == NULL)
+    return UV_ENOMEM;
+  loop->internal_fields = lfields;
+
+  err = uv_mutex_init(&lfields->loop_metrics.lock);
+  if (err)
+    goto fail_metrics_mutex_init;
+
   heap_init((struct heap*) &loop->timer_heap);
   QUEUE_INIT(&loop->wq);
   QUEUE_INIT(&loop->idle_handles);
@@ -66,7 +76,7 @@ int uv_loop_init(uv_loop_t* loop) {
 
   err = uv__platform_loop_init(loop);
   if (err)
-    return err;
+    goto fail_platform_init;
 
   uv__signal_global_once_init();
   err = uv_signal_init(loop, &loop->child_watcher);
@@ -106,6 +116,15 @@ fail_rwlock_init:
 fail_signal_init:
   uv__platform_loop_delete(loop);
 
+fail_platform_init:
+  uv_mutex_destroy(&lfields->loop_metrics.lock);
+
+fail_metrics_mutex_init:
+  uv__free(lfields);
+  loop->internal_fields = NULL;
+
+  uv__free(loop->watchers);
+  loop->nwatchers = 0;
   return err;
 }
 
@@ -144,6 +163,8 @@ int uv_loop_fork(uv_loop_t* loop) {
 
 
 void uv__loop_close(uv_loop_t* loop) {
+  uv__loop_internal_fields_t* lfields;
+
   uv__signal_loop_cleanup(loop);
   uv__platform_loop_delete(loop);
   uv__async_stop(loop);
@@ -179,10 +200,23 @@ void uv__loop_close(uv_loop_t* loop) {
   uv__free(loop->watchers);
   loop->watchers = NULL;
   loop->nwatchers = 0;
+
+  lfields = uv__get_internal_fields(loop);
+  uv_mutex_destroy(&lfields->loop_metrics.lock);
+  uv__free(lfields);
+  loop->internal_fields = NULL;
 }
 
 
 int uv__loop_configure(uv_loop_t* loop, uv_loop_option option, va_list ap) {
+  uv__loop_internal_fields_t* lfields;
+
+  lfields = uv__get_internal_fields(loop);
+  if (option == UV_METRICS_IDLE_TIME) {
+    lfields->flags |= UV_METRICS_IDLE_TIME;
+    return 0;
+  }
+
   if (option != UV_LOOP_BLOCK_SIGNAL)
     return UV_ENOSYS;
 
diff --git a/Utilities/cmlibuv/src/unix/os390-syscalls.c b/Utilities/cmlibuv/src/unix/os390-syscalls.c
index 424cc486a8..491e950c50 100644
--- a/Utilities/cmlibuv/src/unix/os390-syscalls.c
+++ b/Utilities/cmlibuv/src/unix/os390-syscalls.c
@@ -33,7 +33,6 @@
 #pragma linkage(BPX4CTW, OS)
 #pragma linkage(BPX1CTW, OS)
 
-static int number_of_epolls;
 static QUEUE global_epoll_queue;
 static uv_mutex_t global_epoll_lock;
 static uv_once_t once = UV_ONCE_INIT;
diff --git a/Utilities/cmlibuv/src/unix/os390.c b/Utilities/cmlibuv/src/unix/os390.c
index dce169b9fb..3bb44266d9 100644
--- a/Utilities/cmlibuv/src/unix/os390.c
+++ b/Utilities/cmlibuv/src/unix/os390.c
@@ -254,8 +254,6 @@ static int getexe(const int pid, char* buf, size_t len) {
 int uv_exepath(char* buffer, size_t* size) {
   int res;
   char args[PATH_MAX];
-  char abspath[PATH_MAX];
-  size_t abspath_size;
   int pid;
 
   if (buffer == NULL || size == NULL || *size == 0)
@@ -266,69 +264,7 @@ int uv_exepath(char* buffer, size_t* size) {
   if (res < 0)
     return UV_EINVAL;
 
-  /*
-   * Possibilities for args:
-   * i) an absolute path such as: /home/user/myprojects/nodejs/node
-   * ii) a relative path such as: ./node or ../myprojects/nodejs/node
-   * iii) a bare filename such as "node", after exporting PATH variable
-   *     to its location.
-   */
-
-  /* Case i) and ii) absolute or relative paths */
-  if (strchr(args, '/') != NULL) {
-    if (realpath(args, abspath) != abspath)
-      return UV__ERR(errno);
-
-    abspath_size = strlen(abspath);
-
-    *size -= 1;
-    if (*size > abspath_size)
-      *size = abspath_size;
-
-    memcpy(buffer, abspath, *size);
-    buffer[*size] = '\0';
-
-    return 0;
-  } else {
-    /* Case iii). Search PATH environment variable */
-    char trypath[PATH_MAX];
-    char* clonedpath = NULL;
-    char* token = NULL;
-    char* path = getenv("PATH");
-
-    if (path == NULL)
-      return UV_EINVAL;
-
-    clonedpath = uv__strdup(path);
-    if (clonedpath == NULL)
-      return UV_ENOMEM;
-
-    token = strtok(clonedpath, ":");
-    while (token != NULL) {
-      snprintf(trypath, sizeof(trypath) - 1, "%s/%s", token, args);
-      if (realpath(trypath, abspath) == abspath) {
-        /* Check the match is executable */
-        if (access(abspath, X_OK) == 0) {
-          abspath_size = strlen(abspath);
-
-          *size -= 1;
-          if (*size > abspath_size)
-            *size = abspath_size;
-
-          memcpy(buffer, abspath, *size);
-          buffer[*size] = '\0';
-
-          uv__free(clonedpath);
-          return 0;
-        }
-      }
-      token = strtok(NULL, ":");
-    }
-    uv__free(clonedpath);
-
-    /* Out of tokens (path entries), and no match found */
-    return UV_EINVAL;
-  }
+  return uv__search_path(args, buffer, size);
 }
 
 
@@ -818,6 +754,8 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
   int fd;
   int op;
   int i;
+  int user_timeout;
+  int reset_timeout;
 
   if (loop->nfds == 0) {
     assert(QUEUE_EMPTY(&loop->watcher_queue));
@@ -870,8 +808,22 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
   real_timeout = timeout;
   int nevents = 0;
 
+  if (uv__get_internal_fields(loop)->flags & UV_METRICS_IDLE_TIME) {
+    reset_timeout = 1;
+    user_timeout = timeout;
+    timeout = 0;
+  } else {
+    reset_timeout = 0;
+  }
+
   nfds = 0;
   for (;;) {
+    /* Only need to set the provider_entry_time if timeout != 0. The function
+     * will return early if the loop isn't configured with UV_METRICS_IDLE_TIME.
+     */
+    if (timeout != 0)
+      uv__metrics_set_provider_entry_time(loop);
+
     if (sizeof(int32_t) == sizeof(long) && timeout >= max_safe_timeout)
       timeout = max_safe_timeout;
 
@@ -887,12 +839,21 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
     if (nfds == 0) {
       assert(timeout != -1);
 
-      if (timeout > 0) {
-        timeout = real_timeout - timeout;
-        continue;
+      if (reset_timeout != 0) {
+        timeout = user_timeout;
+        reset_timeout = 0;
       }
 
-      return;
+      if (timeout == -1)
+        continue;
+
+      if (timeout == 0)
+        return;
+
+      /* We may have been inside the system call for longer than |timeout|
+       * milliseconds so we need to update the timestamp to avoid drift.
+       */
+      goto update_timeout;
     }
 
     if (nfds == -1) {
@@ -900,6 +861,11 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
       if (errno != EINTR)
         abort();
 
+      if (reset_timeout != 0) {
+        timeout = user_timeout;
+        reset_timeout = 0;
+      }
+
       if (timeout == -1)
         continue;
 
@@ -954,6 +920,7 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
         pe->events |= w->pevents & (POLLIN | POLLOUT);
 
       if (pe->events != 0) {
+        uv__metrics_update_idle_time(loop);
         w->cb(loop, w, pe->events);
         nevents++;
       }
@@ -961,6 +928,11 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
     loop->watchers[loop->nwatchers] = NULL;
     loop->watchers[loop->nwatchers + 1] = NULL;
 
+    if (reset_timeout != 0) {
+      timeout = user_timeout;
+      reset_timeout = 0;
+    }
+
     if (nevents != 0) {
       if (nfds == ARRAY_SIZE(events) && --count != 0) {
         /* Poll for more events but don't block this time. */
diff --git a/Utilities/cmlibuv/src/unix/posix-poll.c b/Utilities/cmlibuv/src/unix/posix-poll.c
index 766e83205d..0f4bf93874 100644
--- a/Utilities/cmlibuv/src/unix/posix-poll.c
+++ b/Utilities/cmlibuv/src/unix/posix-poll.c
@@ -144,6 +144,8 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
   int have_signals;
   struct pollfd* pe;
   int fd;
+  int user_timeout;
+  int reset_timeout;
 
   if (loop->nfds == 0) {
     assert(QUEUE_EMPTY(&loop->watcher_queue));
@@ -177,11 +179,25 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
   assert(timeout >= -1);
   time_base = loop->time;
 
+  if (uv__get_internal_fields(loop)->flags & UV_METRICS_IDLE_TIME) {
+    reset_timeout = 1;
+    user_timeout = timeout;
+    timeout = 0;
+  } else {
+    reset_timeout = 0;
+  }
+
   /* Loop calls to poll() and processing of results.  If we get some
    * results from poll() but they turn out not to be interesting to
    * our caller then we need to loop around and poll() again.
    */
   for (;;) {
+    /* Only need to set the provider_entry_time if timeout != 0. The function
+     * will return early if the loop isn't configured with UV_METRICS_IDLE_TIME.
+     */
+    if (timeout != 0)
+      uv__metrics_set_provider_entry_time(loop);
+
     if (pset != NULL)
       if (pthread_sigmask(SIG_BLOCK, pset, NULL))
         abort();
@@ -197,6 +213,15 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
     SAVE_ERRNO(uv__update_time(loop));
 
     if (nfds == 0) {
+      if (reset_timeout != 0) {
+        timeout = user_timeout;
+        reset_timeout = 0;
+        if (timeout == -1)
+          continue;
+        if (timeout > 0)
+          goto update_timeout;
+      }
+
       assert(timeout != -1);
       return;
     }
@@ -205,6 +230,11 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
       if (errno != EINTR)
         abort();
 
