On 7/13/2022 12:54 PM, Marco Vianini wrote:
Sorry, my mail client was using html format. I hope now the mail will be sent correctly.You can get a very big improvement of performances in the special (but very likely) case of: "(dst_linesize == bytewidth && src_linesize == bytewidth)" In this case in fact We can "Coalesce rows", that is using ONLY ONE MEMCPY, instead of a smaller memcpy for every row (that is looping for height times). Code: " static void image_copy_plane(uint8_t *dst, ptrdiff_t dst_linesize, const uint8_t *src, ptrdiff_t src_linesize, ptrdiff_t bytewidth, int height) { if (!dst || !src) return; av_assert0(abs(src_linesize) >= bytewidth); av_assert0(abs(dst_linesize) >= bytewidth);/// MY PATCH START/// Coalesce rows. if (dst_linesize == bytewidth && src_linesize == bytewidth) { bytewidth *= height; height = 1; src_linesize = dst_linesize = 0; } /// MY PATCH STOP for (;height > 0; height--) { memcpy(dst, src, bytewidth); dst += dst_linesize; src += src_linesize; } } " I did following tests on Windows 10 64bit. I compiled code in Release. I copied my pc camera frames 1000 times (resolution 1920x1080): With Coalesce: copy_cnt=100 size=1920x1080 tot_time_copy(us)=36574 (average=365.74) copy_cnt=200 size=1920x1080 tot_time_copy(us)=78207 (average=391.035) copy_cnt=300 size=1920x1080 tot_time_copy(us)=122170(average=407.233) copy_cnt=400 size=1920x1080 tot_time_copy(us)=163678(average=409.195) copy_cnt=500 size=1920x1080 tot_time_copy(us)=201872(average=403.744) copy_cnt=600 size=1920x1080 tot_time_copy(us)=246174(average=410.29) copy_cnt=700 size=1920x1080 tot_time_copy(us)=287043(average=410.061) copy_cnt=800 size=1920x1080 tot_time_copy(us)=326462(average=408.077) copy_cnt=900 size=1920x1080 tot_time_copy(us)=356882(average=396.536) copy_cnt=1000 size=1920x1080 tot_time_copy(us)=394566(average=394.566) Without Coalesce: copy_cnt=100 size=1920x1080 tot_time_copy(us)=44303 (average=443.03) copy_cnt=200 size=1920x1080 tot_time_copy(us)=100501(average=502.505) copy_cnt=300 size=1920x1080 tot_time_copy(us)=150097(average=500.323) copy_cnt=400 size=1920x1080 tot_time_copy(us)=201010(average=502.525) copy_cnt=500 size=1920x1080 tot_time_copy(us)=256818(average=513.636) copy_cnt=600 size=1920x1080 tot_time_copy(us)=303273(average=505.455) copy_cnt=700 size=1920x1080 tot_time_copy(us)=359152(average=513.074) copy_cnt=800 size=1920x1080 tot_time_copy(us)=414413(average=518.016) copy_cnt=900 size=1920x1080 tot_time_copy(us)=465315(average=517.017) copy_cnt=1000 size=1920x1080 tot_time_copy(us)=520381(average=520.381) I think the results are very good. What do you think about?
It looks like a good speed up, but we need a patch created with git format-patch that can be applied to the source tree to properly review this. Can you send that?
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