From mboxrd@z Thu Jan  1 00:00:00 1970
From: arlie@worldash.org (Arlie Stephens)
Date: Wed, 20 Mar 2013 16:05:09 -0700
Subject: Linux elevators (Re: BFQ: simple elevator)
In-Reply-To: <14506.1363813419@turing-police.cc.vt.edu>
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	<14506.1363813419@turing-police.cc.vt.edu>
Message-ID: <20130320230509.GA11275@worldash.org>
To: kernelnewbies@lists.kernelnewbies.org
List-Id: kernelnewbies.lists.kernelnewbies.org

The ongoing thread reminds me of a simple question I've had since I
first read about linux' mutiple I/O schedulers. Why is the choice of
I/O scheduler global to the whole kernel, rather than per-device or
similar? 

Consider a system with both traditional rotating disks and SSDs - not
at all far fetched. An appropriate I/O scheduling algorithm for
rotating disks is likely to do a lot of work that's useless for
SSDs. Why require that the same algorithms be used for both? 

--
Arlie

(Arlie Stephens					arlie at worldash.org)