From e132ccd0ddfabb82641459b36910e79b14f6df88 Mon Sep 17 00:00:00 2001
From: Joseph Schuchart <joseph.schuchart@stonybrook.edu>
Date: Wed, 10 Jul 2024 18:34:22 -0400
Subject: [PATCH] Enable nanosleep with _POSIX_C_SOURCE

Move calls to nanosleep out of headers and add the feature test macro
_POSIX_C_SOURCE to enable its use. This should not cause
any significant overheads.

Signed-off-by: Joseph Schuchart <joseph.schuchart@stonybrook.edu>
---
 opal/class/opal_fifo.h                          |  2 +-
 opal/class/opal_lifo.c                          | 17 +++++++++++++++++
 opal/class/opal_lifo.h                          | 15 ++-------------
 .../threads/pthreads/threads_pthreads_yield.c   |  3 +++
 4 files changed, 23 insertions(+), 14 deletions(-)

diff --git a/opal/class/opal_fifo.h b/opal/class/opal_fifo.h
index 3f04f18ea71..816b2fb0ecd 100644
--- a/opal/class/opal_fifo.h
+++ b/opal/class/opal_fifo.h
@@ -224,7 +224,7 @@ static inline opal_list_item_t *opal_fifo_pop_atomic(opal_fifo_t *fifo)
         if (++attempt == 5) {
             /* deliberately suspend this thread to allow other threads to run. this should
              * only occur during periods of contention on the lifo. */
-            _opal_lifo_release_cpu();
+            opal_lifo_release_cpu();
             attempt = 0;
         }
 
diff --git a/opal/class/opal_lifo.c b/opal/class/opal_lifo.c
index e4bcce794d8..0af332e3e3a 100644
--- a/opal/class/opal_lifo.c
+++ b/opal/class/opal_lifo.c
@@ -19,7 +19,11 @@
  * $HEADER$
  */
 
+/* needed for nanosleep() */
+#define _POSIX_C_SOURCE 200809L
+
 #include "opal_config.h"
+#include <time.h>
 #include "opal/class/opal_lifo.h"
 
 static void opal_lifo_construct(opal_lifo_t *lifo)
@@ -31,3 +35,16 @@ static void opal_lifo_construct(opal_lifo_t *lifo)
 }
 
 OBJ_CLASS_INSTANCE(opal_lifo_t, opal_object_t, opal_lifo_construct, NULL);
+
+
+void opal_lifo_release_cpu(void)
+{
+    /* NTH: there are many ways to cause the current thread to be suspended. This one
+     * should work well in most cases. Another approach would be to use poll (NULL, 0, ) but
+     * the interval will be forced to be in ms (instead of ns or us). Note that there
+     * is a performance improvement for the lifo test when this call is made on detection
+     * of contention but it may not translate into actually MPI or application performance
+     * improvements. */
+    static struct timespec interval = {.tv_sec = 0, .tv_nsec = 100};
+    nanosleep(&interval, NULL);
+}
diff --git a/opal/class/opal_lifo.h b/opal/class/opal_lifo.h
index d659ca2a9c7..72cc531e3b8 100644
--- a/opal/class/opal_lifo.h
+++ b/opal/class/opal_lifo.h
@@ -30,7 +30,6 @@
 
 #include "opal_config.h"
 #include "opal/class/opal_list.h"
-#include <time.h>
 
 #include "opal/mca/threads/mutex.h"
 #include "opal/sys/atomic.h"
@@ -92,17 +91,7 @@ opal_read_counted_pointer(volatile opal_counted_pointer_t *volatile addr,
 /**
  * @brief Helper function for lifo/fifo to sleep this thread if excessive contention is detected
  */
-static inline void _opal_lifo_release_cpu(void)
-{
-    /* NTH: there are many ways to cause the current thread to be suspended. This one
-     * should work well in most cases. Another approach would be to use poll (NULL, 0, ) but
-     * the interval will be forced to be in ms (instead of ns or us). Note that there
-     * is a performance improvement for the lifo test when this call is made on detection
-     * of contention but it may not translate into actually MPI or application performance
-     * improvements. */
-    static struct timespec interval = {.tv_sec = 0, .tv_nsec = 100};
-    nanosleep(&interval, NULL);
-}
+void opal_lifo_release_cpu(void);
 
 /* Atomic Last In First Out lists. If we are in a multi-threaded environment then the
  * atomicity is insured via the compare-and-swap operation, if not we simply do a read
@@ -225,7 +214,7 @@ static inline opal_list_item_t *opal_lifo_pop_atomic(opal_lifo_t *lifo)
         if (++attempt == 5) {
             /* deliberately suspend this thread to allow other threads to run. this should
              * only occur during periods of contention on the lifo. */
-            _opal_lifo_release_cpu();
+            opal_lifo_release_cpu();
             attempt = 0;
         }
 
diff --git a/opal/mca/threads/pthreads/threads_pthreads_yield.c b/opal/mca/threads/pthreads/threads_pthreads_yield.c
index 3ae102e43e0..4ab5caa85ec 100644
--- a/opal/mca/threads/pthreads/threads_pthreads_yield.c
+++ b/opal/mca/threads/pthreads/threads_pthreads_yield.c
@@ -10,6 +10,9 @@
  * $HEADER$
  */
 
+/* needed for nanosleep() */
+#define _POSIX_C_SOURCE 200809L
+
 #include "opal_config.h"
 #include <time.h>
 #ifdef HAVE_SCHED_H