From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [RFC PATCH 2/2] macvtap: TX zero copy between guest and host kernel Date: Wed, 15 Sep 2010 07:12:41 +0200 Message-ID: <20100915051241.GA25340@redhat.com> References: <1284476719.13351.35.camel@localhost.localdomain> <201009141721.13202.arnd@arndb.de> <20100914152231.GA13105@redhat.com> <1284480025.13351.49.camel@localhost.localdomain> <20100914162952.GB13560@redhat.com> <1284483745.13351.71.camel@localhost.localdomain> <20100914182707.GB15549@redhat.com> <1284490143.13351.82.camel@localhost.localdomain> <20100914190156.GA16037@redhat.com> <1284492983.13351.95.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Arnd Bergmann , Avi Kivity , "Xin, Xiaohui" , David Miller , netdev@vger.kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org To: Shirley Ma Return-path: Content-Disposition: inline In-Reply-To: <1284492983.13351.95.camel@localhost.localdomain> Sender: netdev-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On Tue, Sep 14, 2010 at 12:36:23PM -0700, Shirley Ma wrote: > 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 Yes, I agree this patch is useful for demo purposes: simple, and shows what kind of performance gains we can expect for TX. -- MST