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Date: Mon, 19 Dec 2011 16:09:49 +0000
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Peter Zijlstra <peterz@infradead.org>
Cc: "Nikunj A. Dadhania" <nikunj@linux.vnet.ibm.com>, mingo@elte.hu,
        linux-kernel@vger.kernel.org, vatsa@linux.vnet.ibm.com,
        bharata@linux.vnet.ibm.com,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        paulus <paulus@samba.org>
Subject: Re: [RFC PATCH 0/4] Gang scheduling in CFS
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On Mon, 19 Dec 2011 16:51:41 +0100
Peter Zijlstra <peterz@infradead.org> wrote:

> On Mon, 2011-12-19 at 14:03 +0530, Nikunj A. Dadhania wrote:
> > The following patches implements gang scheduling. These patches
> >     are *highly* experimental in nature and are not proposed for
> >     inclusion at this time.
> 
> Nor will they ever be, I've always strongly opposed the whole concept
> and I'm not about to change my mind. Gang scheduling is a scalability
> nightmare. 

For most situations: I think the question is whether you can write a
clean gang scheduling option which has no impact on "normal" users. 

Yes gang scheduling is insane but for some insane workloads its the right
thing to do.

Alan