Re: [FFmpeg-devel] [PATCH 3/3] avformat/mpegts: use av_unlikely for detecting unknown streams
2019-01-25 2:03 GMT+01:00, Marton Balint : > > On Fri, 25 Jan 2019, Carl Eugen Hoyos wrote: > >> 2019-01-24 21:38 GMT+01:00, Marton Balint : >>> Strangely the previous commit caused a slowdown in overall performance >>> and this fixes it. I used gcc 7.3.1. Does anybody else see this? >> >> No, but since this command exists nearly immediately for me >> I see a 5% deviation even without your patch. > > Thanks for checking it. I tested my series on top of > 1b126ec4087ab5d87d413116bee666495b0d2d3e, and can still reproduce the > speedup on it. On the other hand, on current git head, I can no longer > reproduce the speedup. Whatever this is, the fact that using av_unlikely > fixed it is probably just luck. > > So considering the mixed feelings about av_(un)likely in general, I'll > just drop patch 1 and 3. I would love to test a command line where it makes a (very) clear difference, I wonder a little about the claim that it would help (measurably) on some systems but not others. Carl Eugen ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
Re: [FFmpeg-devel] [PATCH 3/3] avformat/mpegts: use av_unlikely for detecting unknown streams
On Fri, 25 Jan 2019, Carl Eugen Hoyos wrote: 2019-01-24 21:38 GMT+01:00, Marton Balint : Strangely the previous commit caused a slowdown in overall performance and this fixes it. I used gcc 7.3.1. Does anybody else see this? No, but since this command exists nearly immediately for me I see a 5% deviation even without your patch. Thanks for checking it. I tested my series on top of 1b126ec4087ab5d87d413116bee666495b0d2d3e, and can still reproduce the speedup on it. On the other hand, on current git head, I can no longer reproduce the speedup. Whatever this is, the fact that using av_unlikely fixed it is probably just luck. So considering the mixed feelings about av_(un)likely in general, I'll just drop patch 1 and 3. Thanks, Marton ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
Re: [FFmpeg-devel] [PATCH 3/3] avformat/mpegts: use av_unlikely for detecting unknown streams
2019-01-24 21:38 GMT+01:00, Marton Balint : > Strangely the previous commit caused a slowdown in overall performance > and this fixes it. I used gcc 7.3.1. Does anybody else see this? No, but since this command exists nearly immediately for me I see a 5% deviation even without your patch. Carl Eugen ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
[FFmpeg-devel] [PATCH 3/3] avformat/mpegts: use av_unlikely for detecting unknown streams
Strangely the previous commit caused a slowdown in overall performance and
this fixes it. I used gcc 7.3.1. Does anybody else see this?
time ffprobe -show_packets
samples/ffmpeg-bugs/trac/ticket6132/Samsung_HDR_-_Chasing_the_Light.ts >
/dev/null
Before:
real0m2,010s
user0m1,413s
sys 0m0,596s
After:
real0m1,948s
user0m1,355s
sys 0m0,592s
Signed-off-by: Marton Balint
---
libavformat/mpegts.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/libavformat/mpegts.c b/libavformat/mpegts.c
index b04fd7b4f4..3003739b38 100644
--- a/libavformat/mpegts.c
+++ b/libavformat/mpegts.c
@@ -2477,7 +2477,7 @@ static int handle_packet(MpegTSContext *ts, const uint8_t
*packet)
pid = AV_RB16(packet + 1) & 0x1fff;
is_start = packet[1] & 0x40;
tss = ts->pids[pid];
-if (ts->auto_guess && !tss && is_start) {
+if (av_unlikely(ts->auto_guess && !tss && is_start)) {
add_pes_stream(ts, pid, -1);
tss = ts->pids[pid];
}
--
2.16.4
___
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
