> On Apr 29, 2024, at 18:29, Guo, Yejun <[email protected]> > wrote: > > > >> -----Original Message----- >> From: ffmpeg-devel <[email protected]> On Behalf Of Zhao >> Zhili >> Sent: Sunday, April 28, 2024 6:55 PM >> To: FFmpeg development discussions and patches <ffmpeg- >> [email protected]> >> Subject: Re: [FFmpeg-devel] [PATCH WIP 0/9] Refactor DNN >> >> >> >>> On Apr 28, 2024, at 18:34, Guo, Yejun <yejun.guo-at- >> [email protected]> wrote: >>> >>>> -----Original Message----- >>>> From: ffmpeg-devel <[email protected] >>>> <mailto:[email protected]>> On Behalf Of Zhao Zhili >>>> Sent: Sunday, April 28, 2024 12:42 AM >>>> To: [email protected] <mailto:[email protected]> >>>> Cc: Zhao Zhili <[email protected] <mailto:[email protected]>> >>>> Subject: [FFmpeg-devel] [PATCH WIP 0/9] Refactor DNN >>>> >>>> From: Zhao Zhili <[email protected]> >>>> >>>> During the refactor progress, I have found some serious issues, which >>>> is not resolved by the patchset: >>>> >>>> 1. Tensorflow backend is broken. >>>> >>>> I think it doesn't work since 2021 at least. For example, it destroy >>>> a thread and create a new thread for each frame, and it destroy an >>>> invalid thread at the first >>>> frame: >>> >>> It works from the day that code is merged, till today. It is by design >>> to keep the code simplicity by using the feature that pthread_join >>> accepts a parameter that is not a joinable thread. >>> >>> Please share more info if you experienced a real case that it does not work. >> >> It will abort if ASSERT_LEVEL > 1. >> >> #define ASSERT_PTHREAD_ABORT(func, ret) do { \ >> char errbuf[AV_ERROR_MAX_STRING_SIZE] = ""; \ >> av_log(NULL, AV_LOG_FATAL, AV_STRINGIFY(func) \ >> " failed with error: %s\n", \ >> av_make_error_string(errbuf, AV_ERROR_MAX_STRING_SIZE, \ >> AVERROR(ret))); \ >> abort(); \ >> } while (0) >> >> I think the check is there just to prevent call pthread_join(0, &ptr) by >> accident, >> so we shouldn’t do that on purpose. >> > Nice catch with configure assert level > 1, will fix, and patch also welcome, > thanks.
If I read the code correctly, it destroy a thread and create a new thread for each frame. I think this “async” mode isn’t common in ffmpeg’s design. Create new thread for each frame can be heavy on some platforms. We use slice threading to improve parallel, and thread with command queue to improve throughput. In this case with tensorflow do the heavy lift, if it doesn’t support async operation, simple synchronous operation with tensorflow backend should be find. The “async” mode is unnecessary and use more resource over the benefit it provides. > _______________________________________________ > ffmpeg-devel mailing list > [email protected] > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > [email protected] with subject "unsubscribe". _______________________________________________ ffmpeg-devel mailing list [email protected] https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email [email protected] with subject "unsubscribe".
