From: Peter Zijlstra <peterz@infradead.org>
To: Paul Turner <pjt@google.com>
Cc: Lei Wen <adrian.wenl@gmail.com>,
LKML <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@kernel.org>, Lei Wen <leiwen@marvell.com>
Subject: Re: false nr_running check in load balance?
Date: Thu, 15 Aug 2013 19:39:53 +0200 [thread overview]
Message-ID: <20130815173953.GU24092@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <CAPM31R+FDXUNb_X9R6O+kqjsAJftEzmyk+Ji=KoAyzEsTDWLew@mail.gmail.com>
On Tue, Aug 13, 2013 at 01:08:17AM -0700, Paul Turner wrote:
> On Tue, Aug 13, 2013 at 12:38 AM, Peter Zijlstra <peterz@infradead.org> wrote:
> > On Tue, Aug 13, 2013 at 12:45:12PM +0800, Lei Wen wrote:
> >> > Not quite right; I think you need busiest->cfs.h_nr_running.
> >> > cfs.nr_running is the number of entries running in this 'group'. If
> >> > you've got nested groups like:
> >> >
> >> > 'root'
> >> > \
> >> > 'A'
> >> > / \
> >> > t1 t2
> >> >
> >> > root.nr_running := 1 'A', even though you've got multiple running tasks.
One thing though; doesn't h_nr_running over count the number of tasks?
That is, doesn't it count the runnable entities so the above case would
give root.h_nr_running := 3, where we would only have 2 runnable tasks.
Double check this and be careful when doing the conversion.
next prev parent reply other threads:[~2013-08-15 17:40 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-06 13:23 false nr_running check in load balance? Lei Wen
2013-08-12 14:43 ` Peter Zijlstra
2013-08-13 4:45 ` Lei Wen
2013-08-13 7:38 ` Peter Zijlstra
2013-08-13 8:08 ` Paul Turner
2013-08-13 8:18 ` Lei Wen
2013-08-13 9:25 ` Paul Turner
2013-08-18 9:12 ` Lei Wen
2013-08-15 17:39 ` Peter Zijlstra [this message]
2013-08-15 18:23 ` Paul Turner
2013-08-15 18:39 ` Peter Zijlstra
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