tests: check whether epoll_wait() timeout is reliable and adjust justsleep().

* configure.in:
  Small epoll_wait() loop to check timeout reliability and set
  HAVE_EPOLL_WAIT_RELIABLE_TIMEOUT.

* test/testpoll.c(justsleep):
  Allow some jiffy is !HAVE_EPOLL_WAIT_RELIABLE_TIMEOUT.



git-svn-id: https://svn.apache.org/repos/asf/apr/apr/trunk@1908616 13f79535-47bb-0310-9956-ffa450edef68

1 files changed, 43 insertions, 2 deletions

diff --git a/configure.in b/configure.in
index 9e828ec6a..2225cb0a4 100644
--- a/configure.in
+++ b/configure.in
@@ -1099,7 +1099,7 @@ AC_CACHE_CHECK([for epoll support], [apr_cv_epoll],
 #include <sys/epoll.h>
 #include <unistd.h>
 
-int main()
+int main(int argc, const char *argv[])
 {
     return epoll_create(5) == -1;
 }], [apr_cv_epoll=yes], [apr_cv_epoll=no], [apr_cv_epoll=no])])
@@ -1115,7 +1115,7 @@ AC_CACHE_CHECK([for epoll_create1 support], [apr_cv_epoll_create1],
 #include <sys/epoll.h>
 #include <unistd.h>
 
-int main()
+int main(int argc, const char *argv[])
 {
     return epoll_create1(0) == -1;
 }], [apr_cv_epoll_create1=yes], [apr_cv_epoll_create1=no], [apr_cv_epoll_create1=no])])
@@ -1124,6 +1124,47 @@ if test "$apr_cv_epoll_create1" = "yes"; then
    AC_DEFINE([HAVE_EPOLL_CREATE1], 1, [Define if epoll_create1 function is supported])
 fi
 
+# check if epoll_wait() timeout is a reliable as min min
+AC_CACHE_CHECK([whether epoll_wait has a reliable timeout (min)],
+               [apr_cv_epoll_wait_has_reliable_timeout],
+[AC_TRY_RUN([
+#include <unistd.h>
+#include <sys/epoll.h>
+#include <sys/time.h>   /* for gettimeofday */
+
+#define TV2US(tv) ((long long)(tv).tv_sec * 1000000 + (tv).tv_usec)
+
+int main(int argc, const char *argv[])
+{
+    int ret = 0, fd, i;
+    struct epoll_event events;
+    struct timeval t1, t2;
+
+#ifdef HAVE_EPOLL_CREATE1
+    fd = epoll_create1(0);
+#else
+    fd = epoll_create(1);
+#endif
+    if (fd < 0) {
+        return 1;
+    }
+    for (i = 0; i < 10; ++i) {
+        (void)gettimeofday(&t1, NULL);
+        (void)epoll_wait(fd, &events, 1, 100);   /* ms */
+        (void)gettimeofday(&t2, NULL);
+        ret |= (TV2US(t2) - TV2US(t1)) < 100000; /* us */
+    }
+    close(fd);
+    return ret;
+}], [apr_cv_epoll_wait_has_reliable_timeout=yes],
+    [apr_cv_epoll_wait_has_reliable_timeout=no],
+    [apr_cv_epoll_wait_has_reliable_timeout=no])])
+
+if test "$apr_cv_epoll_wait_has_reliable_timeout" = "yes"; then
+   AC_DEFINE([HAVE_EPOLL_WAIT_RELIABLE_TIMEOUT], 1,
+             [Define if epoll_wait has a reliable timeout (min)])
+fi
+
 # Check for z/OS async i/o support.  
 AC_CACHE_CHECK([for asio -> message queue support], [apr_cv_aio_msgq],
 [AC_TRY_RUN([