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Re: [Xen-users] Xen hard-disk performance regression?

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Subject: Re: [Xen-users] Xen hard-disk performance regression?
From: "Olivier B." <xen.list@xxxxxxxxx>
Date: Mon, 12 Apr 2010 01:01:38 +0200
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Are you using LVM ? Barriers was implemented on LVM in recent versions, which can probably explain some performance regressions like this.


On 11/04/2010 21:44, Fabiano Francesconi wrote:
Ok, confirmed. The problem is only visible when copying files so it's
not something related to the hard-disk itself.

I sincerely don't know how to dig into this but I have made some tests

I've tried copying a single avi file (350mb) from one partition to
another one. Both partition are on the same device (WDC WD10EADS-00M2B0)
and both formatted in XFS filesystem.

Running 2.6.32-xen-r1 I have the following output:

real    1m35.001s
user    0m0.016s
sys     0m0.722s

Running 2.6.29-xen-r4 I have, instead, the following output:

real    0m20.689s
user    0m0.018s
sys     0m2.047s

How can I see such a difference? Is there some known regression for XFS
filesystem? I might try to run a vanilla kernel instead of a xen-patched

Any suggestion will be very much appreciated.

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