Date: Sat, 23 Jan 2010 12:35:51 +0100
From: Andi Kleen <andi@firstfloor.org>
To: Dave Chinner <david@fromorbit.com>
Cc: Andi Kleen <andi@firstfloor.org>, Don Mullis <don.mullis@gmail.com>,
       linux-kernel@vger.kernel.org, airlied@redhat.com,
       dedekind@infradead.org
Subject: Re: [PATCH 1/2] lib: more scalable list_sort()
Message-ID: <20100123113551.GB29555@one.firstfloor.org>
References: <87fx609i29.fsf@gmail.com> <20100121175914.GA8910@basil.fritz.box> <87vdeu96bo.fsf@gmail.com> <87k4vah12u.fsf@basil.nowhere.org> <20100123082839.GB25842@discord.disaster>
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> Burning CPU time to save on IO is a very valid tradeoff in
> filesystem design - burning a few hundred millieseconds of CPU
> time can result in savcwinge tens of seconds of IO time. Hence
> passing big long lists to be sorted is not an indication of broken
> design, it's an indication of understanding CPU time vs IO time
> tradeoffs during design...

Burning long CPU time in kernel code without latency breaker code is always
a sign of broken design. When you burn you have to check for 
reschedules. It's that simple.

-Andi

-- 
ak@linux.intel.com -- Speaking for myself only.
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