Re: Poor performance with virtio network driver on windows 2008 R2 on KVM

[Peter Kieser <peter@kieser.ca>]

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Hi JR,

I mostly did this to stop the freezing. I'm back to troubleshoot this 
issue, since the e1000 driver performs worse with Linux 3.10 and qemu 
2.0 now. One thing that did help a bit, was disabling vhost-net zero 
copy, but the latency and packet loss is still there (but not as much.)

Did you come up with anything?

-Peter

On 2014-05-15 11:01 AM, JR wrote:
> Hi Peter,
>
> Thanks for the advise.  How does the intel driver perform?  Wirespeed
> range?  (Or, did you make the change more to fix the freezing rather
> than to up the performance?)
>
> Thanks
> JR
>
> On 5/15/2014 1:27 PM, Peter Kieser wrote:
>> On 2014-05-14 8:37 AM, JR wrote:
>>> Greetings all,
>>>
>>> Though I don't believe that this is KVM problem per se, I'm seeing very
>>> poor network performance when using windows 2008R2 KVM instances with
>>> the virtio driver when on a 10G network.  iperf results show linux VMs
>>> getting close to wire speeds, while windows only does about 1.3Gb/sec.
>>>
>>> I've tried a number of tcp settings (chimney, etc...) as recommended by
>>> some google searches but nothing has helped.
>>>
>>> Does anyone have any advice?
>>>
>>> Thanks much,
>>> JR
>>>
>>>
>> I ran into similar issues with the Redhat virtio drivers, and the guest
>> would freeze with high transfer. I switched to the emulated e1000 NIC
>> and haven't had any problems since.
>>
>> -Peter
>>



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