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authorWan-Teh Chang <wtc@google.com>2016-12-09 09:54:47 -0800
committerwm4 <nfxjfg@googlemail.com>2017-03-21 06:16:49 +0100
commitc358c62550e60a150c49f192d72631142a6eedd6 (patch)
treef9eb832bd02abce960358900c97d8b3fd1440e88 /libavcodec/vaapi_mpeg2.c
parentfb69a8e1f124ee89e924344bfb7934937abed642 (diff)
pthread_frame: use better memory orders for frame progress
This improves commit 59c70227405c214b29971e6272f3a3ff6fcce3d0. In ff_thread_report_progress(), the fast code path can load progress[field] with the relaxed memory order, and the slow code path can store progress[field] with the release memory order. These changes are mainly intended to avoid confusion when one inspects the source code. They are unlikely to have measurable performance improvement. ff_thread_report_progress() and ff_thread_await_progress() form a pair. ff_thread_await_progress() reads progress[field] with the acquire memory order (in the fast code path). Therefore, one expects to see ff_thread_report_progress() write progress[field] with the matching release memory order. In the fast code path in ff_thread_report_progress(), the atomic load of progress[field] doesn't need the acquire memory order because the calling thread is trying to make the data it just decoded visible to the other threads, rather than trying to read the data decoded by other threads. In ff_thread_get_buffer(), initialize progress[0] and progress[1] using atomic_init(). Signed-off-by: Wan-Teh Chang <wtc@google.com> Signed-off-by: Anton Khirnov <anton@khirnov.net> Merges Libav commit 343e2833. Signed-off-by: wm4 <nfxjfg@googlemail.com>
Diffstat (limited to 'libavcodec/vaapi_mpeg2.c')
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