On Sat, 2021-04-10 at 13:32 +0800, Linjie Fu wrote: > Hi Haihao, > > On Thu, Apr 8, 2021 at 3:10 PM Haihao Xiang <haihao.xi...@intel.com> wrote: > > > > By default the SDK creates a thread for each CPU when creating a mfx > > session for decoding / encoding, which results in CPU overhead on a > > multi CPU system. Actually creating 2 threads is a better choice for > > most cases in practice. > > > > This patch allows user to specify the number of threads created for a > > mfx session via option -threads. If the number is not specified, 2 > > threads will be created by default. > > > > Note the SDK requires at least 2 threads to avoid dead locks[1] > > > > [1] > > https://github.com/Intel-Media-SDK/MediaSDK/blob/master/_studio/mfx_lib/scheduler/linux/src/mfx_scheduler_core_ischeduler.cpp#L90-L93 > > --- > > Optional choice for users to specify the thread number looks reasonable to me, > and decreasing the CPU overhead makes sense for HW encoding pipeline. > > Also curious about what's the tradeoff of decreasing the thread number to 2. > Would the performance or something else drop?
Thanks for the comment. MSDK threads are used to execute MSDK tasks. For hw decoding /encoding pipeline, these tasks are very light, so we may use a few threads for msdk tasks. I didn't see performance drop in my testing after applying this patch. Regards Haihao > > - linjie _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
