From: Andi Kleen <ak@suse.de>
To: Ian Pratt <m+Ian.Pratt@cl.cam.ac.uk>
Cc: "Graham, Simon" <Simon.Graham@stratus.com>,
xen-devel@lists.xensource.com
Subject: Re: Re: Reducing impact of save/restore/dump on Dom0
Date: Wed, 7 Feb 2007 13:58:27 +0100 [thread overview]
Message-ID: <200702071358.27540.ak@suse.de> (raw)
In-Reply-To: <8A87A9A84C201449A0C56B728ACF491E04F480@liverpoolst.ad.cl.cam.ac.uk>
> It's pretty easy for us to arrange that everything is page aligned. If
> there was a measurable performance advantage using o_direct rather than
> madvise/fadvise it probably makes sense to use it -- I can't see
> o_direct going away any time soon.
O_DIRECT won't do any write behind, so unless you do very aggressive IO
(large IO requests, threads or aio so you do useful work during the disk write
latency) it will be likely slower. Similar for read -- it won't do any
readahead which you would need to do by yourself.
It's really not a very good idea for most non database applications.
-Andi
next prev parent reply other threads:[~2007-02-07 12:58 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-02-06 15:43 Reducing impact of save/restore/dump on Dom0 Graham, Simon
2007-02-06 16:23 ` John Levon
2007-02-06 17:36 ` Iustin Pop
2007-02-06 17:46 ` Graham, Simon
2007-02-06 18:35 ` Iustin Pop
2007-02-06 23:00 ` Ian Pratt
2007-02-06 23:20 ` Jeremy Fitzhardinge
2007-02-07 6:40 ` Rusty Russell
2007-02-07 7:41 ` Jeremy Fitzhardinge
2007-02-07 12:11 ` Andi Kleen
2007-02-07 12:52 ` Ian Pratt
2007-02-07 12:58 ` Andi Kleen [this message]
-- strict thread matches above, loose matches on Subject: below --
2007-02-07 13:06 Graham, Simon
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