Gesendet: Dienstag, 06. September 2022 um 23:11 Uhr Von: "Andreas Rheinhardt" <andreas.rheinha...@outlook.com> An: ffmpeg-devel@ffmpeg.org Betreff: Re: [FFmpeg-devel] [PATCH] slicethread: Limit the automatic number of threads to 16 Lukas Fellechner: >> 1. Running out of address space in 32-bit processes >> >> It probably makes sense to limit auto threads to 16, but it should only >> be done in 32-bit processes. A 64-bit process should never run out of >> address space. We should not cripple high end machines running >> 64-bit applications. >> >> >> Sidenotes about "it does not make sense to have more than 16 slices": >> >> On 8K video, when using 32 threads, each thread will process 256 lines >> or about 1MP (> FullHD!). Sure makes sense to me. But even for sw decoding >> 4K video, having more than 16 threads on a powerful machine makes sense. >> >> Intel's next desktop CPUs will have up to 24 physical cores. The >> proposed change would limit them to use only 16 cores, even on 64-bit. > > This part is completely wrong: You can always set the number of threads > manually. > (Btw: 1. 8K is the horizontal resolution; the vertical resolution of it > is 4360 (when using 16:9), so every thread processes 135 lines which > have as many pixels as 540 lines of FullHD. 2. FullHD has about 2MP.) > > - Andreas
You are right. What I ment was: When someone does not explicitly set threads, then only 16 of his 24 cores will be used. I know that it is always possible to manually override the auto value without limits. And indeed I somehow confused the resolutions. Sill each thread would process 1MP of pixel data, which is a lot of data. - Lukas _______________________________________________ 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".
