From: Peter Zijlstra <peterz@infradead.org>
To: Mitchell Erblich <erblichs@earthlink.net>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>
Subject: Re: CFS Scheduler : Period : for NCPUs : Code Suggestion Change
Date: Mon, 06 Jul 2009 14:46:20 +0200 [thread overview]
Message-ID: <1246884380.8143.12.camel@twins> (raw)
In-Reply-To: <B99DC9EB-9502-4E31-B829-6EB7EFC6212C@earthlink.net>
On Tue, 2009-06-30 at 18:36 -0700, Mitchell Erblich wrote:
> This is NOT A PATCH.
>
> PLEASE include my email in the reply as I am not currently on
> the linux kernel mail alias.
>
> This code snap is grabbed from what is believed to be a semi-current
> OS source (fxr.watson.org) comparison webpage.
>
> Upon a quick CFS scheduler code walk, increasing the period
> should ALSO be dependent on the number of online/active CPUs.
>
> The period should be adjusted based on the number of
> online CPUs. This change allows NCPUs * tasks without
> changing/increasing the period.
>
> On first thought NR_CPUS should give the number of cpu on
> the system, however, this may be different from the number of
> CPUs online, thus..
>
> Change #1: place after line 425
> int cpu, ncpu;
>
>
> Change #2: place before line 427
> for_each_online_cpu(cpu) {
> ncpu++;
> }
> nr_running /= ncpu;
>
Ah, but the nr_running number used is _per_ cpu already, so would that
address your concern?
prev parent reply other threads:[~2009-07-06 12:46 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-07-01 1:36 CFS Scheduler : Period : for NCPUs : Code Suggestion Change Mitchell Erblich
2009-07-06 12:46 ` Peter Zijlstra [this message]
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