Re: [rfc net-next v6 0/3] Multiqueue virtio-net

[Jason Wang]

On 10/31/2012 03:05 AM, Rick Jones wrote:
> On 10/30/2012 03:03 AM, Jason Wang wrote:
> > Hi 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.
> >
> > Changes from v5:
> > - Align the implementation with the RFC spec update v4
> > - Switch the mode between single mode and multiqueue mode without reset
> > - Remove the 256 limitation of queues
> > - Use helpers to do the mapping between virtqueues and tx/rx queues
> > - Use commbined channels instead of separated rx/tx queus when do the 
> > queue
> > number configuartion
> > - Other coding style comments from Michael
> >
> > Reference:
> > - A protype implementation of qemu-kvm support could by found in
> > git://github.com/jasowang/qemu-kvm-mq.git
> > - V5 could be found at http://lwn.net/Articles/505388/
> > - V4 could be found at https://lkml.org/lkml/2012/6/25/120
> > - V2 could be found at http://lwn.net/Articles/467283/
> > - Michael virtio-spec: 
> > http://www.spinics.net/lists/netdev/msg209986.html
> >
> > Perf Numbers:
> >
> > - Pktgen test shows the receiving capability of the multiqueue 
> > virtio-net were
> >    dramatically improved.
> > - Netperf result shows latency were greately improved according to 
> > the test
> > result.
>
> I suppose it is technically correct to say that latency was improved, 
> but usually for aggregate request/response tests I tend to talk about 
> the aggregate transactions per second.

Sure.
> Do you have a hypothesis as to why the improvement dropped going to 20 
> concurrent sessions from 10?
>
> rick jones 

I'm investigating this issuse currently, but with no much ideas. The 
aggregate transactions per second scales pretty well even with 20 
cocurrent sessions when doing test between a local host and a local vm. 
Looks like some bottleneck were reached when doing testing over 10gb or 
vms as even if I increase the number of sessions, the result would not 
increase.
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