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| author | Ronald S. Bultje <rsbultje@gmail.com> | 2017-04-06 13:58:59 -0400 |
|---|---|---|
| committer | Michael Niedermayer <michael@niedermayer.cc> | 2017-04-13 02:29:26 +0200 |
| commit | 1968a1eef1cae22e162259d7082c2eea98d81e32 (patch) | |
| tree | 0a470f8f550764b0df0044c091a5162f7850b391 | |
| parent | f4f3bf3c94a9aa485c09d0c03d68ca79a4785866 (diff) | |
| download | ffmpeg-n3.3.tar.gz | |
pthread_frame: make accesses to debug field be protected by owner lock.n3.3
The av_log() is done outside the lock, but this way the accesses to the
field (reads and writes) are always protected by a mutex. The av_log()
is not run inside the lock context because it may involve user callbacks
and doing that in performance-sensitive code is probably not a good idea.
This should fix occasional tsan warnings when running fate-h264, like:
WARNING: ThreadSanitizer: data race (pid=10916)
Write of size 4 at 0x7d64000174fc by main thread (mutexes: write M2313):
#0 update_context_from_user src/libavcodec/pthread_frame.c:335 (ffmpeg+0x000000df7b06)
[..]
Previous read of size 4 at 0x7d64000174fc by thread T1 (mutexes: write M2311):
#0 ff_thread_await_progress src/libavcodec/pthread_frame.c:592 (ffmpeg+0x000000df8b3e)
(cherry picked from commit 2e664b9c1e73c80aab91070c1eb7676f04bdd12d)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
| -rw-r--r-- | libavcodec/pthread_frame.c | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/libavcodec/pthread_frame.c b/libavcodec/pthread_frame.c index c246c2fded..0ba87b5929 100644 --- a/libavcodec/pthread_frame.c +++ b/libavcodec/pthread_frame.c @@ -566,12 +566,11 @@ void ff_thread_report_progress(ThreadFrame *f, int n, int field) p = f->owner[field]->internal->thread_ctx; + pthread_mutex_lock(&p->progress_mutex); if (f->owner[field]->debug&FF_DEBUG_THREADS) av_log(f->owner[field], AV_LOG_DEBUG, "%p finished %d field %d\n", progress, n, field); - pthread_mutex_lock(&p->progress_mutex); - atomic_store_explicit(&progress[field], n, memory_order_release); pthread_cond_broadcast(&p->progress_cond); @@ -589,11 +588,10 @@ void ff_thread_await_progress(ThreadFrame *f, int n, int field) p = f->owner[field]->internal->thread_ctx; + pthread_mutex_lock(&p->progress_mutex); if (f->owner[field]->debug&FF_DEBUG_THREADS) av_log(f->owner[field], AV_LOG_DEBUG, "thread awaiting %d field %d from %p\n", n, field, progress); - - pthread_mutex_lock(&p->progress_mutex); while (atomic_load_explicit(&progress[field], memory_order_relaxed) < n) pthread_cond_wait(&p->progress_cond, &p->progress_mutex); pthread_mutex_unlock(&p->progress_mutex); |