From: "Alan D. Brunelle" <Alan.Brunelle@hp.com>
To: Corrado Zoccolo <czoccolo@gmail.com>
Cc: Vivek Goyal <vgoyal@redhat.com>,
linux-kernel@vger.kernel.org, jens.axboe@oracle.com
Subject: Re: [RFC] Block IO Controller V2 - some results
Date: Tue, 17 Nov 2009 11:45:00 -0500 [thread overview]
Message-ID: <1258476300.6084.104.camel@cail> (raw)
In-Reply-To: <4e5e476b0911170817s39286103g3796f25cba9f623c@mail.gmail.com>
On Tue, 2009-11-17 at 17:17 +0100, Corrado Zoccolo wrote:
> Hi Vivek,
> the performance drop reported by Alan was my main concern about your
> approach. Probably you should mention/document somewhere that when the
> number of groups is too large, there is large decrease in random read
> performance.
>
> However, we can check few things:
> * is this kernel built with HZ < 1000? The smallest idle CFQ will do
> is given by 2/HZ, so running with a small HZ will increase the impact
> of idling.
FYI:
CONFIG_NO_HZ=y
CONFIG_HZ_1000=y
CONFIG_HZ=1000
next prev parent reply other threads:[~2009-11-17 16:44 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-16 20:51 [RFC] Block IO Controller V2 - some results Alan D. Brunelle
2009-11-16 21:14 ` Vivek Goyal
2009-11-16 21:32 ` Alan D. Brunelle
2009-11-16 21:37 ` Vivek Goyal
2009-11-16 22:18 ` Vivek Goyal
2009-11-17 12:38 ` Alan D. Brunelle
2009-11-17 14:14 ` Vivek Goyal
2009-11-17 16:17 ` Corrado Zoccolo
2009-11-17 16:40 ` Vivek Goyal
2009-11-17 17:30 ` Alan D. Brunelle
2009-11-17 17:44 ` Vivek Goyal
2009-11-17 20:59 ` Corrado Zoccolo
2009-11-17 22:38 ` Vivek Goyal
2009-11-17 23:11 ` Corrado Zoccolo
2009-11-19 0:04 ` Vivek Goyal
2009-11-19 20:12 ` Corrado Zoccolo
2009-11-17 16:45 ` Alan D. Brunelle [this message]
2009-11-18 15:32 ` Vivek Goyal
2009-11-18 16:20 ` Corrado Zoccolo
2009-11-18 22:56 ` Vivek Goyal
2009-11-18 23:35 ` Corrado Zoccolo
2009-11-20 14:18 ` Vivek Goyal
2009-11-20 14:28 ` Corrado Zoccolo
2009-11-20 15:04 ` Vivek Goyal
2009-11-20 18:32 ` Corrado Zoccolo
2009-11-20 18:42 ` Vivek Goyal
2009-11-20 19:50 ` Corrado Zoccolo
2009-11-21 17:57 ` Corrado Zoccolo
2009-11-23 15:19 ` Vivek Goyal
2009-11-23 16:22 ` Corrado Zoccolo
2009-11-17 20:38 ` Alan D. Brunelle
2009-11-19 16:57 ` Vivek Goyal
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