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Subject: Re: [RFC PATCH 2/2] macvtap: TX zero copy between guest and host
 kernel
From: Shirley Ma <mashirle@us.ibm.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>, Avi Kivity <avi@redhat.com>,
        "Xin, Xiaohui" <xiaohui.xin@intel.com>,
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Date: Tue, 14 Sep 2010 12:36:23 -0700
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On Tue, 2010-09-14 at 21:01 +0200, Michael S. Tsirkin wrote:
> > > I think that you should be able to simply combine
> > > the two drivers together, add an ioctl to
> > > enable/disable zero copy mode of operation. 
> > 
> > That could work. But what's the purpose to have two drivers if one
> > driver can handle it?
> > 
> > Thanks
> > Shirley
> 
> This was just an idea: I thought it's a good way for people interested
> in this zero copy thing to combine forces and avoid making
> the same mistakes, but it's not a must of course. 

Ok, I will make a simple patch by reusing Xiaohui's some vhost code on
handling vhost_add_used_and_signal() to see any performance changes.

The interesting thing here when I run 32 instances netperf/netserver I
didn't see any issue w/i this patch.

Thanks
Shirley