From: Tracy Reed <treed@ultraviolet.org>
To: "Pasi Kärkkäinen" <pasik@iki.fi>
Cc: xen-devel@lists.xensource.com,
Aoetools-discuss@lists.sourceforge.net,
linux-kernel@vger.kernel.org
Subject: Re: [Xen-devel] domU is causing misaligned disk writes
Date: Tue, 20 Apr 2010 13:03:10 -0700 [thread overview]
Message-ID: <20100420200310.GR5660@tracyreed.org> (raw)
In-Reply-To: <20100420195442.GC1878@reaktio.net>
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On Tue, Apr 20, 2010 at 10:54:42PM +0300, Pasi Kärkkäinen spake thusly:
> Please try with "bs=1024k" and maybe with "bs=64k" aswell.
>
> 4k blocksize transfer will always be slower in domU than in dom0
> since virtual disk abstraction makes some overhead, which is more
> visible with small blocksizes.
But overhead in domU wouldn't be causing all of these reads. I am
doing a test with bs=64k now:
Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz
avgqu-sz await svctm %util
sda 0.00 3258.20 964.00 54.00 3903.20 13652.80
34.49 2.75 2.71 0.68 68.88
sdb 0.00 3270.20 974.80 54.00 3940.80 13710.40
34.31 2.42 2.38 0.55 56.22
> So the speed is the same to the partitioned disk than to the raw disk?
> What disk backend are you using in dom0? phy:? tap:aio: ?
Yes.
I am using phy: disk backend. Should I be using something else?
--
Tracy Reed
http://tracyreed.org
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next prev parent reply other threads:[~2010-04-20 20:03 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-20 8:09 domU is causing misaligned disk writes Tracy Reed
2010-04-20 8:09 ` Tracy Reed
2010-04-20 8:49 ` [Xen-devel] " Pasi Kärkkäinen
2010-04-20 8:49 ` Pasi Kärkkäinen
2010-04-20 8:54 ` [Xen-devel] " Pasi Kärkkäinen
2010-04-20 8:54 ` Pasi Kärkkäinen
2010-04-20 18:40 ` [LKML] " Konrad Rzeszutek Wilk
2010-04-20 22:58 ` [LKML] Re: [Xen-devel] " Tracy Reed
2010-04-20 19:39 ` Tracy Reed
2010-04-20 19:39 ` Tracy Reed
2010-04-20 19:54 ` [Xen-devel] " Pasi Kärkkäinen
2010-04-20 19:54 ` Pasi Kärkkäinen
2010-04-20 20:03 ` Tracy Reed [this message]
2010-04-20 20:00 ` [Xen-devel] " Tracy Reed
2010-04-20 20:25 ` Konrad Rzeszutek Wilk
2010-04-20 21:19 ` Tracy Reed
2010-04-20 21:19 ` Tracy Reed
2010-04-28 19:55 ` [Aoetools-discuss] [Xen-devel] " Gabor Gombas
2010-04-28 19:55 ` Gabor Gombas
2010-04-20 20:41 ` Brendan Cully
2010-04-20 20:41 ` Brendan Cully
2010-04-20 21:58 ` [Xen-devel] " Tracy Reed
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