Date: Wed, 21 Apr 2004 07:40:06 -0400 From: Jeffrey Racine <jracine@maxwell.syr.edu> To: obrien@freebsd.org Cc: freebsd-cluster@freebsd.org Subject: Re: LAM MPI on dual processor opteron box sees only one cpu... Message-ID: <1082547606.31496.3.camel@x1-6-00-b0-d0-c2-67-0e.twcny.rr.com> In-Reply-To: <20040420033208.GB98258@dragon.nuxi.com> References: <024f01c41ffa$029327e0$0c03a8c0@internal.thebeatbox.org> <1081775064.990.13.camel@x1-6-00-b0-d0-c2-67-0e.twcny.rr.com> <20040420033208.GB98258@dragon.nuxi.com>
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Hi David.
Thanks for your response. With the 4BSD scheduler, things run as
expected... lam with 2 processors always fires up cpu 0 and 1 and
distributes the load evenly...
PID USERNAME PRI NICE SIZE RES STATE C TIME WCPU CPU
COMMAND
838 jracine 101 0 5632K 2012K CPU0 0 0:02 58.94% 5.62%
n_lam
839 jracine 101 0 5616K 1968K RUN 1 0:02 57.91% 5.52%
n_lam
-- Jeff
On Mon, 2004-04-19 at 23:32, David O'Brien wrote:
> On Mon, Apr 12, 2004 at 09:04:24AM -0400, Jeffrey Racine wrote:
> > Hi Roland.
> >
> > I do get CPU #1 launched. This is not the problem.
> >
> > The problem appears to be with the way that current is scheduling.
> >
> > With mpirun np 2 I get the job running on CPU 0 (two instances on one
> > proc). However, it turns out that with np 4 I get the job running on CPU
> > 0 and 1 though with 4 instances (and associated overhead). Here is top
> > for np 4... notice that in the C column it is using both procs.
> >
> > PID USERNAME PRI NICE SIZE RES STATE C TIME WCPU CPU
> > COMMAND
> > 96090 jracine 131 0 7148K 2172K CPU1 1 0:19 44.53% 44.53%
> > n_lam
> > 96088 jracine 125 0 7148K 2172K RUN 0 0:18 43.75% 43.75%
> > n_lam
> > 96089 jracine 136 0 7148K 2172K RUN 1 0:19 42.19% 42.19%
> > n_lam
> > 96087 jracine 135 0 7188K 2248K RUN 0 0:19 41.41% 41.41%
> > n_lam
> >
> >
> > One run (once when I rebooted lam) did allocate the job correctly with
> > np 2, but this is not in general the case. On other systems I use,
> > however, they correctly farm out np 2 to CPU 0 and 1...
> >
> > Thanks, and any suggestions welcome.
>
> 1. Please don't top-post -- it looses context. This is a Unix list, not
> Mikeysoft one.
>
> 2. Have you tried with the 4.4BSD scheduler vs. the "ULE" scheduler?
> To test, replace:
> options SCHED_ULE # ULE scheduler
> with
> options SCHED_4BSD #4BSD scheduler
>
> -- David
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