From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Ken Chen <kenchen@google.com>
Cc: Ingo Molnar <mingo@elte.hu>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [patch] sched: fix uneven per-cpu task_group share distribution
Date: Wed, 17 Dec 2008 09:34:11 +0100 [thread overview]
Message-ID: <1229502851.9487.43.camel@twins> (raw)
In-Reply-To: <b040c32a0812170020x1dae7e11taec8e2f4ff9f06f1@mail.gmail.com>
On Wed, 2008-12-17 at 00:20 -0800, Ken Chen wrote:
> On Mon, Dec 15, 2008 at 11:37 PM, Ken Chen <kenchen@google.com> wrote:
> > While testing CFS scheduler on linux-2.6-tip tree
> > git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
> >
> > We found that task which is pinned to a CPU could be starved relative to its
> > allocated fair share.
>
> I just want to poke you two to see if you have time to look over this
> patch. There is a real bug in linux-2.6-tip tree.
>
> If I create a CFS cgroup under directory .../parent/cgdir, put one
> task under 'parent' with CFS weight 1024, and one task under 'cgdir'
> (cgdir has group weight of 1024 also), pin both tasks onto same CPU.
> The CPU cycle allocation on these two tasks will be N:1 where N is
> number of CPUs in the system. The expected allocation should be 1:1.
right - it was on the todo list, let me stare at it a little..
next prev parent reply other threads:[~2008-12-17 8:34 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-12-16 7:37 [patch] sched: fix uneven per-cpu task_group share distribution Ken Chen
2008-12-17 8:20 ` Ken Chen
2008-12-17 8:34 ` Peter Zijlstra [this message]
2008-12-17 8:38 ` Peter Zijlstra
2008-12-18 13:42 ` Ingo Molnar
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