Subject: Re: [net-next RFC V4 PATCH 0/4] Multiqueue virtio-net

From: John Fastabend <[email-masked]>
Date: Mon, 25 Jun 2012 07:13:43 -0700

On 6/25/2012 3:07 AM, Michael S. Tsirkin wrote:
> On Mon, Jun 25, 2012 at 05:16:48PM +0800, Jason Wang wrote:
>> Hello All:
>>
>> This series is an update version of multiqueue virtio-net driver based on
>> Krishna Kumar's work to let virtio-net use multiple rx/tx queues to do the
>> packets reception and transmission. Please review and comments.
>>
>> Test Environment:
>> - Intel(R) Xeon(R) CPU E5620 @ 2.40GHz, 8 cores 2 numa nodes
>> - Two directed connected 82599
>>
>> Test Summary:
>>
>> - Highlights: huge improvements on TCP_RR test
>> - Lowlights: regression on small packet transmission, higher cpu utilization
>>               than single queue, need further optimization
>
> Didn't review yet, reacting this this paragraph:
>
> To avoid regressions, it seems reasonable to make
> the device use a single queue by default for now.
> Add a way to switch multiqueue on/off using ethtool.
>
> This way guest admin can tune the device for the
> workload manually until we manage to imlement some
> self-tuning heuristics.
>

Ethtool already has this switch 'ethtool -L' can be
used to set the number tx/rx channels. So you would
likely just need to add a set_channels hook.

.John