+      if (reset_timeout != 0) {
+        timeout = user_timeout;
+        reset_timeout = 0;
+      }
+
       if (timeout == -1)
         continue;
 
@@ -254,6 +284,7 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
         if (w == &loop->signal_io_watcher) {
           have_signals = 1;
         } else {
+          uv__metrics_update_idle_time(loop);
           w->cb(loop, w, pe->revents);
         }
 
@@ -261,8 +292,15 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
       }
     }
 
-    if (have_signals != 0)
+    if (reset_timeout != 0) {
+      timeout = user_timeout;
+      reset_timeout = 0;
+    }
+
+    if (have_signals != 0) {
+      uv__metrics_update_idle_time(loop);
       loop->signal_io_watcher.cb(loop, &loop->signal_io_watcher, POLLIN);
+    }
 
     loop->poll_fds_iterating = 0;
 
diff --git a/Utilities/cmlibuv/src/unix/proctitle.c b/Utilities/cmlibuv/src/unix/proctitle.c
index 4ee991fcc3..9ffe5b629c 100644
--- a/Utilities/cmlibuv/src/unix/proctitle.c
+++ b/Utilities/cmlibuv/src/unix/proctitle.c
@@ -100,6 +100,10 @@ int uv_set_process_title(const char* title) {
   struct uv__process_title* pt;
   size_t len;
 
+  /* If uv_setup_args wasn't called or failed, we can't continue. */
+  if (args_mem == NULL)
+    return UV_ENOBUFS;
+
   pt = &process_title;
   len = strlen(title);
 
@@ -126,6 +130,10 @@ int uv_get_process_title(char* buffer, size_t size) {
   if (buffer == NULL || size == 0)
     return UV_EINVAL;
 
+  /* If uv_setup_args wasn't called or failed, we can't continue. */
+  if (args_mem == NULL)
+    return UV_ENOBUFS;
+
   uv_once(&process_title_mutex_once, init_process_title_mutex_once);
   uv_mutex_lock(&process_title_mutex);
 
diff --git a/Utilities/cmlibuv/src/unix/pthread-fixes.c b/Utilities/cmlibuv/src/unix/pthread-fixes.c
index fb17995846..022d79c4e2 100644
--- a/Utilities/cmlibuv/src/unix/pthread-fixes.c
+++ b/Utilities/cmlibuv/src/unix/pthread-fixes.c
@@ -30,6 +30,8 @@
 */
 
 /* Android versions < 4.1 have a broken pthread_sigmask. */
+#include "uv-common.h"
+
 #include <errno.h>
 #include <pthread.h>
 #include <signal.h>
@@ -38,13 +40,13 @@ int uv__pthread_sigmask(int how, const sigset_t* set, sigset_t* oset) {
   static int workaround;
   int err;
 
-  if (workaround) {
+  if (uv__load_relaxed(&workaround)) {
     return sigprocmask(how, set, oset);
   } else {
     err = pthread_sigmask(how, set, oset);
     if (err) {
       if (err == EINVAL && sigprocmask(how, set, oset) == 0) {
-        workaround = 1;
+        uv__store_relaxed(&workaround, 1);
         return 0;
       } else {
         return -1;
diff --git a/Utilities/cmlibuv/src/unix/qnx.c b/Utilities/cmlibuv/src/unix/qnx.c
new file mode 100644
index 0000000000..ca148d349f
--- /dev/null
+++ b/Utilities/cmlibuv/src/unix/qnx.c
@@ -0,0 +1,137 @@
+/* Copyright libuv contributors. All rights reserved.
+  *
+  * Permission is hereby granted, free of charge, to any person obtaining a copy
+  * of this software and associated documentation files (the "Software"), to
+  * deal in the Software without restriction, including without limitation the
+  * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+  * sell copies of the Software, and to permit persons to whom the Software is
+  * furnished to do so, subject to the following conditions:
+  *
+  * The above copyright notice and this permission notice shall be included in
+  * all copies or substantial portions of the Software.
+  *
+  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+  * IN THE SOFTWARE.
+  */
+
+#include "uv.h"
+#include "internal.h"
+
+#include <string.h>
+#include <sys/process.h>
+#include <sys/neutrino.h>
+#include <sys/memmsg.h>
+#include <sys/syspage.h>
+#include <sys/procfs.h>
+
+static void
+get_mem_info(uint64_t* totalmem, uint64_t* freemem) {
+  mem_info_t msg;
+
+  memset(&msg, 0, sizeof(msg));
+  msg.i.type = _MEM_INFO;
+  msg.i.fd = -1;
+
+  if (MsgSend(MEMMGR_COID, &msg.i, sizeof(msg.i), &msg.o, sizeof(msg.o))
+      != -1) {
+    *totalmem = msg.o.info.__posix_tmi_total;
+    *freemem = msg.o.info.posix_tmi_length;
+  } else {
+    *totalmem = 0;
+    *freemem = 0;
+  }
+}
+
+
+void uv_loadavg(double avg[3]) {
+  avg[0] = 0.0;
+  avg[1] = 0.0;
+  avg[2] = 0.0;
+}
+
+
+int uv_exepath(char* buffer, size_t* size) {
+  char path[PATH_MAX];
+  if (buffer == NULL || size == NULL || *size == 0)
+    return UV_EINVAL;
+
+  realpath(_cmdname(NULL), path);
+  strlcpy(buffer, path, *size);
+  *size = strlen(buffer);
+  return 0;
+}
+
+
+uint64_t uv_get_free_memory(void) {
+  uint64_t totalmem;
+  uint64_t freemem;
+  get_mem_info(&totalmem, &freemem);
+  return freemem;
+}
+
+
+uint64_t uv_get_total_memory(void) {
+  uint64_t totalmem;
+  uint64_t freemem;
+  get_mem_info(&totalmem, &freemem);
+  return totalmem;
+}
+
+
+uint64_t uv_get_constrained_memory(void) {
+  return 0;
+}
+
+
+int uv_resident_set_memory(size_t* rss) {
+  int fd;
+  procfs_asinfo asinfo;
+
+  fd = uv__open_cloexec("/proc/self/ctl", O_RDONLY);
+  if (fd == -1)
+    return UV__ERR(errno);
+
+  if (devctl(fd, DCMD_PROC_ASINFO, &asinfo, sizeof(asinfo), 0) == -1) {
+    uv__close(fd);
+    return UV__ERR(errno);
+  }
+
+  uv__close(fd);
+  *rss = asinfo.rss;
+  return 0;
+}
+
+
+int uv_uptime(double* uptime) {
+  struct qtime_entry* qtime = _SYSPAGE_ENTRY(_syspage_ptr, qtime);
+  *uptime = (qtime->nsec / 1000000000.0);
+  return 0;
+}
+
+
+int uv_cpu_info(uv_cpu_info_t** cpu_infos, int* count) {
+  struct cpuinfo_entry* cpuinfo =
+    (struct cpuinfo_entry*)_SYSPAGE_ENTRY(_syspage_ptr, new_cpuinfo);
+  size_t cpuinfo_size = _SYSPAGE_ELEMENT_SIZE(_syspage_ptr, cpuinfo);
+  struct strings_entry* strings = _SYSPAGE_ENTRY(_syspage_ptr, strings);
+  int num_cpus = _syspage_ptr->num_cpu;
+  int i;
+
+  *count = num_cpus;
+  *cpu_infos = uv__malloc(num_cpus * sizeof(**cpu_infos));
+  if (*cpu_infos == NULL)
+    return UV_ENOMEM;
+
+  for (i = 0; i < num_cpus; i++) {
+    (*cpu_infos)[i].model = strdup(&strings->data[cpuinfo->name]);
+    (*cpu_infos)[i].speed = cpuinfo->speed;
+    SYSPAGE_ARRAY_ADJ_OFFSET(cpuinfo, cpuinfo, cpuinfo_size);
+  }
+
+  return 0;
+}
diff --git a/Utilities/cmlibuv/src/unix/signal.c b/Utilities/cmlibuv/src/unix/signal.c
index 1c83e095bc..f40a3e54eb 100644
--- a/Utilities/cmlibuv/src/unix/signal.c
+++ b/Utilities/cmlibuv/src/unix/signal.c
@@ -143,6 +143,8 @@ static void uv__signal_block_and_lock(sigset_t* saved_sigmask) {
   if (sigfillset(&new_mask))
     abort();
 
+  /* to shut up valgrind */
+  sigemptyset(saved_sigmask);
   if (pthread_sigmask(SIG_SETMASK, &new_mask, saved_sigmask))
     abort();
 
diff --git a/Utilities/cmlibuv/src/unix/sunos.c b/Utilities/cmlibuv/src/unix/sunos.c
index 9697648054..2166e8f08e 100644
--- a/Utilities/cmlibuv/src/unix/sunos.c
+++ b/Utilities/cmlibuv/src/unix/sunos.c
@@ -158,6 +158,7 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
   sigset_t set;
   uint64_t base;
   uint64_t diff;
+  uint64_t idle_poll;
   unsigned int nfds;
   unsigned int i;
   int saved_errno;
@@ -166,6 +167,8 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
   int count;
   int err;
   int fd;
+  int user_timeout;
+  int reset_timeout;
 
   if (loop->nfds == 0) {
     assert(QUEUE_EMPTY(&loop->watcher_queue));
@@ -203,7 +206,21 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
   base = loop->time;
   count = 48; /* Benchmarks suggest this gives the best throughput. */
 
