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

[Pasi Kärkkäinen <pasik@xxxxxx>]

On Sun, Apr 11, 2010 at 05:39:27PM +0200, Fabiano Francesconi wrote:
> On Sun, Apr 11, 2010 at 02:55:24PM +0100, Andrew Lyon wrote:
> > On Sun, Apr 11, 2010 at 11:30 AM, Fabiano Francesconi
> > <fabiano.francesconi@xxxxxxxxx> wrote:
> > > Hello there,
> > > I'm noticing a performance regression for what's matter the hard-disk I
> > > pass to the domU (aquaria).
> > 
> > 
> > Have you checked the performance of the disk in dom0?
> > 
> > >
> > > The slow-down is very noticeable even when moving small videos file
> > > (~350mb).
> > >
> > > In the configuration file of the domU, I pass the whole disk
> > > ('phy:/dev/sdb,xvdb,w') to the guest OS.
> > >
> > > The distribution under both systems is Gentoo/Linux, x86 arch.
> > >
> > > The hypervisor is always the same, in both scenarios (Linux xevelon
> > > 2.6.32-xen-r1 #1 SMP Sat Apr 10 13:37:02 CEST 2010 i686 Intel(R)
> > > Atom(TM) CPU 330 @ 1.60GHz GenuineIntel GNU/Linux).
> > >
> > > The machine is an Atom, so it's not capable of any VT technology but so
> > > far it's a great machine and XEN is working just fine on it.
> > >
> > > I attach you few logs I've gathered.
> > >
> > > Thank you
> > >
> > > --
> > > Fabiano Francesconi [GPG key: 0x81E53461]
> > >
> > > _______________________________________________
> > > Xen-users mailing list
> > > Xen-users@xxxxxxxxxxxxxxxxxxx
> > > http://lists.xensource.com/xen-users
> > >
> 
> It seems, actually, that something has changed since the performance
> seems to be restored back to the normality.
> 
> Mh, I can't explain that.. maybe I had some process keep running CPU
> high while I was performing that hdparm.
> 
> I'll keep this thread up-to-date if something changes again.
> 
> Sorry for this bad report.
> 

Have you read this wiki page?:
http://wiki.xensource.com/xenwiki/XenBestPractices

Might help.

-- Pasi


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