Message-ID: <4ABC28DE.7050809@datenparkplatz.de>
Date: Fri, 25 Sep 2009 04:20:14 +0200
From: Ulrich Lukas <stellplatz-nr.13a@datenparkplatz.de>
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To: Vivek Goyal <vgoyal@redhat.com>
CC: linux-kernel@vger.kernel.org, containers@lists.linux-foundation.org
Subject: Re: IO scheduler based IO controller V10
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Vivek Goyal wrote:
> Notes:
> - With vanilla CFQ, random writers can overwhelm a random reader.
>   Bring down its throughput and bump up latencies significantly.


IIRC, with vanilla CFQ, sequential writing can overwhelm random readers,
too.

I'm basing this assumption on the observations I made on both OpenSuse
11.1 and Ubuntu 9.10 alpha6 which I described in my posting on LKML
titled: "Poor desktop responsiveness with background I/O-operations" of
2009-09-20.
(Message ID: 4AB59CBB.8090907@datenparkplatz.de)


Thus, I'm posting this to show that your work is greatly appreciated,
given the rather disappointig status quo of Linux's fairness when it
comes to disk IO time.

I hope that your efforts lead to a change in performance of current
userland applications, the sooner, the better.


Thanks
Ulrich
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