Re: SCHED_ULE should not be the default

From: Vincent Hoffman <vince_at_unsane.co.uk>
Date: Mon, 12 Dec 2011 15:13:00 +0000
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On 12/12/2011 13:47, O. Hartmann wrote:
>
>> Not fully right, boinc defaults to run on idprio 31 so this isn't an
>> issue. And yes, there are cases where SCHED_ULE shows much better
>> performance then SCHED_4BSD. [...]
>
> Do we have any proof at hand for such cases where SCHED_ULE performs
> much better than SCHED_4BSD? Whenever the subject comes up, it is
> mentioned, that SCHED_ULE has better performance on boxes with a ncpu >
> 2. But in the end I see here contradictionary statements. People
> complain about poor performance (especially in scientific environments),
> and other give contra not being the case.
It all a little old now but some if the stuff in
http://people.freebsd.org/~kris/scaling/
covers improvements that were seen.

http://jeffr-tech.livejournal.com/5705.html
shows a little too, reading though Jeffs blog is worth it as it has some
interesting stuff on SHED_ULE.

I thought there were some more benchmarks floating round but cant find
any with a quick google.


Vince

>
> Within our department, we developed a highly scalable code for planetary
> science purposes on imagery. It utilizes present GPUs via OpenCL if
> present. Otherwise it grabs as many cores as it can.
> By the end of this year I'll get a new desktop box based on Intels new
> Sandy Bridge-E architecture with plenty of memory. If the colleague who
> developed the code is willing performing some benchmarks on the same
> hardware platform, we'll benchmark bot FreeBSD 9.0/10.0 and the most
> recent Suse. For FreeBSD I intent also to look for performance with both
> different schedulers available.
>
> O.
>

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Received on Mon Dec 12 2011 - 14:13:03 UTC

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