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Date:      Mon, 12 Dec 2011 18:28:41 +0200
From:      Ivan Klymenko <fidaj@ukr.net>
To:        Bruce Cran <bruce@cran.org.uk>
Cc:        "O. Hartmann" <ohartman@mail.zedat.fu-berlin.de>, Current FreeBSD <freebsd-current@freebsd.org>, freebsd-stable@freebsd.org, freebsd-performance@freebsd.org, Steve Kargl <sgk@troutmask.apl.washington.edu>
Subject:   Re: SCHED_ULE should not be the default
Message-ID:  <20111212182841.31f669ca@nonamehost.>
In-Reply-To: <4EE6295B.3020308@cran.org.uk>
References:  <4EE1EAFE.3070408@m5p.com> <4EE22421.9060707@gmail.com> <4EE6060D.5060201@mail.zedat.fu-berlin.de> <20111212155159.GB73597@troutmask.apl.washington.edu> <4EE6295B.3020308@cran.org.uk>

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=D0=92 Mon, 12 Dec 2011 16:18:35 +0000
Bruce Cran <bruce@cran.org.uk> =D0=BF=D0=B8=D1=88=D0=B5=D1=82:

> On 12/12/2011 15:51, Steve Kargl wrote:
> > This comes up every 9 months or so, and must be approaching FAQ=20
> > status. In a HPC environment, I recommend 4BSD. Depending on the=20
> > workload, ULE can cause a severe increase in turn around time when=20
> > doing already long computations. If you have an MPI application,=20
> > simply launching greater than ncpu+1 jobs can show the problem. PS:=20
> > search the list archives for "kargl and ULE".=20
>=20
> This isn't something that can be fixed by tuning ULE? For example for=20
> desktop applications kern.sched.preempt_thresh should be set to 224
> from its default. I'm wondering if the installer should ask people
> what the typical use will be, and tune the scheduler appropriately.
>=20

This is by and large does not help in certain situations ...



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