SCHED_ULE should not be the default

O. Hartmann ohartman at mail.zedat.fu-berlin.de
Tue Dec 13 11:13:44 UTC 2011


On 12/12/11 16:13, Vincent Hoffman wrote:
> 
> 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
> 
> 

Interesting, there seems to be a much more performant scheduler in 7.0,
called SCHED_SMP. I have some faint recalls on that ... where is this
beast gone?

Oliver

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