SCHED_4BSD in RELENG_7 disturbs workflow

Jeff Roberson jroberson at chesapeake.net
Tue Oct 16 13:43:35 PDT 2007


On Tue, 16 Oct 2007, Josh Carroll wrote:

>> Not to say that any problems that might have developed with SCHED_4BSD
>> should not be fixed, but you should give SCHED_ULE a try since it brings
>> benefits even for single CPU systems (e.g. better interactive response).
>
> For my particular work load, 4BSD is actually faster than ULE in
> RELENG_7. Specifically, on a Q6600 running ffmpeg -threads 8 to
> transcode some H.264 video, 4BSD is about 5% faster. I took a sample
> video and transcoded the first 120 seconds of it, and here are the
> results (including a control from 6.2-RELEASE-p7/4BSD scheduler):
>
> releng_6_2 (4BSD)   1:32.39
> releng_7 (4BSD)       1:32.44
> releng_7 (ULE)         1:37.15
>
> This is obviously a different scenario from MySQL. So perhaps ULE
> isn't as well tuned for cases like ffmpeg?

Hi Josh, thanks for the report.  How many CPUs are in your system?  Can 
you give me the output of 'vmstat 5' over the course of one run on 4BSD 
and ULE?  Or just one of them if you can't spare the time.

Thanks,
Jeff

>
> Josh
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