Subject: Re: virtio-net zero-copy

From: Avi Kivity <[email-masked]>
Date: Mon, 18 May 2009 17:00:14 +0300

Raju Srivastava wrote:
> Greetings,
>
> Could someone let me know if current virtio-net supports zero-copy? I
> see some discussion here:
> http://thread.gmane.org/gmane.comp.emulators.kvm.devel/28061/
> (copyless virtio net thoughts) and it looks like the copyless
> virtio-net is not supported by KVM yet. 

That is correct.

> If this is true, then is there
> any plan to add the zero copy to the virtio-net?
>   

Yes, but it will be a difficult journey.

> I use KVM in 10G network environment and found the CPU usage is
> saturated when network traffic becomes heavy. The native Linux under
> the same load only consumes less than 10% CPU.
>   

Running the latest guest and host software (both qemu and kernel) will 
improve things somewhat.

-- 
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