On Mon, 30 Mar 2020, 15:31 Dennis Mungai, <[email protected]> wrote: > On Mon, 30 Mar 2020, 15:22 Valentin Schweitzer, <[email protected]> > wrote: > >> 1234567890123456789012345678901234567890123456789012345678901234567890 >> >> Hi, >> >> when using scale_npp to scale a test video down from 1920x1080 to >> 1024x576 or lower with multiple processes in parallel, CPU usage is >> unusually high.For context, when scaling the same video down to >> 1280x720, CPU usage stays at about0.5% per FFmpeg instance. When >> scaling down too 1024x576 or lower, CPU usage per FFmpeg process rises >> to about 3.0%. The values listed here appear when starting 29 >> instances of FFmpeg in parallel. The effect is less pronounced but >> still visible at 10 instances in parallel. Hardware used for this >> is an AMD EPYC 7401P 24 Core + NVIDIA Quadro RTX 4000. >> >> To generate 100s of random noise in 1080p (which will be the test video): >> >> ffmpeg -y -hide_banner -f lavfi -i nullsrc=s=1920x1080 -filter_complex >> "geq=random(1)*255:128:128;aevalsrc=-2+random(0)" -vcodec rawvideo >> -acodec pcm_s16le -t 100 noise.mkv >> >> Now rescale the test video to 720p: >> >> ffmpeg -hide_banner -y -i noise.mkv -vf >> hwupload_cuda,scale_npp=w=1280:h=720:format=nv12 -vcodec h264_nvenc -an >> -f null NUL >> >> This should not cause very high CPU usage. Now rescale the same video to >> 576p: >> >> ffmpeg -hide_banner -y -i noise.mkv -vf >> hwupload_cuda,scale_npp=w=1024:h=576:format=nv12 -vcodec h264_nvenc -an >> -f null NUL >> >> This should cause about 5 or 6 times as much CPU usage. >> >> This might be caused by some NVIDIA optimizations, but it does not >> seem to be documented and I have yet to find a good place to ask >> > > > Set this environment variable: CUDA_DEVICE_MAX_CONNECTIONS=2 > > Then retest and report back. >
One more thing: Could you show us the output of: numactl --hardware _______________________________________________ ffmpeg-user mailing list [email protected] https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email [email protected] with subject "unsubscribe".
