On 2014/1/28 17:41, Michael S. Tsirkin wrote:

quoted

quoted

I think it's okay - IIUC this way we are processing xmit directly
instead of going through softirq.
Was meaning to try this - I'm glad you are looking into this.

Could you please check latency results?

netperf UDP_RR 512
test model: VM->host->host

modified before : 11108
modified after  : 11480

3% gained by this patch

Nice.
What about CPU utilization?
It's trivially easy to speed up networking by
burning up a lot of CPU so we must make sure it's
not doing that.
And I think we should see some tests with TCP as well, and
try several message sizes.

Yes, by burning up more CPU we could get better performance easily.
So I have bond vhost thread and interrupt of nic on CPU1 while testing.

modified before, the idle of CPU1 is 0%-1% while testing.
and after modify, the idle of CPU1 is 2%-3% while testing

TCP also could gain from this, but pps is less than UDP, so I think the 
improvement would be not so obviously.