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

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.


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 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

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.


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Attachment: qemu-dm-clientw3.log
Description: Text document

Attachment: clientw3.dump.xml
Description: Text Data

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