Re: Binary Windows guest drivers are released

[Vadim Rozenfeld <vrozenfe@redhat.com>]

On 09/25/2009 10:53 AM, Kenni Lund wrote:
> 2009/9/25 Vadim Rozenfeld<vrozenfe@redhat.com>:
>    
>> On 09/25/2009 12:07 AM, Dor Laor wrote:
>>      
>>> 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.
>>>>
>>>>          
>>> 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?
>>> Dor
>>>        
>> Windows XP 32-bit virtio block driver was created from our mainline code
>> almost for fun.
>> Not like our mainline code, which is STORPORT oriented, it is a SCSIPORT
>> (!!!!) mini-port driver.
>> SCSIPORT has never been known as I/O optimized storage stack.
>> SCSIPORT architecture is almost dead officially.
>> Windows XP 32-bit has no support for STORPORT or virtual storage stack.
>>      
> Ok, in that case, wouldn't it be better simply not to build the XP driver and
> instead put a note somewhere (in the wiki?), saying that it doesn't make
> sense to use VirtIO on XP due to these reasons?
>    
I have no idea what was the reason for building and announcing XP 32bit 
driver.
I mean, technically it is possible. You can also expect less CPU 
consumption by switching
to SCSIPORT virtio driver. But please don't expect any significant 
performance burst.
>    
>> Developing monolithic disk driver, which will sit right on top of virtio-blk
>> PCI device, looks like the one way
>> to have some kind of high throughput storage for Windows XP 32-bit.
>>      
> Ok, since these drivers are targeted Windows Server and XP is getting old,
> I suppose no efforts will be put into developing such driver, or?
>    
I don't know, but why not? It shouldn't be too complicated.
> Best Regards,
> Kenni
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