linux-kernel - Re: [patch] CFS scheduler, -v12

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Message-ID: <20070529204557.GB3693@linux-os.sc.intel.com>
Date:	Tue, 29 May 2007 13:45:57 -0700
From:	"Siddha, Suresh B" <suresh.b.siddha@...el.com>
To:	Peter Williams <pwil3058@...pond.net.au>
Cc:	"Siddha, Suresh B" <suresh.b.siddha@...el.com>,
	Ingo Molnar <mingo@...e.hu>, colpatch@...ibm.com,
	Nick Piggin <nickpiggin@...oo.com.au>,
	Con Kolivas <kernel@...ivas.org>,
	Christoph Lameter <clameter@....com>,
	Dmitry Adamushko <dmitry.adamushko@...il.com>,
	Linux Kernel <linux-kernel@...r.kernel.org>
Subject: Re: [patch] CFS scheduler, -v12

On Thu, May 24, 2007 at 04:23:19PM -0700, Peter Williams wrote:
> Siddha, Suresh B wrote:
> > On Thu, May 24, 2007 at 12:43:58AM -0700, Peter Williams wrote:
> > >
> > > Further testing indicates that CONFIG_SCHED_MC is not implicated and
> > > it's CONFIG_SCHED_SMT that's causing the problem.  This rules out the
> > > code in find_busiest_group() as it is common to both macros.
> > >
> > > I think this makes the scheduling domain parameter values the most
> > > likely cause of the problem.  I'm not very familiar with this code so
> > > I've added those who've modified this code in the last year or
> > > so to the
> > > address of this e-mail.
> >
> > What platform is this? I remember you mentioned its a 2 cpu box. Is it
> > dual core or dual package or one with HT?
> 
> It's a single CPU HT box i.e. 2 virtual CPUs.  "cat /proc/cpuinfo"
> produces:

Peter, I tried on a similar box and couldn't reproduce this problem
with x86_64 2.6.22-rc3 kernel and using defconfig(has SCHED_SMT turned on).
I am using top and just the spinners.  I don't have gkrellm running, is that
required to reproduce the issue?

I tried number of times and also in runlevels 3,5(with top running
in a xterm incase of runlevel 5).

In runlevel 5, occasionally for one refresh screen of top, I see three
spinners on one cpu and one spinner on other(with X or someother app
also on the cpu with one spinner). But it balances nicely for the
immd next refresh of the top screen.

I tried with various refresh rates of top too.. Do you see the issue
at runlevel 3 too?

thanks,
suresh
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