+  if (uv__get_internal_fields(loop)->flags & UV_METRICS_IDLE_TIME) {
+    reset_timeout = 1;
+    user_timeout = timeout;
+    timeout = 0;
+  } else {
+    reset_timeout = 0;
+  }
+
   for (;;) {
+    /* Only need to set the provider_entry_time if timeout != 0. The function
+     * will return early if the loop isn't configured with UV_METRICS_IDLE_TIME.
+     */
+    if (timeout != 0)
+      uv__metrics_set_provider_entry_time(loop);
+
     if (timeout != -1) {
       spec.tv_sec = timeout / 1000;
       spec.tv_nsec = (timeout % 1000) * 1000000;
@@ -246,6 +263,11 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
     SAVE_ERRNO(uv__update_time(loop));
 
     if (events[0].portev_source == 0) {
+      if (reset_timeout != 0) {
+        timeout = user_timeout;
+        reset_timeout = 0;
+      }
+
       if (timeout == 0)
         return;
 
@@ -286,10 +308,12 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
       /* Run signal watchers last.  This also affects child process watchers
        * because those are implemented in terms of signal watchers.
        */
-      if (w == &loop->signal_io_watcher)
+      if (w == &loop->signal_io_watcher) {
         have_signals = 1;
-      else
+      } else {
+        uv__metrics_update_idle_time(loop);
         w->cb(loop, w, pe->portev_events);
+      }
 
       nevents++;
 
@@ -301,8 +325,15 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
         QUEUE_INSERT_TAIL(&loop->watcher_queue, &w->watcher_queue);
     }
 
-    if (have_signals != 0)
+    if (reset_timeout != 0) {
+      timeout = user_timeout;
+      reset_timeout = 0;
+    }
+
+    if (have_signals != 0) {
+      uv__metrics_update_idle_time(loop);
       loop->signal_io_watcher.cb(loop, &loop->signal_io_watcher, POLLIN);
+    }
 
     loop->watchers[loop->nwatchers] = NULL;
     loop->watchers[loop->nwatchers + 1] = NULL;
diff --git a/Utilities/cmlibuv/src/unix/tcp.c b/Utilities/cmlibuv/src/unix/tcp.c
index d47e9433db..18acd20df1 100644
--- a/Utilities/cmlibuv/src/unix/tcp.c
+++ b/Utilities/cmlibuv/src/unix/tcp.c
@@ -326,16 +326,19 @@ int uv_tcp_close_reset(uv_tcp_t* handle, uv_close_cb close_cb) {
 
 
 int uv_tcp_listen(uv_tcp_t* tcp, int backlog, uv_connection_cb cb) {
-  static int single_accept = -1;
+  static int single_accept_cached = -1;
   unsigned long flags;
+  int single_accept;
   int err;
 
   if (tcp->delayed_error)
     return tcp->delayed_error;
 
+  single_accept = uv__load_relaxed(&single_accept_cached);
   if (single_accept == -1) {
     const char* val = getenv("UV_TCP_SINGLE_ACCEPT");
     single_accept = (val != NULL && atoi(val) != 0);  /* Off by default. */
+    uv__store_relaxed(&single_accept_cached, single_accept);
   }
 
   if (single_accept)
diff --git a/Utilities/cmlibuv/src/unix/thread.c b/Utilities/cmlibuv/src/unix/thread.c
index f93aa532ff..8aeb0ca382 100644
--- a/Utilities/cmlibuv/src/unix/thread.c
+++ b/Utilities/cmlibuv/src/unix/thread.c
@@ -172,10 +172,11 @@ static size_t thread_stack_size(void) {
 #if defined(__APPLE__) || defined(__linux__)
   struct rlimit lim;
 
-  if (getrlimit(RLIMIT_STACK, &lim))
-    abort();
-
-  if (lim.rlim_cur != RLIM_INFINITY) {
+  /* getrlimit() can fail on some aarch64 systems due to a glibc bug where
+   * the system call wrapper invokes the wrong system call. Don't treat
+   * that as fatal, just use the default stack size instead.
+   */
+  if (0 == getrlimit(RLIMIT_STACK, &lim) && lim.rlim_cur != RLIM_INFINITY) {
     /* pthread_attr_setstacksize() expects page-aligned values. */
     lim.rlim_cur -= lim.rlim_cur % (rlim_t) getpagesize();
 
@@ -708,7 +709,7 @@ int uv_cond_init(uv_cond_t* cond) {
   if (err)
     return UV__ERR(err);
 
-#if !(defined(__ANDROID_API__) && __ANDROID_API__ < 21) && !defined(__hpux)
+#if !defined(__hpux)
   err = pthread_condattr_setclock(&attr, CLOCK_MONOTONIC);
   if (err)
     goto error2;
@@ -804,16 +805,7 @@ int uv_cond_timedwait(uv_cond_t* cond, uv_mutex_t* mutex, uint64_t timeout) {
 #endif
   ts.tv_sec = timeout / NANOSEC;
   ts.tv_nsec = timeout % NANOSEC;
-#if defined(__ANDROID_API__) && __ANDROID_API__ < 21
-
-  /*
-   * The bionic pthread implementation doesn't support CLOCK_MONOTONIC,
-   * but has this alternative function instead.
-   */
-  r = pthread_cond_timedwait_monotonic_np(cond, mutex, &ts);
-#else
   r = pthread_cond_timedwait(cond, mutex, &ts);
-#endif /* __ANDROID_API__ */
 #endif
 
 
diff --git a/Utilities/cmlibuv/src/unix/udp.c b/Utilities/cmlibuv/src/unix/udp.c
index 21b922fda1..7d699a1675 100644
--- a/Utilities/cmlibuv/src/unix/udp.c
+++ b/Utilities/cmlibuv/src/unix/udp.c
@@ -42,6 +42,11 @@
 # define IPV6_DROP_MEMBERSHIP IPV6_LEAVE_GROUP
 #endif
 
+union uv__sockaddr {
+  struct sockaddr_in6 in6;
+  struct sockaddr_in in;
+  struct sockaddr addr;
+};
 
 static void uv__udp_run_completed(uv_udp_t* handle);
 static void uv__udp_io(uv_loop_t* loop, uv__io_t* w, unsigned int revents);
@@ -68,12 +73,12 @@ static void uv__udp_mmsg_init(void) {
   s = uv__socket(AF_INET, SOCK_DGRAM, 0);
   if (s < 0)
     return;
-  ret = uv__sendmmsg(s, NULL, 0, 0);
+  ret = uv__sendmmsg(s, NULL, 0);
   if (ret == 0 || errno != ENOSYS) {
     uv__sendmmsg_avail = 1;
     uv__recvmmsg_avail = 1;
   } else {
-    ret = uv__recvmmsg(s, NULL, 0, 0, NULL);
+    ret = uv__recvmmsg(s, NULL, 0);
     if (ret == 0 || errno != ENOSYS)
       uv__recvmmsg_avail = 1;
   }
@@ -208,7 +213,7 @@ static int uv__udp_recvmmsg(uv_udp_t* handle, uv_buf_t* buf) {
   }
 
   do
-    nread = uv__recvmmsg(handle->io_watcher.fd, msgs, chunks, 0, NULL);
+    nread = uv__recvmmsg(handle->io_watcher.fd, msgs, chunks);
   while (nread == -1 && errno == EINTR);
 
   if (nread < 1) {
@@ -233,7 +238,7 @@ static int uv__udp_recvmmsg(uv_udp_t* handle, uv_buf_t* buf) {
 
     /* one last callback so the original buffer is freed */
     if (handle->recv_cb != NULL)
-      handle->recv_cb(handle, 0, buf, NULL, 0);
+      handle->recv_cb(handle, 0, buf, NULL, UV_UDP_MMSG_FREE);
   }
   return nread;
 }
@@ -265,14 +270,11 @@ static void uv__udp_recvmsg(uv_udp_t* handle) {
     assert(buf.base != NULL);
 
 #if HAVE_MMSG
-    if (handle->flags & UV_HANDLE_UDP_RECVMMSG) {
-      uv_once(&once, uv__udp_mmsg_init);
-      if (uv__recvmmsg_avail) {
-        nread = uv__udp_recvmmsg(handle, &buf);
-        if (nread > 0)
-          count -= nread;
-        continue;
-      }
+    if (uv_udp_using_recvmmsg(handle)) {
+      nread = uv__udp_recvmmsg(handle, &buf);
+      if (nread > 0)
+        count -= nread;
+      continue;
     }
 #endif
 
@@ -354,7 +356,7 @@ write_queue_drain:
   }
 
   do
-    npkts = uv__sendmmsg(handle->io_watcher.fd, h, pkts, 0);
+    npkts = uv__sendmmsg(handle->io_watcher.fd, h, pkts);
   while (npkts == -1 && errno == EINTR);
 
   if (npkts < 1) {
@@ -362,7 +364,7 @@ write_queue_drain:
       return;
     for (i = 0, q = QUEUE_HEAD(&handle->write_queue);
          i < pkts && q != &handle->write_queue;
-         ++i, q = QUEUE_HEAD(q)) {
+         ++i, q = QUEUE_HEAD(&handle->write_queue)) {
       assert(q != NULL);
       req = QUEUE_DATA(q, uv_udp_send_t, queue);
       assert(req != NULL);
@@ -567,11 +569,7 @@ int uv__udp_bind(uv_udp_t* handle,
 static int uv__udp_maybe_deferred_bind(uv_udp_t* handle,
                                        int domain,
                                        unsigned int flags) {
-  union {
-    struct sockaddr_in6 in6;
-    struct sockaddr_in in;
-    struct sockaddr addr;
-  } taddr;
+  union uv__sockaddr taddr;
   socklen_t addrlen;
 
   if (handle->io_watcher.fd != -1)
@@ -853,7 +851,11 @@ static int uv__udp_set_membership6(uv_udp_t* handle,
 }
 
