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Subject: Re: [PATCH 07/41] cpuset: Set up interface for nohz flag
From: Mike Galbraith <efault@gmx.de>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Christoph Lameter <cl@linux.com>, Frederic Weisbecker <fweisbec@gmail.com>,
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Date: Tue, 08 May 2012 21:50:01 +0200
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On Tue, 2012-05-08 at 18:16 +0200, Peter Zijlstra wrote: 
> On Tue, 2012-05-08 at 10:57 -0500, Christoph Lameter wrote:

> isolcpus is a very limited hack that adds more pain that its worth. Its
> yet another mask to check and its functionality is completely available
> through cpusets.

Agreed.

> You cannot create multi-cpu partitions using isolcpus, you cannot
> dynamically reconfigure it.

Big plus for cpusets.

> And on the scheduler side cpusets doesn't add runtime overhead to normal
> things, only sched_setaffinity() and a few other rare operations get
> slightly more expensive. And it allows to reduce runtime overhead by
> making the load-balancer domains smaller.

Very big deal if you have a load that doesn't do all the performance 'i'
dotting and 't' crossing it maybe could have, but ends up on a big box.

-Mike