>From: Michael S. Tsirkin [mailto:mst@xxxxxxxxxx] >Sent: Wednesday, September 15, 2010 12:30 AM >To: Shirley Ma >Cc: Arnd Bergmann; Avi Kivity; Xin, Xiaohui; David Miller; netdev@xxxxxxxxxxxxxxx; >kvm@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx >Subject: Re: [RFC PATCH 2/2] macvtap: TX zero copy between guest and host kernel > >On Tue, Sep 14, 2010 at 09:00:25AM -0700, Shirley Ma wrote: >> On Tue, 2010-09-14 at 17:22 +0200, Michael S. Tsirkin wrote: >> > I would expect this to hurt performance significantly. >> > We could do this for asynchronous requests only to avoid the >> > slowdown. >> >> Is kiocb in sendmsg helpful here? It is not used now. >> >> Shirley > >Precisely. This is what the patch from Xin Xiaohui does. That code >already seems to do most of what you are trying to do, right? > >The main thing missing seems to be macvtap integration, so that we can fall back >on data copy if zero copy is unavailable? >How hard would it be to basically link the mp and macvtap modules >together to get us this functionality? Anyone? > Michael, Is to support macvtap with zero-copy through mp device the functionality you mentioned above? Before Shirley Ma has suggested to move the zero-copy functionality into tun/tap device or macvtap device. How do you think about that? I suspect there will be a lot of duplicate code in that three drivers except we can extract code of zero-copy into kernel APIs and vhost APIs. Do you think that's worth to do and help current process which is blocked too long than I expected? > >-- >MST -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
