Date: Wed, 6 Jul 2011 12:36:36 -0700 From: Steve Kargl <sgk@troutmask.apl.washington.edu> To: Arnaud Lacombe <lacombar@gmail.com> Cc: FreeBSD Current <freebsd-current@freebsd.org>, "O. Hartmann" <ohartman@zedat.fu-berlin.de>, arrowdodger <6yearold@gmail.com>, freebsd-questions@freebsd.org Subject: Re: Heavy I/O blocks FreeBSD box for several seconds Message-ID: <20110706193636.GA69550@troutmask.apl.washington.edu> In-Reply-To: <CACqU3MVLr5VXRovs1uV%2BzHazJi2rrjE9Sp3XzsCPJ0Un06pmDQ@mail.gmail.com> References: <4E1421D9.7080808@zedat.fu-berlin.de> <CALH631=F4bSgNDE4w0qcXGMgGxZRRwCP9n-H4M0c%2B1UEaqWr7Q@mail.gmail.com> <4E147F54.40908@zedat.fu-berlin.de> <20110706162811.GA68436@troutmask.apl.washington.edu> <CACqU3MVLr5VXRovs1uV%2BzHazJi2rrjE9Sp3XzsCPJ0Un06pmDQ@mail.gmail.com>
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On Wed, Jul 06, 2011 at 03:18:35PM -0400, Arnaud Lacombe wrote: > Hi, > > On Wed, Jul 6, 2011 at 12:28 PM, Steve Kargl > <sgk@troutmask.apl.washington.edu> wrote: > > On Wed, Jul 06, 2011 at 05:29:24PM +0200, O. Hartmann wrote: > >> > >> I use SCHED_ULE on all machines, since it is supposed to be performing > >> better on multicore boxes, but there are lots of suggestions switching > >> back to the old SCHED_4BSD scheduler. > >> > > > > If you are using MPI in numerical codes, then you want > > to use SCHED_4BSD. ?I've posted numerous times about ULE > > and its very poor performance when using MPI. > > > > http://lists.freebsd.org/pipermail/freebsd-hackers/2008-October/026375.html > > > [sarcasm] > It is rather funny to see that the post you point out has generated > exactly 0 meaningful follow-up then and as you mention later in this > thread, the issue still remains today :-) > [/sarcasm] > Apparently, you are privy to my private email exchanges with jeffr. I'm also not sure why you're being sarcastic here. The issue was and AFAIK still is a problem for anyone using FreeBSD in a HPC cluster. ULE simply performs worse than 4BSD. -- Steve
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