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Date: Mon, 16 Apr 2007 09:28:24 -0500
From: Matt Mackall <mpm@selenic.com>
To: Nick Piggin <npiggin@suse.de>
Cc: Ingo Molnar <mingo@elte.hu>, Con Kolivas <kernel@kolivas.org>,
       Peter Williams <pwil3058@bigpond.net.au>, linux-kernel@vger.kernel.org,
       Linus Torvalds <torvalds@linux-foundation.org>,
       Andrew Morton <akpm@linux-foundation.org>,
       Mike Galbraith <efault@gmx.de>, Arjan van de Ven <arjan@infradead.org>,
       Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [Announce] [patch] Modular Scheduler Core and Completely Fair Scheduler [CFS]
Message-ID: <20070416142823.GX11115@waste.org>
References: <20070413202100.GA9957@elte.hu> <200704151327.13589.kernel@kolivas.org> <20070415150536.GA6623@elte.hu> <20070415200535.GC11166@waste.org> <20070415204824.GA25813@elte.hu> <20070415213153.GW11115@waste.org> <20070416030349.GB13626@wotan.suse.de>
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On Mon, Apr 16, 2007 at 05:03:49AM +0200, Nick Piggin wrote:
> I'd prefer if we kept a single CPU scheduler in mainline, because I
> think that simplifies analysis and focuses testing.

I think you'll find something like 80-90% of the testing will be done
on the default choice, even if other choices exist. So you really
won't have much of a problem here.

But when the only choice for other schedulers is to go out-of-tree,
then only 1% of the people will try it out and those people are
guaranteed to be the ones who saw scheduling problems in mainline.
So the alternative won't end up getting any testing on many of the
workloads that work fine in mainstream so their feedback won't tell
you very much at all.

-- 
Mathematics is the supreme nostalgia of our time.