 
-#if !defined(__OpenBSD__) && !defined(__NetBSD__) && !defined(__ANDROID__)
+#if !defined(__OpenBSD__) &&                                        \
+    !defined(__NetBSD__) &&                                         \
+    !defined(__ANDROID__) &&                                        \
+    !defined(__DragonFly__) &                                       \
+    !defined(__QNX__)
 static int uv__udp_set_source_membership4(uv_udp_t* handle,
                                           const struct sockaddr_in* multicast_addr,
                                           const char* interface_addr,
@@ -924,8 +926,10 @@ static int uv__udp_set_source_membership6(uv_udp_t* handle,
     mreq.gsr_interface = 0;
   }
 
-  memcpy(&mreq.gsr_group, multicast_addr, sizeof(mreq.gsr_group));
-  memcpy(&mreq.gsr_source, source_addr, sizeof(mreq.gsr_source));
+  STATIC_ASSERT(sizeof(mreq.gsr_group) >= sizeof(*multicast_addr));
+  STATIC_ASSERT(sizeof(mreq.gsr_source) >= sizeof(*source_addr));
+  memcpy(&mreq.gsr_group, multicast_addr, sizeof(*multicast_addr));
+  memcpy(&mreq.gsr_source, source_addr, sizeof(*source_addr));
 
   if (membership == UV_JOIN_GROUP)
     optname = MCAST_JOIN_SOURCE_GROUP;
@@ -973,6 +977,17 @@ int uv__udp_init_ex(uv_loop_t* loop,
 }
 
 
+int uv_udp_using_recvmmsg(const uv_udp_t* handle) {
+#if HAVE_MMSG
+  if (handle->flags & UV_HANDLE_UDP_RECVMMSG) {
+    uv_once(&once, uv__udp_mmsg_init);
+    return uv__recvmmsg_avail;
+  }
+#endif
+  return 0;
+}
+
+
 int uv_udp_open(uv_udp_t* handle, uv_os_sock_t sock) {
   int err;
 
@@ -1028,42 +1043,37 @@ int uv_udp_set_source_membership(uv_udp_t* handle,
                                  const char* interface_addr,
                                  const char* source_addr,
                                  uv_membership membership) {
-#if !defined(__OpenBSD__) && !defined(__NetBSD__) && !defined(__ANDROID__)
+#if !defined(__OpenBSD__) &&                                        \
+    !defined(__NetBSD__) &&                                         \
+    !defined(__ANDROID__) &&                                        \
+    !defined(__DragonFly__) &&                                      \
+    !defined(__QNX__)
   int err;
-  struct sockaddr_storage mcast_addr;
-  struct sockaddr_in* mcast_addr4;
-  struct sockaddr_in6* mcast_addr6;
-  struct sockaddr_storage src_addr;
-  struct sockaddr_in* src_addr4;
-  struct sockaddr_in6* src_addr6;
-
-  mcast_addr4 = (struct sockaddr_in*)&mcast_addr;
-  mcast_addr6 = (struct sockaddr_in6*)&mcast_addr;
-  src_addr4 = (struct sockaddr_in*)&src_addr;
-  src_addr6 = (struct sockaddr_in6*)&src_addr;
-
-  err = uv_ip4_addr(multicast_addr, 0, mcast_addr4);
+  union uv__sockaddr mcast_addr;
+  union uv__sockaddr src_addr;
+
+  err = uv_ip4_addr(multicast_addr, 0, &mcast_addr.in);
   if (err) {
-    err = uv_ip6_addr(multicast_addr, 0, mcast_addr6);
+    err = uv_ip6_addr(multicast_addr, 0, &mcast_addr.in6);
     if (err)
       return err;
-    err = uv_ip6_addr(source_addr, 0, src_addr6);
+    err = uv_ip6_addr(source_addr, 0, &src_addr.in6);
     if (err)
       return err;
     return uv__udp_set_source_membership6(handle,
-                                          mcast_addr6,
+                                          &mcast_addr.in6,
                                           interface_addr,
-                                          src_addr6,
+                                          &src_addr.in6,
                                           membership);
   }
 
-  err = uv_ip4_addr(source_addr, 0, src_addr4);
+  err = uv_ip4_addr(source_addr, 0, &src_addr.in);
   if (err)
     return err;
   return uv__udp_set_source_membership4(handle,
-                                        mcast_addr4,
+                                        &mcast_addr.in,
                                         interface_addr,
-                                        src_addr4,
+                                        &src_addr.in,
                                         membership);
 #else
   return UV_ENOSYS;
@@ -1144,7 +1154,7 @@ int uv_udp_set_ttl(uv_udp_t* handle, int ttl) {
  * and use the general uv__setsockopt_maybe_char call on other platforms.
  */
 #if defined(__sun) || defined(_AIX) || defined(__OpenBSD__) || \
-    defined(__MVS__)
+    defined(__MVS__) || defined(__QNX__)
 
   return uv__setsockopt(handle,
                         IP_TTL,
@@ -1153,7 +1163,7 @@ int uv_udp_set_ttl(uv_udp_t* handle, int ttl) {
                         sizeof(ttl));
 
 #else /* !(defined(__sun) || defined(_AIX) || defined (__OpenBSD__) ||
-           defined(__MVS__)) */
+           defined(__MVS__) || defined(__QNX__)) */
 
   return uv__setsockopt_maybe_char(handle,
                                    IP_TTL,
@@ -1161,7 +1171,7 @@ int uv_udp_set_ttl(uv_udp_t* handle, int ttl) {
                                    ttl);
 
 #endif /* defined(__sun) || defined(_AIX) || defined (__OpenBSD__) ||
-          defined(__MVS__) */
+          defined(__MVS__) || defined(__QNX__) */
 }
 
 
@@ -1173,7 +1183,7 @@ int uv_udp_set_multicast_ttl(uv_udp_t* handle, int ttl) {
  * and use the general uv__setsockopt_maybe_char call otherwise.
  */
 #if defined(__sun) || defined(_AIX) || defined(__OpenBSD__) || \
-    defined(__MVS__)
+    defined(__MVS__) || defined(__QNX__)
   if (handle->flags & UV_HANDLE_IPV6)
     return uv__setsockopt(handle,
                           IP_MULTICAST_TTL,
@@ -1181,7 +1191,7 @@ int uv_udp_set_multicast_ttl(uv_udp_t* handle, int ttl) {
                           &ttl,
                           sizeof(ttl));
 #endif /* defined(__sun) || defined(_AIX) || defined(__OpenBSD__) || \
-    defined(__MVS__) */
+    defined(__MVS__) || defined(__QNX__) */
 
   return uv__setsockopt_maybe_char(handle,
                                    IP_MULTICAST_TTL,
@@ -1198,7 +1208,7 @@ int uv_udp_set_multicast_loop(uv_udp_t* handle, int on) {
  * and use the general uv__setsockopt_maybe_char call otherwise.
  */
 #if defined(__sun) || defined(_AIX) || defined(__OpenBSD__) || \
-    defined(__MVS__)
+    defined(__MVS__) || defined(__QNX__)
   if (handle->flags & UV_HANDLE_IPV6)
     return uv__setsockopt(handle,
                           IP_MULTICAST_LOOP,
@@ -1206,7 +1216,7 @@ int uv_udp_set_multicast_loop(uv_udp_t* handle, int on) {
                           &on,
                           sizeof(on));
 #endif /* defined(__sun) || defined(_AIX) ||defined(__OpenBSD__) ||
-    defined(__MVS__) */
+    defined(__MVS__) || defined(__QNX__) */
 
   return uv__setsockopt_maybe_char(handle,
                                    IP_MULTICAST_LOOP,
diff --git a/Utilities/cmlibuv/src/uv-common.c b/Utilities/cmlibuv/src/uv-common.c
index 2fcbe3d61a..f986d75270 100644
--- a/Utilities/cmlibuv/src/uv-common.c
+++ b/Utilities/cmlibuv/src/uv-common.c
@@ -861,11 +861,70 @@ __attribute__((destructor))
 void uv_library_shutdown(void) {
   static int was_shutdown;
 
-  if (was_shutdown)
+  if (uv__load_relaxed(&was_shutdown))
     return;
 
   uv__process_title_cleanup();
   uv__signal_cleanup();
   uv__threadpool_cleanup();
-  was_shutdown = 1;
+  uv__store_relaxed(&was_shutdown, 1);
+}
+
+
+void uv__metrics_update_idle_time(uv_loop_t* loop) {
+  uv__loop_metrics_t* loop_metrics;
+  uint64_t entry_time;
+  uint64_t exit_time;
+
+  if (!(uv__get_internal_fields(loop)->flags & UV_METRICS_IDLE_TIME))
+    return;
+
+  loop_metrics = uv__get_loop_metrics(loop);
+
+  /* The thread running uv__metrics_update_idle_time() is always the same
+   * thread that sets provider_entry_time. So it's unnecessary to lock before
+   * retrieving this value.
+   */
+  if (loop_metrics->provider_entry_time == 0)
+    return;
+
+  exit_time = uv_hrtime();
+
+  uv_mutex_lock(&loop_metrics->lock);
+  entry_time = loop_metrics->provider_entry_time;
+  loop_metrics->provider_entry_time = 0;
+  loop_metrics->provider_idle_time += exit_time - entry_time;
+  uv_mutex_unlock(&loop_metrics->lock);
+}
+
+
+void uv__metrics_set_provider_entry_time(uv_loop_t* loop) {
+  uv__loop_metrics_t* loop_metrics;
+  uint64_t now;
+
+  if (!(uv__get_internal_fields(loop)->flags & UV_METRICS_IDLE_TIME))
+    return;
+
+  now = uv_hrtime();
+  loop_metrics = uv__get_loop_metrics(loop);
+  uv_mutex_lock(&loop_metrics->lock);
+  loop_metrics->provider_entry_time = now;
+  uv_mutex_unlock(&loop_metrics->lock);
+}
+
+
+uint64_t uv_metrics_idle_time(uv_loop_t* loop) {
+  uv__loop_metrics_t* loop_metrics;
+  uint64_t entry_time;
+  uint64_t idle_time;
+
+  loop_metrics = uv__get_loop_metrics(loop);
+  uv_mutex_lock(&loop_metrics->lock);
+  idle_time = loop_metrics->provider_idle_time;
+  entry_time = loop_metrics->provider_entry_time;
+  uv_mutex_unlock(&loop_metrics->lock);
+
+  if (entry_time > 0)
+    idle_time += uv_hrtime() - entry_time;
+  return idle_time;
 }
diff --git a/Utilities/cmlibuv/src/uv-common.h b/Utilities/cmlibuv/src/uv-common.h
index 0b0f5f86a0..e851291cc0 100644
--- a/Utilities/cmlibuv/src/uv-common.h
+++ b/Utilities/cmlibuv/src/uv-common.h
@@ -60,6 +60,14 @@ extern int snprintf(char*, size_t, const char*, ...);
 #define STATIC_ASSERT(expr)                                                   \
   void uv__static_assert(int static_assert_failed[1 - 2 * !(expr)])
 
