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Subject: Re: [PATCH 07/41] cpuset: Set up interface for nohz flag
From: Mike Galbraith <efault@gmx.de>
To: Christoph Lameter <cl@linux.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
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Date: Wed, 09 May 2012 17:33:42 +0200
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On Wed, 2012-05-09 at 10:05 -0500, Christoph Lameter wrote:

> I do not get how a cpuset could be used by an application with load
> balancing disabled. Seems to defeat the purpose of the cpuset (which IMHO
> is to generate a custom load balancing domain after all). You would
> have to manually pin the processes to processors of the cpuset anyways.
> 
> If you already have to pin then why would you want a cpuset on top of
> that?

You don't have to turn load balancing completely off.  I have at least
one customer with modest isolation requirements, an exclusive set with
load balancing enabled is perfect for them.  OTOH, for tight constraint
RT, I have no choice but to turn everything I can get my hands on off.
Any such app manages itself or is busted crud, so all is well, cpusets
work nicely.

I don't like cgroups much, but I've become rather fond of cpusets.

-Mike