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Date: Tue, 13 Dec 2011 13:00:51 +0400
From: Andrey Chernov <ache@FreeBSD.ORG>
To: Ivan Klymenko <fidaj@ukr.net>
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	Ivan Klymenko <fidaj@ukr.net>, Doug Barton <dougb@FreeBSD.ORG>,
	"O. Hartmann" <ohartman@mail.zedat.fu-berlin.de>,
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Cc: freebsd-stable@FreeBSD.ORG,
	"O. Hartmann" <ohartman@mail.zedat.fu-berlin.de>,
	Doug Barton <dougb@FreeBSD.ORG>,
	Current FreeBSD <freebsd-current@FreeBSD.ORG>,
	freebsd-performance@FreeBSD.ORG
Subject: Re: SCHED_ULE should not be the default
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On Tue, Dec 13, 2011 at 10:40:48AM +0200, Ivan Klymenko wrote:
> > On 12/12/2011 05:47, O. Hartmann wrote:
> > > Do we have any proof at hand for such cases where SCHED_ULE performs
> > > much better than SCHED_4BSD?
> > 
> > I complained about poor interactive performance of ULE in a desktop
> > environment for years. I had numerous people try to help, including
> > Jeff, with various tunables, dtrace'ing, etc. The cause of the problem
> > was never found.
> > 
> > I switched to 4BSD, problem gone.
> > 
> > This is on 2 separate systems with core 2 duos.
> > 
> > 
> > hth,
> > 
> > Doug
> > 
> 
> If the algorithm ULE does not contain problems - it means the problem
> has Core2Duo, or in a piece of code that uses the ULE scheduler.

I observe ULE interactivity slowness even on single core machine (Pentium 
4) in very visible places, like 'ps ax' output stucks in the middle by ~1 
second. When I switch back to SHED_4BSD, all slowness is gone.

-- 
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