+#if defined(__GNUC__) && (__GNUC__ > 4 || __GNUC__ == 4 && __GNUC_MINOR__ >= 7)
+#define uv__load_relaxed(p) __atomic_load_n(p, __ATOMIC_RELAXED)
+#define uv__store_relaxed(p, v) __atomic_store_n(p, v, __ATOMIC_RELAXED)
+#else
+#define uv__load_relaxed(p) (*p)
+#define uv__store_relaxed(p, v) do *p = v; while (0)
+#endif
+
 /* Handle flags. Some flags are specific to Windows or UNIX. */
 enum {
   /* Used by all handles. */
@@ -325,6 +333,12 @@ void uv__threadpool_cleanup(void);
   }                                                                           \
   while (0)
 
+#define uv__get_internal_fields(loop)                                         \
+  ((uv__loop_internal_fields_t*) loop->internal_fields)
+
+#define uv__get_loop_metrics(loop)                                            \
+  (&uv__get_internal_fields(loop)->loop_metrics)
+
 /* Allocator prototypes */
 void *uv__calloc(size_t count, size_t size);
 char *uv__strdup(const char* s);
@@ -334,4 +348,21 @@ void uv__free(void* ptr);
 void* uv__realloc(void* ptr, size_t size);
 void* uv__reallocf(void* ptr, size_t size);
 
+typedef struct uv__loop_metrics_s uv__loop_metrics_t;
+typedef struct uv__loop_internal_fields_s uv__loop_internal_fields_t;
+
+struct uv__loop_metrics_s {
+  uint64_t provider_entry_time;
+  uint64_t provider_idle_time;
+  uv_mutex_t lock;
+};
+
+void uv__metrics_update_idle_time(uv_loop_t* loop);
+void uv__metrics_set_provider_entry_time(uv_loop_t* loop);
+
+struct uv__loop_internal_fields_s {
+  unsigned int flags;
+  uv__loop_metrics_t loop_metrics;
+};
+
 #endif /* UV_COMMON_H_ */
diff --git a/Utilities/cmlibuv/src/uv-data-getter-setters.c b/Utilities/cmlibuv/src/uv-data-getter-setters.c
index c3025662fa..0bd0448611 100644
--- a/Utilities/cmlibuv/src/uv-data-getter-setters.c
+++ b/Utilities/cmlibuv/src/uv-data-getter-setters.c
@@ -1,3 +1,24 @@
+/* Copyright libuv project contributors. All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
 #include "uv.h"
 
 const char* uv_handle_type_name(uv_handle_type type) {
diff --git a/Utilities/cmlibuv/src/win/core.c b/Utilities/cmlibuv/src/win/core.c
index 9974a11553..e53a0f8e28 100644
--- a/Utilities/cmlibuv/src/win/core.c
+++ b/Utilities/cmlibuv/src/win/core.c
@@ -222,6 +222,7 @@ static void uv_init(void) {
 
 
 int uv_loop_init(uv_loop_t* loop) {
+  uv__loop_internal_fields_t* lfields;
   struct heap* timer_heap;
   int err;
 
@@ -233,6 +234,15 @@ int uv_loop_init(uv_loop_t* loop) {
   if (loop->iocp == NULL)
     return uv_translate_sys_error(GetLastError());
 
+  lfields = (uv__loop_internal_fields_t*) uv__calloc(1, sizeof(*lfields));
+  if (lfields == NULL)
+    return UV_ENOMEM;
+  loop->internal_fields = lfields;
+
+  err = uv_mutex_init(&lfields->loop_metrics.lock);
+  if (err)
+    goto fail_metrics_mutex_init;
+
   /* To prevent uninitialized memory access, loop->time must be initialized
    * to zero before calling uv_update_time for the first time.
    */
@@ -297,6 +307,11 @@ fail_mutex_init:
   loop->timer_heap = NULL;
 
 fail_timers_alloc:
+  uv_mutex_destroy(&lfields->loop_metrics.lock);
+
+fail_metrics_mutex_init:
+  uv__free(lfields);
+  loop->internal_fields = NULL;
   CloseHandle(loop->iocp);
   loop->iocp = INVALID_HANDLE_VALUE;
 
@@ -317,6 +332,7 @@ void uv__once_init(void) {
 
 
 void uv__loop_close(uv_loop_t* loop) {
+  uv__loop_internal_fields_t* lfields;
   size_t i;
 
   uv__loops_remove(loop);
@@ -347,11 +363,24 @@ void uv__loop_close(uv_loop_t* loop) {
   uv__free(loop->timer_heap);
   loop->timer_heap = NULL;
 
+  lfields = uv__get_internal_fields(loop);
+  uv_mutex_destroy(&lfields->loop_metrics.lock);
+  uv__free(lfields);
+  loop->internal_fields = NULL;
+
   CloseHandle(loop->iocp);
 }
 
 
 int uv__loop_configure(uv_loop_t* loop, uv_loop_option option, va_list ap) {
+  uv__loop_internal_fields_t* lfields;
+
+  lfields = uv__get_internal_fields(loop);
+  if (option == UV_METRICS_IDLE_TIME) {
+    lfields->flags |= UV_METRICS_IDLE_TIME;
+    return 0;
+  }
+
   return UV_ENOSYS;
 }
 
@@ -393,16 +422,44 @@ static void uv__poll_wine(uv_loop_t* loop, DWORD timeout) {
   uv_req_t* req;
   int repeat;
   uint64_t timeout_time;
+  uint64_t user_timeout;
+  int reset_timeout;
 
   timeout_time = loop->time + timeout;
 
+  if (uv__get_internal_fields(loop)->flags & UV_METRICS_IDLE_TIME) {
+    reset_timeout = 1;
+    user_timeout = timeout;
+    timeout = 0;
+  } else {
+    reset_timeout = 0;
+  }
+
   for (repeat = 0; ; repeat++) {
+    /* Only need to set the provider_entry_time if timeout != 0. The function
+     * will return early if the loop isn't configured with UV_METRICS_IDLE_TIME.
+     */
+    if (timeout != 0)
+      uv__metrics_set_provider_entry_time(loop);
+
     GetQueuedCompletionStatus(loop->iocp,
                               &bytes,
                               &key,
                               &overlapped,
                               timeout);
 
+    if (reset_timeout != 0) {
+      timeout = user_timeout;
+      reset_timeout = 0;
+    }
+
+    /* Placed here because on success the loop will break whether there is an
+     * empty package or not, or if GetQueuedCompletionStatus returned early then
+     * the timeout will be updated and the loop will run again. In either case
+     * the idle time will need to be updated.
+     */
+    uv__metrics_update_idle_time(loop);
+
     if (overlapped) {
       /* Package was dequeued */
       req = uv_overlapped_to_req(overlapped);
@@ -445,10 +502,26 @@ static void uv__poll(uv_loop_t* loop, DWORD timeout) {
   ULONG i;
   int repeat;
   uint64_t timeout_time;
+  uint64_t user_timeout;
+  int reset_timeout;
 
   timeout_time = loop->time + timeout;
 
+  if (uv__get_internal_fields(loop)->flags & UV_METRICS_IDLE_TIME) {
+    reset_timeout = 1;
+    user_timeout = timeout;
+    timeout = 0;
+  } else {
+    reset_timeout = 0;
+  }
+
   for (repeat = 0; ; repeat++) {
+    /* Only need to set the provider_entry_time if timeout != 0. The function
+     * will return early if the loop isn't configured with UV_METRICS_IDLE_TIME.
+     */
+    if (timeout != 0)
+      uv__metrics_set_provider_entry_time(loop);
+
     success = pGetQueuedCompletionStatusEx(loop->iocp,
                                            overlappeds,
                                            ARRAY_SIZE(overlappeds),
@@ -456,6 +529,18 @@ static void uv__poll(uv_loop_t* loop, DWORD timeout) {
                                            timeout,
                                            FALSE);
 
+    if (reset_timeout != 0) {
+      timeout = user_timeout;
+      reset_timeout = 0;
+    }
+
+    /* Placed here because on success the loop will break whether there is an
+     * empty package or not, or if GetQueuedCompletionStatus returned early then
+     * the timeout will be updated and the loop will run again. In either case
+     * the idle time will need to be updated.
+     */
+    uv__metrics_update_idle_time(loop);
+
     if (success) {
       for (i = 0; i < count; i++) {
         /* Package was dequeued, but see if it is not a empty package
@@ -534,6 +619,12 @@ int uv_run(uv_loop_t *loop, uv_run_mode mode) {
     else
       uv__poll_wine(loop, timeout);
 
