util: Add non quiesce xnanosleep.

xnanosleep forces the thread into quiesce state in anticipation that
it will be sleeping for a considerable time and that the thread may
need to quiesce before the sleep is finished.

In some cases, a very short sleep may be requested and in that case
the overhead of going to into quiesce state may be unnecessary.

To allow for those cases add a xnanosleep_no_quiesce() variant.

Suggested-by: Ilya Maximets <i.maximets@ovn.org>
Reviewed-by: David Marchand <david.marchand@redhat.com>
Signed-off-by: Kevin Traynor <ktraynor@redhat.com>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>

2 files changed, 18 insertions, 4 deletions

diff --git a/lib/util.c b/lib/util.c
index 1195c7982..7576eb06e 100644
--- a/lib/util.c
+++ b/lib/util.c
@@ -2371,11 +2371,9 @@ xsleep(unsigned int seconds)
     ovsrcu_quiesce_end();
 }
 
-/* High resolution sleep. */
-void
-xnanosleep(uint64_t nanoseconds)
+static void
+xnanosleep__(uint64_t nanoseconds)
 {
-    ovsrcu_quiesce_start();
 #ifndef _WIN32
     int retval;
     struct timespec ts_sleep;
@@ -2403,9 +2401,24 @@ xnanosleep(uint64_t nanoseconds)
                        ovs_lasterror_to_string());
     }
 #endif
+}
+
+/* High resolution sleep with thread quiesce. */
+void
+xnanosleep(uint64_t nanoseconds)
+{
+    ovsrcu_quiesce_start();
+    xnanosleep__(nanoseconds);
     ovsrcu_quiesce_end();
 }
 
+/* High resolution sleep without thread quiesce. */
+void
+xnanosleep_no_quiesce(uint64_t nanoseconds)
+{
+    xnanosleep__(nanoseconds);
+}
+
 /* Determine whether standard output is a tty or not. This is useful to decide
  * whether to use color output or not when --color option for utilities is set
  * to `auto`.
diff --git a/lib/util.h b/lib/util.h
index 9ff84b3dc..f35f33021 100644
--- a/lib/util.h
+++ b/lib/util.h
@@ -593,6 +593,7 @@ ovs_u128_is_superset(ovs_u128 super, ovs_u128 sub)
 
 void xsleep(unsigned int seconds);
 void xnanosleep(uint64_t nanoseconds);
+void xnanosleep_no_quiesce(uint64_t nanoseconds);
 
 bool is_stdout_a_tty(void);