From: Ingo Molnar <mingo@elte.hu>
To: Micah Dowty <micah@vmware.com>
Cc: Christoph Lameter <clameter@sgi.com>,
Kyle Moffett <mrmacman_g4@mac.com>,
Cyrus Massoumi <cyrusm@gmx.net>,
LKML Kernel <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@osdl.org>, Mike Galbraith <efault@gmx.de>,
Paul Menage <menage@google.com>,
Dmitry Adamushko <dmitry.adamushko@gmail.com>,
Peter Williams <pwil3058@bigpond.net.au>
Subject: Re: High priority tasks break SMP balancer?
Date: Fri, 16 Nov 2007 07:07:00 +0100 [thread overview]
Message-ID: <20071116060700.GD16273@elte.hu> (raw)
In-Reply-To: <20071116024408.GA20322@vmware.com>
* Micah Dowty <micah@vmware.com> wrote:
> > I am a bit at a loss as to how this could relate to the patch. This
> > looks like a load balance logic issue that causes the load
> > calculation to go wrong?
>
> My best guess is that this has something to do with the timing with
> which we sample the CPU's instantaneous load when calculating the load
> averages.. but I still understand only the basics of the scheduler and
> SMP balancer. All I really know for sure at this point regarding your
> patch is that git-bisect found it for me.
hm, your code uses timeouts for this, right? The CPU load average that
is used for SMP load balancing is sampled from the scheduler tick - and
has been sampled from the scheduler tick for eons. v2.6.23 defaulted to
a different method but v2.6.24 samples it from the tick again. So my
guess is, your testcode behave similarly on 2.6.22 too, correct?
Ingo
next prev parent reply other threads:[~2007-11-16 6:07 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-11-09 22:34 High priority tasks break SMP balancer? Micah Dowty
2007-11-09 23:56 ` Cyrus Massoumi
2007-11-10 0:11 ` Micah Dowty
2007-11-14 18:39 ` Micah Dowty
2007-11-15 18:48 ` Kyle Moffett
2007-11-15 19:14 ` Micah Dowty
2007-11-15 20:07 ` Christoph Lameter
2007-11-15 20:24 ` Micah Dowty
2007-11-15 21:28 ` Christoph Lameter
2007-11-15 21:35 ` Micah Dowty
2007-11-16 2:31 ` Christoph Lameter
2007-11-16 2:44 ` Micah Dowty
2007-11-16 6:07 ` Ingo Molnar [this message]
2007-11-16 9:19 ` Micah Dowty
2007-11-16 10:45 ` Ingo Molnar
2007-11-16 10:48 ` Micah Dowty
2007-11-16 22:12 ` Christoph Lameter
2007-11-16 10:48 ` Dmitry Adamushko
2007-11-16 22:14 ` Micah Dowty
2007-11-16 23:26 ` Dmitry Adamushko
2007-11-17 1:03 ` Micah Dowty
2007-11-17 19:10 ` Dmitry Adamushko
2007-11-19 18:51 ` Micah Dowty
2007-11-19 22:22 ` Dmitry Adamushko
2007-11-19 23:05 ` Micah Dowty
2007-11-20 5:57 ` Ingo Molnar
2007-11-20 18:06 ` Micah Dowty
2007-11-20 21:47 ` Dmitry Adamushko
2007-11-22 7:46 ` Micah Dowty
2007-11-22 12:53 ` Dmitry Adamushko
2007-11-26 19:44 ` Micah Dowty
2007-11-27 9:21 ` Dmitry Adamushko
2007-11-27 17:13 ` Micah Dowty
2007-11-16 19:13 ` David Newall
2007-11-16 21:38 ` Micah Dowty
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