+    /* Run one final update on the provider_idle_time in case uv__poll*
+     * returned because the timeout expired, but no events were received. This
+     * call will be ignored if the provider_entry_time was either never set (if
+     * the timeout == 0) or was already updated b/c an event was received.
+     */
+    uv__metrics_update_idle_time(loop);
 
     uv_check_invoke(loop);
     uv_process_endgames(loop);
diff --git a/Utilities/cmlibuv/src/win/detect-wakeup.c b/Utilities/cmlibuv/src/win/detect-wakeup.c
index 72dfb7a177..ab19361578 100644
--- a/Utilities/cmlibuv/src/win/detect-wakeup.c
+++ b/Utilities/cmlibuv/src/win/detect-wakeup.c
@@ -1,3 +1,24 @@
+/* Copyright libuv project contributors. All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
 #include "uv.h"
 #include "internal.h"
 #include "winapi.h"
diff --git a/Utilities/cmlibuv/src/win/fs-fd-hash-inl.h b/Utilities/cmlibuv/src/win/fs-fd-hash-inl.h
index 7a203d232d..0b532af12d 100644
--- a/Utilities/cmlibuv/src/win/fs-fd-hash-inl.h
+++ b/Utilities/cmlibuv/src/win/fs-fd-hash-inl.h
@@ -1,3 +1,24 @@
+/* Copyright libuv project contributors. All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
 #ifndef UV_WIN_FS_FD_HASH_INL_H_
 #define UV_WIN_FS_FD_HASH_INL_H_
 
@@ -53,7 +74,8 @@ static struct uv__fd_hash_bucket_s uv__fd_hash[UV__FD_HASH_SIZE];
 
 
 INLINE static void uv__fd_hash_init(void) {
-  int i, err;
+  size_t i;
+  int err;
 
   err = uv_mutex_init(&uv__fd_hash_mutex);
   if (err) {
diff --git a/Utilities/cmlibuv/src/win/fs.c b/Utilities/cmlibuv/src/win/fs.c
index 9577bc02d3..8a801749d4 100644
--- a/Utilities/cmlibuv/src/win/fs.c
+++ b/Utilities/cmlibuv/src/win/fs.c
@@ -70,10 +70,7 @@
 #define SET_REQ_RESULT(req, result_value)                                   \
   do {                                                                      \
     req->result = (result_value);                                           \
-    if (req->result == -1) {                                                \
-      req->sys_errno_ = _doserrno;                                          \
-      req->result = uv_translate_sys_error(req->sys_errno_);                \
-    }                                                                       \
+    assert(req->result != -1);                                              \
   } while (0)
 
 #define SET_REQ_WIN32_ERROR(req, sys_errno)                                 \
@@ -730,14 +727,14 @@ void fs__close(uv_fs_t* req) {
     assert(errno == EBADF);
     SET_REQ_UV_ERROR(req, UV_EBADF, ERROR_INVALID_HANDLE);
   } else {
-    req->result = 0;
+    SET_REQ_RESULT(req, 0);
   }
 }
 
 
 LONG fs__filemap_ex_filter(LONG excode, PEXCEPTION_POINTERS pep,
                            int* perror) {
-  if (excode != EXCEPTION_IN_PAGE_ERROR) {
+  if (excode != (LONG)EXCEPTION_IN_PAGE_ERROR) {
     return EXCEPTION_CONTINUE_SEARCH;
   }
 
@@ -816,10 +813,10 @@ void fs__read_filemap(uv_fs_t* req, struct uv__fd_info_s* fd_info) {
   for (index = 0;
        index < req->fs.info.nbufs && done_read < read_size;
        ++index) {
-    int err = 0;
     size_t this_read_size = MIN(req->fs.info.bufs[index].len,
                                 read_size - done_read);
 #ifdef _MSC_VER
+    int err = 0;
     __try {
 #endif
       memcpy(req->fs.info.bufs[index].base,
@@ -938,7 +935,7 @@ void fs__write_filemap(uv_fs_t* req, HANDLE file,
     (UV_FS_O_RDONLY | UV_FS_O_WRONLY | UV_FS_O_RDWR);
   size_t write_size, done_write;
   unsigned int index;
-  LARGE_INTEGER zero, pos, end_pos;
+  LARGE_INTEGER pos, end_pos;
   size_t view_offset;
   LARGE_INTEGER view_base;
   void* view;
@@ -963,7 +960,6 @@ void fs__write_filemap(uv_fs_t* req, HANDLE file,
     return;
   }
 
-  zero.QuadPart = 0;
   if (force_append) {
     pos = fd_info->size;
   } else if (req->fs.info.offset == -1) {
@@ -1014,8 +1010,8 @@ void fs__write_filemap(uv_fs_t* req, HANDLE file,
 
   done_write = 0;
   for (index = 0; index < req->fs.info.nbufs; ++index) {
-    int err = 0;
 #ifdef _MSC_VER
+    int err = 0;
     __try {
 #endif
       memcpy((char*)view + view_offset + done_write,
@@ -1128,7 +1124,10 @@ void fs__write(uv_fs_t* req) {
 
 void fs__rmdir(uv_fs_t* req) {
   int result = _wrmdir(req->file.pathw);
-  SET_REQ_RESULT(req, result);
+  if (result == -1)
+    SET_REQ_WIN32_ERROR(req, _doserrno);
+  else
+    SET_REQ_RESULT(req, 0);
 }
 
 
@@ -1221,12 +1220,12 @@ void fs__unlink(uv_fs_t* req) {
 
 void fs__mkdir(uv_fs_t* req) {
   /* TODO: use req->mode. */
-  req->result = _wmkdir(req->file.pathw);
-  if (req->result == -1) {
-    req->sys_errno_ = _doserrno;
-    req->result = req->sys_errno_ == ERROR_INVALID_NAME
-                ? UV_EINVAL
-                : uv_translate_sys_error(req->sys_errno_);
+  if (CreateDirectoryW(req->file.pathw, NULL)) {
+    SET_REQ_RESULT(req, 0);
+  } else {
+    SET_REQ_WIN32_ERROR(req, GetLastError());
+    if (req->sys_errno_ == ERROR_INVALID_NAME)
+      req->result = UV_EINVAL;
   }
 }
 
@@ -1242,19 +1241,21 @@ void fs__mktemp(uv_fs_t* req, uv__fs_mktemp_func func) {
   unsigned int tries, i;
   size_t len;
   uint64_t v;
-
+  char* path;
+  
+  path = req->path;
   len = wcslen(req->file.pathw);
   ep = req->file.pathw + len;
   if (len < num_x || wcsncmp(ep - num_x, L"XXXXXX", num_x)) {
     SET_REQ_UV_ERROR(req, UV_EINVAL, ERROR_INVALID_PARAMETER);
-    return;
+    goto clobber;
   }
 
   tries = TMP_MAX;
   do {
     if (uv__random_rtlgenrandom((void *)&v, sizeof(v)) < 0) {
       SET_REQ_UV_ERROR(req, UV_EIO, ERROR_IO_DEVICE);
-      break;
+      goto clobber;
     }
 
     cp = ep - num_x;
@@ -1265,25 +1266,29 @@ void fs__mktemp(uv_fs_t* req, uv__fs_mktemp_func func) {
 
     if (func(req)) {
       if (req->result >= 0) {
-        len = strlen(req->path);
-        wcstombs((char*) req->path + len - num_x, ep - num_x, num_x);
+        len = strlen(path);
+        wcstombs(path + len - num_x, ep - num_x, num_x);
       }
-      break;
+      return;
     }
   } while (--tries);
 
-  if (tries == 0) {
-    SET_REQ_RESULT(req, -1);
-  }
+  SET_REQ_WIN32_ERROR(req, GetLastError());
+
+clobber:
+  path[0] = '\0';
 }
 
 
 static int fs__mkdtemp_func(uv_fs_t* req) {
-  if (_wmkdir(req->file.pathw) == 0) {
+  DWORD error;
+  if (CreateDirectoryW(req->file.pathw, NULL)) {
     SET_REQ_RESULT(req, 0);
     return 1;
-  } else if (errno != EEXIST) {
-    SET_REQ_RESULT(req, -1);
+  }
+  error = GetLastError();
+  if (error != ERROR_ALREADY_EXISTS) {
+    SET_REQ_WIN32_ERROR(req, error);
     return 1;
   }
 
@@ -1404,7 +1409,7 @@ void fs__scandir(uv_fs_t* req) {
   /* If the handle is not a directory, we'll get STATUS_INVALID_PARAMETER.
    * This should be reported back as UV_ENOTDIR.
    */
-  if (status == STATUS_INVALID_PARAMETER)
+  if (status == (NTSTATUS)STATUS_INVALID_PARAMETER)
     goto not_a_directory_error;
 
   while (NT_SUCCESS(status)) {
@@ -1895,7 +1900,7 @@ INLINE static void fs__stat_impl(uv_fs_t* req, int do_lstat) {
   }
 
   req->ptr = &req->statbuf;
-  req->result = 0;
+  SET_REQ_RESULT(req, 0);
 }
 
 
@@ -1930,7 +1935,7 @@ static void fs__fstat(uv_fs_t* req) {
   }
 
   req->ptr = &req->statbuf;
-  req->result = 0;
+  SET_REQ_RESULT(req, 0);
 }
 
 
@@ -2157,7 +2162,10 @@ static void fs__access(uv_fs_t* req) {
 
 static void fs__chmod(uv_fs_t* req) {
   int result = _wchmod(req->file.pathw, req->fs.info.mode);
-  SET_REQ_RESULT(req, result);
+  if (result == -1)
+    SET_REQ_WIN32_ERROR(req, _doserrno);
+  else
+    SET_REQ_RESULT(req, 0);
 }
 
 
@@ -2315,7 +2323,7 @@ INLINE static void fs__utime_impl(uv_fs_t* req, int do_lutime) {
     return;
   }
 
-  req->result = 0;
+  SET_REQ_RESULT(req, 0);
 }
 
 static void fs__utime(uv_fs_t* req) {
@@ -2340,7 +2348,7 @@ static void fs__futime(uv_fs_t* req) {
     return;
   }
 
-  req->result = 0;
+  SET_REQ_RESULT(req, 0);
 }
 
 static void fs__lutime(uv_fs_t* req) {
@@ -2350,11 +2358,10 @@ static void fs__lutime(uv_fs_t* req) {
 
 static void fs__link(uv_fs_t* req) {
   DWORD r = CreateHardLinkW(req->fs.info.new_pathw, req->file.pathw, NULL);
-  if (r == 0) {
+  if (r == 0)
     SET_REQ_WIN32_ERROR(req, GetLastError());
-  } else {
-    req->result = 0;
-  }
+  else
+    SET_REQ_RESULT(req, 0);
 }
 
