linux-kernel - Re: I/O throughput problem in newer kernels

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Message-ID: <c5764b870904070558u51ec2e82ob26c8aabb2976f4e@mail.gmail.com>
Date:	Tue, 7 Apr 2009 08:58:34 -0400
From:	Alin Dobra <adobra@...e.ufl.edu>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: I/O throughput problem in newer kernels

Andrew (and other people interestead),

I forgot to mention in the post that I used O_DIRECT for all tests
(including dd tests). The CPU utilization is negligible; keep in mind
that the machine has 32 cores so cpu should not be  problem, or memory
bandwidth for that matter. The think that puzzles me the most is the
fact that the throughput does not level up, it goes down dramatically
(a factor of 3 for 54 hard drives versus 20 hard drives).

Alin

--
Alin Dobra
Assistant Professor
Computer Information Science & Engineering Department
University of Florida
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