Re: Binary Windows guest drivers are released

[Dor Laor <dlaor@redhat.com>]

On 09/24/2009 11:59 PM, Javier Guerra wrote:
> On Thu, Sep 24, 2009 at 3:38 PM, Kenni Lund<kenni@kelu.dk>  wrote:
>> I've done some benchmarking with the drivers on Windows XP SP3 32bit,
>> but it seems like using the VirtIO drivers are slower than the IDE drivers in
>> (almost) all cases. Perhaps I've missed something or does the driver still
>> need optimization?
>
> very interesting!
>
> it seems that IDE wins on all the performance numbers, but VirtIO
> always has lower CPU utilization.  i guess this is guest CPU %, right?
> it would also be interesting to compare the CPU usage from the host
> point of view, since a lower 'off-guest' CPU usage is very important
> for scaling to many guests doing I/O.
>

Can you re-try it with setting the host ioscheduler to deadline?
Virtio backend (thread pool) is sensitive for it.

These drivers are mainly tweaked for win2k3 and win2k8. We once had 
queue depth settings in the driver, not sure we still have it, Vadim, 
can you add more info?

Also virtio should provide IO parallelism as opposed to IDE. I don't 
think your test test it. Virtio can provide more virtual drives than the 
max 4 that ide offers.

Dor