 
@@ -2674,17 +2681,17 @@ static void fs__realpath(uv_fs_t* req) {
 
 
 static void fs__chown(uv_fs_t* req) {
-  req->result = 0;
+  SET_REQ_RESULT(req, 0);
 }
 
 
 static void fs__fchown(uv_fs_t* req) {
-  req->result = 0;
+  SET_REQ_RESULT(req, 0);
 }
 
 
 static void fs__lchown(uv_fs_t* req) {
-  req->result = 0;
+  SET_REQ_RESULT(req, 0);
 }
 
 
@@ -2829,7 +2836,7 @@ static void uv__fs_done(struct uv__work* w, int status) {
 
   if (status == UV_ECANCELED) {
     assert(req->result == 0);
-    req->result = UV_ECANCELED;
+    SET_REQ_UV_ERROR(req, UV_ECANCELED, 0);
   }
 
   req->cb(req);
diff --git a/Utilities/cmlibuv/src/win/internal.h b/Utilities/cmlibuv/src/win/internal.h
index 463ef33d63..3f56777c61 100644
--- a/Utilities/cmlibuv/src/win/internal.h
+++ b/Utilities/cmlibuv/src/win/internal.h
@@ -270,7 +270,7 @@ void uv__fs_poll_endgame(uv_loop_t* loop, uv_fs_poll_t* handle);
  */
 void uv__util_init(void);
 
-uint64_t uv__hrtime(double scale);
+uint64_t uv__hrtime(unsigned int scale);
 __declspec(noreturn) void uv_fatal_error(const int errorno, const char* syscall);
 int uv__getpwuid_r(uv_passwd_t* pwd);
 int uv__convert_utf16_to_utf8(const WCHAR* utf16, int utf16len, char** utf8);
diff --git a/Utilities/cmlibuv/src/win/pipe.c b/Utilities/cmlibuv/src/win/pipe.c
index fc0112a33c..f81245ec60 100644
--- a/Utilities/cmlibuv/src/win/pipe.c
+++ b/Utilities/cmlibuv/src/win/pipe.c
@@ -244,9 +244,8 @@ int uv_stdio_pipe_server(uv_loop_t* loop, uv_pipe_t* handle, DWORD access,
   return 0;
 
  error:
-  if (pipeHandle != INVALID_HANDLE_VALUE) {
+  if (pipeHandle != INVALID_HANDLE_VALUE)
     CloseHandle(pipeHandle);
-  }
 
   return err;
 }
@@ -554,7 +553,7 @@ int uv_pipe_bind(uv_pipe_t* handle, const char* name) {
 
   /* Convert name to UTF16. */
   nameSize = MultiByteToWideChar(CP_UTF8, 0, name, -1, NULL, 0) * sizeof(WCHAR);
-  handle->name = (WCHAR*)uv__malloc(nameSize);
+  handle->name = uv__malloc(nameSize);
   if (!handle->name) {
     uv_fatal_error(ERROR_OUTOFMEMORY, "uv__malloc");
   }
@@ -621,9 +620,8 @@ static DWORD WINAPI pipe_connect_thread_proc(void* parameter) {
   while (WaitNamedPipeW(handle->name, 30000)) {
     /* The pipe is now available, try to connect. */
     pipeHandle = open_named_pipe(handle->name, &duplex_flags);
-    if (pipeHandle != INVALID_HANDLE_VALUE) {
+    if (pipeHandle != INVALID_HANDLE_VALUE)
       break;
-    }
 
     SwitchToThread();
   }
@@ -655,7 +653,7 @@ void uv_pipe_connect(uv_connect_t* req, uv_pipe_t* handle,
 
   /* Convert name to UTF16. */
   nameSize = MultiByteToWideChar(CP_UTF8, 0, name, -1, NULL, 0) * sizeof(WCHAR);
-  handle->name = (WCHAR*)uv__malloc(nameSize);
+  handle->name = uv__malloc(nameSize);
   if (!handle->name) {
     uv_fatal_error(ERROR_OUTOFMEMORY, "uv__malloc");
   }
@@ -2147,7 +2145,7 @@ int uv_pipe_open(uv_pipe_t* pipe, uv_file file) {
   if (pipe->ipc) {
     assert(!(pipe->flags & UV_HANDLE_NON_OVERLAPPED_PIPE));
     pipe->pipe.conn.ipc_remote_pid = uv_os_getppid();
-    assert(pipe->pipe.conn.ipc_remote_pid != (DWORD) -1);
+    assert(pipe->pipe.conn.ipc_remote_pid != (DWORD)(uv_pid_t) -1);
   }
   return 0;
 }
diff --git a/Utilities/cmlibuv/src/win/tcp.c b/Utilities/cmlibuv/src/win/tcp.c
index 941c8010d3..0dcaa97df7 100644
--- a/Utilities/cmlibuv/src/win/tcp.c
+++ b/Utilities/cmlibuv/src/win/tcp.c
@@ -523,16 +523,15 @@ static void uv_tcp_queue_read(uv_loop_t* loop, uv_tcp_t* handle) {
                    &req->u.io.overlapped,
                    NULL);
 
+  handle->flags |= UV_HANDLE_READ_PENDING;
+  handle->reqs_pending++;
+
   if (UV_SUCCEEDED_WITHOUT_IOCP(result == 0)) {
     /* Process the req without IOCP. */
-    handle->flags |= UV_HANDLE_READ_PENDING;
     req->u.io.overlapped.InternalHigh = bytes;
-    handle->reqs_pending++;
     uv_insert_pending_req(loop, (uv_req_t*)req);
   } else if (UV_SUCCEEDED_WITH_IOCP(result == 0)) {
     /* The req will be processed with IOCP. */
-    handle->flags |= UV_HANDLE_READ_PENDING;
-    handle->reqs_pending++;
     if (handle->flags & UV_HANDLE_EMULATE_IOCP &&
         req->wait_handle == INVALID_HANDLE_VALUE &&
         !RegisterWaitForSingleObject(&req->wait_handle,
@@ -545,7 +544,6 @@ static void uv_tcp_queue_read(uv_loop_t* loop, uv_tcp_t* handle) {
     /* Make this req pending reporting an error. */
     SET_REQ_ERROR(req, WSAGetLastError());
     uv_insert_pending_req(loop, (uv_req_t*)req);
-    handle->reqs_pending++;
   }
 }
 
@@ -750,6 +748,40 @@ int uv_tcp_read_start(uv_tcp_t* handle, uv_alloc_cb alloc_cb,
   return 0;
 }
 
+static int uv__is_loopback(const struct sockaddr_storage* storage) {
+  const struct sockaddr_in* in4;
+  const struct sockaddr_in6* in6;
+  int i;
+
+  if (storage->ss_family == AF_INET) {
+    in4 = (const struct sockaddr_in*) storage;
+    return in4->sin_addr.S_un.S_un_b.s_b1 == 127;
+  }
+  if (storage->ss_family == AF_INET6) {
+    in6 = (const struct sockaddr_in6*) storage;
+    for (i = 0; i < 7; ++i) {
+      if (in6->sin6_addr.u.Word[i] != 0)
+        return 0;
+    }
+    return in6->sin6_addr.u.Word[7] == htons(1);
+  }
+  return 0;
+}
+
+// Check if Windows version is 10.0.16299 or later
+static int uv__is_fast_loopback_fail_supported() {
+  OSVERSIONINFOW os_info;
+  if (!pRtlGetVersion)
+    return 0;
+  pRtlGetVersion(&os_info);
+  if (os_info.dwMajorVersion < 10)
+    return 0;
+  if (os_info.dwMajorVersion > 10)
+    return 1;
+  if (os_info.dwMinorVersion > 0)
+    return 1;
+  return os_info.dwBuildNumber >= 16299;
+}
 
 static int uv_tcp_try_connect(uv_connect_t* req,
                               uv_tcp_t* handle,
@@ -757,6 +789,7 @@ static int uv_tcp_try_connect(uv_connect_t* req,
                               unsigned int addrlen,
                               uv_connect_cb cb) {
   uv_loop_t* loop = handle->loop;
+  TCP_INITIAL_RTO_PARAMETERS retransmit_ioctl;
   const struct sockaddr* bind_addr;
   struct sockaddr_storage converted;
   BOOL success;
@@ -792,6 +825,25 @@ static int uv_tcp_try_connect(uv_connect_t* req,
     }
   }
 
+  /* This makes connect() fail instantly if the target port on the localhost
+   * is not reachable, instead of waiting for 2s. We do not care if this fails.
+   * This only works on Windows version 10.0.16299 and later.
+   */
+  if (uv__is_fast_loopback_fail_supported() && uv__is_loopback(&converted)) {
+    memset(&retransmit_ioctl, 0, sizeof(retransmit_ioctl));
+    retransmit_ioctl.Rtt = TCP_INITIAL_RTO_NO_SYN_RETRANSMISSIONS;
+    retransmit_ioctl.MaxSynRetransmissions = TCP_INITIAL_RTO_NO_SYN_RETRANSMISSIONS;
+    WSAIoctl(handle->socket,
+             SIO_TCP_INITIAL_RTO,
+             &retransmit_ioctl,
+             sizeof(retransmit_ioctl),
+             NULL,
+             0,
+             &bytes,
+             NULL,
+             NULL);
+  }
+
   UV_REQ_INIT(req, UV_CONNECT);
   req->handle = (uv_stream_t*) handle;
   req->cb = cb;
diff --git a/Utilities/cmlibuv/src/win/tty.c b/Utilities/cmlibuv/src/win/tty.c
index 488d9b2a14..1b9d4f8532 100644
--- a/Utilities/cmlibuv/src/win/tty.c
+++ b/Utilities/cmlibuv/src/win/tty.c
@@ -517,6 +517,7 @@ static DWORD CALLBACK uv_tty_line_read_thread(void* data) {
   status = InterlockedExchange(&uv__read_console_status, IN_PROGRESS);
   if (status == TRAP_REQUESTED) {
     SET_REQ_SUCCESS(req);
+    InterlockedExchange(&uv__read_console_status, COMPLETED);
     req->u.io.overlapped.InternalHigh = 0;
     POST_COMPLETION_FOR_REQ(loop, req);
     return 0;
@@ -2121,13 +2122,6 @@ static int uv_tty_write_bufs(uv_tty_t* handle,
         abort();
       }
 
