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* [gcc r12-850] openmp: Notify team barrier of pending tasks in omp_fulfill_event
@ 2021-05-17 20:21 Kwok Yeung
0 siblings, 0 replies; only message in thread
From: Kwok Yeung @ 2021-05-17 20:21 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:ba886d0c488ebea2eb2df95c2069a3e207704dac
commit r12-850-gba886d0c488ebea2eb2df95c2069a3e207704dac
Author: Kwok Cheung Yeung <kcy@codesourcery.com>
Date: Fri May 14 09:59:11 2021 -0700
openmp: Notify team barrier of pending tasks in omp_fulfill_event
The team barrier should be notified of any new tasks that become runnable
as the result of a completing task, otherwise the barrier threads might
not resume processing available tasks, resulting in a hang.
2021-05-17 Kwok Cheung Yeung <kcy@codesourcery.com>
libgomp/
* task.c (omp_fulfill_event): Call gomp_team_barrier_set_task_pending
if new tasks generated.
* testsuite/libgomp.c-c++-common/task-detach-13.c: New.
Diff:
---
libgomp/task.c | 1 +
.../libgomp.c-c++-common/task-detach-13.c | 59 ++++++++++++++++++++++
2 files changed, 60 insertions(+)
diff --git a/libgomp/task.c b/libgomp/task.c
index 1c73c759a8d..feb4796a3ac 100644
--- a/libgomp/task.c
+++ b/libgomp/task.c
@@ -2460,6 +2460,7 @@ omp_fulfill_event (omp_event_handle_t event)
if (new_tasks > 0)
{
/* Wake up threads to run new tasks. */
+ gomp_team_barrier_set_task_pending (&team->barrier);
do_wake = team->nthreads - team->task_running_count;
if (do_wake > new_tasks)
do_wake = new_tasks;
diff --git a/libgomp/testsuite/libgomp.c-c++-common/task-detach-13.c b/libgomp/testsuite/libgomp.c-c++-common/task-detach-13.c
new file mode 100644
index 00000000000..9622fd8251f
--- /dev/null
+++ b/libgomp/testsuite/libgomp.c-c++-common/task-detach-13.c
@@ -0,0 +1,59 @@
+/* { dg-do run { target *-*-linux* *-*-gnu* *-*-freebsd* } } */
+/* { dg-timeout 10 } */
+
+/* Test that omp_fulfill_event works when called from an external
+ non-OpenMP thread. */
+
+#include <omp.h>
+#include <unistd.h>
+#include <pthread.h>
+#include <stdio.h>
+
+int finished = 0;
+int event_pending = 0;
+omp_event_handle_t detach_event;
+
+void *
+fulfill_thread (void *)
+{
+ while (!__atomic_load_n (&finished, __ATOMIC_RELAXED))
+ {
+ if (__atomic_load_n (&event_pending, __ATOMIC_ACQUIRE))
+ {
+ omp_fulfill_event (detach_event);
+ __atomic_store_n (&event_pending, 0, __ATOMIC_RELEASE);
+ }
+
+ sleep(1);
+ }
+
+ return 0;
+}
+
+int
+main (void)
+{
+ pthread_t thr;
+ int dep;
+ pthread_create (&thr, NULL, fulfill_thread, 0);
+
+ #pragma omp parallel
+ #pragma omp single
+ {
+ omp_event_handle_t ev;
+
+ #pragma omp task depend (out: dep) detach (ev)
+ {
+ detach_event = ev;
+ __atomic_store_n (&event_pending, 1, __ATOMIC_RELEASE);
+ }
+
+ #pragma omp task depend (in: dep)
+ {
+ __atomic_store_n (&finished, 1, __ATOMIC_RELAXED);
+ }
+ }
+
+ pthread_join (thr, 0);
+ return 0;
+}
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