ULE vs. 4BSD in RELENG_7
Josh Carroll
josh.carroll at gmail.com
Tue Oct 23 12:57:55 PDT 2007
> ULE is tuned towards providing cpu affinity compilation and evidently
> encoding are workloads that do not benefit from affinity. Before we
> conclude that it is slower, try building with -j5, -j6, j7.
Here are the results of running ffmpeg with 4 through 8 threads on
both schedulers:
4 threads 4bsd: 117.21
5 threads 4bsd: 95.75
6 threads 4bsd: 93.10
7 threads 4bsd: 92.19
8 threads 4bsd: 92.38
4 threads ule: 122.19
5 threads ule: 107.26
6 threads ule: 101.40
7 threads ule: 98.72
8 threads ule: 96.38
4 threads difference: 4.25 %
5 threads difference: 12.02 %
6 threads difference: 8.92 %
7 threads difference: 7.08 %
8 threads difference: 4.33 %
I'm not sure why the performance differential is not consistent
(probably something very technical a scheduler developer could
explain) :)
Do these results help at all? When running with 9 or more threads,
ffmpeg spits out a lot of errors, so 8 was as high as I could go:
Error while decoding stream #0.0
[h264 @ 0x264ae180]too many threads
[h264 @ 0x264ae180]decode_slice_header error
[h264 @ 0x264ae180]no frame!
My next step is to run some transcodes with mencoder to see if it has
similar performance between the two schedulers. When I have those
results, I'll post them to this thread.
Thanks for the attention,
Josh
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