-      /* We wouldn't mind emitting utf-16 surrogate pairs. Too bad, the windows
-       * console doesn't really support UTF-16, so just emit the replacement
-       * character. */
-      if (utf8_codepoint > 0xffff) {
-        utf8_codepoint = UNICODE_REPLACEMENT_CHARACTER;
-      }
-
       if (utf8_codepoint == 0x0a || utf8_codepoint == 0x0d) {
         /* EOL conversion - emit \r\n when we see \n. */
 
@@ -2154,6 +2148,12 @@ static int uv_tty_write_bufs(uv_tty_t* handle,
         ENSURE_BUFFER_SPACE(1);
         utf16_buf[utf16_buf_used++] = (WCHAR) utf8_codepoint;
         previous_eol = 0;
+      } else {
+        ENSURE_BUFFER_SPACE(2);
+        utf8_codepoint -= 0x10000;
+        utf16_buf[utf16_buf_used++] = (WCHAR) (utf8_codepoint / 0x400 + 0xD800);
+        utf16_buf[utf16_buf_used++] = (WCHAR) (utf8_codepoint % 0x400 + 0xDC00);
+        previous_eol = 0;
       }
     }
   }
@@ -2412,6 +2412,7 @@ static DWORD WINAPI uv__tty_console_resize_watcher_thread(void* param) {
     uv__tty_console_signal_resize();
     ResetEvent(uv__tty_console_resized);
   }
+  return 0;
 }
 
 static void uv__tty_console_signal_resize(void) {
diff --git a/Utilities/cmlibuv/src/win/udp.c b/Utilities/cmlibuv/src/win/udp.c
index 508ed37fb7..68ca728aa5 100644
--- a/Utilities/cmlibuv/src/win/udp.c
+++ b/Utilities/cmlibuv/src/win/udp.c
@@ -189,6 +189,11 @@ void uv_udp_endgame(uv_loop_t* loop, uv_udp_t* handle) {
 }
 
 
+int uv_udp_using_recvmmsg(const uv_udp_t* handle) {
+  return 0;
+}
+
+
 static int uv_udp_maybe_bind(uv_udp_t* handle,
                              const struct sockaddr* addr,
                              unsigned int addrlen,
@@ -752,6 +757,9 @@ int uv__udp_set_source_membership6(uv_udp_t* handle,
   int optname;
   int err;
 
+  STATIC_ASSERT(sizeof(mreq.gsr_group) >= sizeof(*multicast_addr));
+  STATIC_ASSERT(sizeof(mreq.gsr_source) >= sizeof(*source_addr));
+
   if ((handle->flags & UV_HANDLE_BOUND) && !(handle->flags & UV_HANDLE_IPV6))
     return UV_EINVAL;
 
@@ -774,8 +782,8 @@ int uv__udp_set_source_membership6(uv_udp_t* handle,
     mreq.gsr_interface = 0;
   }
 
-  memcpy(&mreq.gsr_group, multicast_addr, sizeof(mreq.gsr_group));
-  memcpy(&mreq.gsr_source, source_addr, sizeof(mreq.gsr_source));
+  memcpy(&mreq.gsr_group, multicast_addr, sizeof(*multicast_addr));
+  memcpy(&mreq.gsr_source, source_addr, sizeof(*source_addr));
 
   if (membership == UV_JOIN_GROUP)
     optname = MCAST_JOIN_SOURCE_GROUP;
@@ -1065,7 +1073,7 @@ int uv__udp_connect(uv_udp_t* handle,
 
   err = connect(handle->socket, addr, addrlen);
   if (err)
-    return uv_translate_sys_error(err);
+    return uv_translate_sys_error(WSAGetLastError());
 
   handle->flags |= UV_HANDLE_UDP_CONNECTED;
 
@@ -1081,7 +1089,7 @@ int uv__udp_disconnect(uv_udp_t* handle) {
 
     err = connect(handle->socket, &addr, sizeof(addr));
     if (err)
-      return uv_translate_sys_error(err);
+      return uv_translate_sys_error(WSAGetLastError());
 
     handle->flags &= ~UV_HANDLE_UDP_CONNECTED;
     return 0;
diff --git a/Utilities/cmlibuv/src/win/util.c b/Utilities/cmlibuv/src/win/util.c
index 9e1e7f73e3..aad8f1a15e 100644
--- a/Utilities/cmlibuv/src/win/util.c
+++ b/Utilities/cmlibuv/src/win/util.c
@@ -30,12 +30,14 @@
 #include "uv.h"
 #include "internal.h"
 
+/* clang-format off */
 #include <winsock2.h>
 #include <winperf.h>
 #include <iphlpapi.h>
 #include <psapi.h>
 #include <tlhelp32.h>
 #include <windows.h>
+/* clang-format on */
 #include <userenv.h>
 #include <math.h>
 
@@ -67,8 +69,8 @@ extern BOOLEAN NTAPI SystemFunction036(PVOID Buffer, ULONG BufferLength);
 static char *process_title;
 static CRITICAL_SECTION process_title_lock;
 
-/* Interval (in seconds) of the high-resolution clock. */
-static double hrtime_interval_ = 0;
+/* Frequency of the high-resolution clock. */
+static uint64_t hrtime_frequency_ = 0;
 
 
 /*
@@ -84,9 +86,9 @@ void uv__util_init(void) {
    * and precompute its reciprocal.
    */
   if (QueryPerformanceFrequency(&perf_frequency)) {
-    hrtime_interval_ = 1.0 / perf_frequency.QuadPart;
+    hrtime_frequency_ = perf_frequency.QuadPart;
   } else {
-    hrtime_interval_= 0;
+    uv_fatal_error(GetLastError(), "QueryPerformanceFrequency");
   }
 }
 
@@ -490,23 +492,25 @@ uint64_t uv_hrtime(void) {
   return uv__hrtime(UV__NANOSEC);
 }
 
-uint64_t uv__hrtime(double scale) {
+uint64_t uv__hrtime(unsigned int scale) {
   LARGE_INTEGER counter;
+  double scaled_freq;
+  double result;
 
-  /* If the performance interval is zero, there's no support. */
-  if (hrtime_interval_ == 0) {
-    return 0;
-  }
-
+  assert(hrtime_frequency_ != 0);
+  assert(scale != 0);
   if (!QueryPerformanceCounter(&counter)) {
-    return 0;
+    uv_fatal_error(GetLastError(), "QueryPerformanceCounter");
   }
+  assert(counter.QuadPart != 0);
 
   /* Because we have no guarantee about the order of magnitude of the
    * performance counter interval, integer math could cause this computation
    * to overflow. Therefore we resort to floating point math.
    */
-  return (uint64_t) ((double) counter.QuadPart * hrtime_interval_ * scale);
+  scaled_freq = (double) hrtime_frequency_ / scale;
+  result = (double) counter.QuadPart / scaled_freq;
+  return (uint64_t) result;
 }
 
 
@@ -1804,7 +1808,9 @@ int uv_os_uname(uv_utsname_t* buffer) {
     pRtlGetVersion(&os_info);
   } else {
     /* Silence GetVersionEx() deprecation warning. */
+    #ifdef _MSC_VER
     #pragma warning(suppress : 4996)
+    #endif
     if (GetVersionExW(&os_info) == 0) {
       r = uv_translate_sys_error(GetLastError());
       goto error;
@@ -1871,7 +1877,7 @@ int uv_os_uname(uv_utsname_t* buffer) {
                "MINGW32_NT-%u.%u",
                (unsigned int) os_info.dwMajorVersion,
                (unsigned int) os_info.dwMinorVersion);
-  assert(r < sizeof(buffer->sysname));
+  assert((size_t)r < sizeof(buffer->sysname));
 #else
   uv__strscpy(buffer->sysname, "Windows_NT", sizeof(buffer->sysname));
 #endif
@@ -1883,7 +1889,7 @@ int uv_os_uname(uv_utsname_t* buffer) {
                (unsigned int) os_info.dwMajorVersion,
                (unsigned int) os_info.dwMinorVersion,
                (unsigned int) os_info.dwBuildNumber);
-  assert(r < sizeof(buffer->release));
+  assert((size_t)r < sizeof(buffer->release));
 
   /* Populate the machine field. */
   GetSystemInfo(&system_info);
diff --git a/Utilities/cmlibuv/src/win/winapi.h b/Utilities/cmlibuv/src/win/winapi.h
index 77f1878716..9bc455934a 100644
--- a/Utilities/cmlibuv/src/win/winapi.h
+++ b/Utilities/cmlibuv/src/win/winapi.h
@@ -4735,6 +4735,18 @@ typedef HWINEVENTHOOK (WINAPI *sSetWinEventHook)
                        DWORD        idThread,
                        UINT         dwflags);
 
+/* From mstcpip.h */
+typedef struct _TCP_INITIAL_RTO_PARAMETERS {
+  USHORT Rtt;
+  UCHAR  MaxSynRetransmissions;
+} TCP_INITIAL_RTO_PARAMETERS, *PTCP_INITIAL_RTO_PARAMETERS;
+
+#ifndef TCP_INITIAL_RTO_NO_SYN_RETRANSMISSIONS
+# define TCP_INITIAL_RTO_NO_SYN_RETRANSMISSIONS ((UCHAR) -2)
+#endif
+#ifndef SIO_TCP_INITIAL_RTO
+# define  SIO_TCP_INITIAL_RTO _WSAIOW(IOC_VENDOR,17)
+#endif
 
 /* Ntdll function pointers */
 extern sRtlGetVersion pRtlGetVersion;