Re: [Xen-users] Windows PV drivers destroying performance

[Graham Crowe <graham@xxxxxxxxxx>]

My config and qemu logs are attached. There is one rather telling line 
in the qemu log...
"Unknown PV product 2 loaded in guest"

I suspect it may be because I am using an old version of the PV drivers 
(the most recent sites are offline, so I used an older one)
Is anyone able to point me to the latest PV drivers to try (WinXP, Win7 
32 bit and Win7 64 bit)?
As for the suggestion that I roll back to a snapshot. This is basically 
a fresh Windows install (I am just only starting a trial of Windows VMs 
- I already have a number of Linux VMs) so a snapshot won't help me much.
Thanks



On 24/07/2015 11:35 PM, Ian Campbell wrote:
> On Fri, 2015-07-24 at 22:14 +1000, G Crowe wrote:
> > I installed the PV drivers in some windows PVs as I thought it would
> > improve performance, but the systems then became painfully slow to use.
> >
> > I ran some tests on hard disc performance on a newly installed Win7 32
> > bit system before and after installing the PV drivers from univention.de
> > (version 0.11.0.373) as the other sites appear to be offline. The host
> > machine is running Fedora 21 with kernel 3.19.3.
> > Without the PV drivers (with QEMU hardware) hard disc performance was
> > 4409 I/O per second and 9.03Mbps.
> > With the PV drivers installed this dropped to 207 I/O per second and
> > 0.43Mbps.
> >
> > Without the PV drivers, the remote desktop screen would refresh almost
> > instantly, but with the PV drivers it could take up to 10 seconds just
> > to refresh the screen.
> >
> > I don't understand this, as I though that the sole purpose of the PV
> > drivers was to improve I/O performance,
> Your expectation here is correct.
>
> >   yet they have made the system so
> > slow that it is virtually unusable.
> >
> > Am I doing something wrong here?
> It seems unlikely, I don't think there is much you can have done wrong,
> it's supposed to just work ;-) more likely some sort of bad interaction
> between some (possibly buggy) component and another.
>
> I don't know much about the Windows PV drivers, so hopefully someone else
> can chip in with some tips/knowledge.
>
> Seeing your guest cfg file and any relevant logs from /var/log/xen might
> have some sort of clue.
>
> Ian.
>
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Attachment: qemu-dm-clientw3.log
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Attachment: clientw3.dump.xml
Description: Text Data

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