From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [v3 RFC PATCH 0/4] Implement multiqueue virtio-net Date: Thu, 28 Oct 2010 08:18:32 +0200 Message-ID: <20101028061832.GA7590@redhat.com> References: <20101025161718.GA19559@redhat.com> <20101026093846.GA6766@redhat.com> <20101026110913.GC7922@redhat.com> <20101028055054.GG5599@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: anthony@codemonkey.ws, arnd@arndb.de, avi@redhat.com, davem@davemloft.net, eric.dumazet@gmail.com, kvm@vger.kernel.org, netdev@vger.kernel.org, netdev-owner@vger.kernel.org, rusty@rustcorp.com.au To: Krishna Kumar2 Return-path: Content-Disposition: inline In-Reply-To: Sender: kvm-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Thu, Oct 28, 2010 at 11:42:05AM +0530, Krishna Kumar2 wrote: > > "Michael S. Tsirkin" > > > > > I think we discussed the need for external to guest testing > > > > over 10G. For large messages we should not see any change > > > > but you should be able to get better numbers for small messages > > > > assuming a MQ NIC card. > > > > > > For external host, there is a contention among different > > > queues (vhosts) when packets are processed in tun/bridge, > > > unless I implement MQ TX for macvtap (tun/bridge?). So > > > my testing shows a small improvement (1 to 1.5% average) > > > in BW and a rise in SD (between 10-15%). For remote host, > > > I think tun/macvtap needs MQ TX support? > > > > Confused. I thought this *is* with a multiqueue tun/macvtap? > > bridge does not do any queueing AFAIK ... > > I think we need to fix the contention. With migration what was guest to > > host a minute ago might become guest to external now ... > > Macvtap RX is MQ but not TX. I don't think MQ TX support is > required for macvtap, though. Is it enough for existing > macvtap sendmsg to work, since it calls dev_queue_xmit > which selects the txq for the outgoing device? > > Thanks, > > - KK I think there would be an issue with using a single poll notifier and contention on send buffer atomic variable. Is tun different than macvtap? We need to support both long term ... -- MST