From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH 0/3] qemu-kvm: vhost net support Date: Wed, 12 Aug 2009 20:35:48 +0300 Message-ID: <20090812173548.GA29981@redhat.com> References: <20090810192304.GA16781@redhat.com> <4A808840.70704@codemonkey.ws> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: avi@redhat.com, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org To: Anthony Liguori Return-path: Received: from mx2.redhat.com ([66.187.237.31]:37816 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754653AbZHLRhG (ORCPT ); Wed, 12 Aug 2009 13:37:06 -0400 Content-Disposition: inline In-Reply-To: <4A808840.70704@codemonkey.ws> Sender: kvm-owner@vger.kernel.org List-ID: On Mon, Aug 10, 2009 at 03:51:12PM -0500, Anthony Liguori wrote: > Michael S. Tsirkin wrote: >> This adds support for vhost-net virtio kernel backend. >> >> This is RFC, but works without issues for me. >> >> Still needs to be split up, tested and benchmarked properly, >> but posting it here in case people want to test drive >> the kernel bits I posted. >> > > Any rough idea on performance? Better or worse than userspace? > > Regards, > > Anthony Liguori Well, I definitely see some gain in latency. Here's a simple test over a 1G ethernet link (host to guest): Native: [root@qus18 ~]# netperf -H 11.0.0.1 -t udp_rr UDP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 11.0.0.1 (11.0.0.1) port 0 AF_INET Local /Remote Socket Size Request Resp. Elapsed Trans. Send Recv Size Size Time Rate bytes Bytes bytes bytes secs. per sec 126976 126976 1 1 10.00 10393.23 124928 124928 vhost virtio: [root@qus18 ~]# netperf -H 11.0.0.3 -t udp_rr UDP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 11.0.0.3 (11.0.0.3) port 0 AF_INET Local /Remote Socket Size Request Resp. Elapsed Trans. Send Recv Size Size Time Rate bytes Bytes bytes bytes secs. per sec 126976 126976 1 1 10.00 8169.58 124928 124928 Userspace virtio: [root@qus18 ~]# netperf -H 11.0.0.3 -t udp_rr UDP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 11.0.0.3 (11.0.0.3) port 0 AF_INET Local /Remote Socket Size Request Resp. Elapsed Trans. Send Recv Size Size Time Rate bytes Bytes bytes bytes secs. per sec 126976 126976 1 1 10.00 2029.49 124928 124928 Part of it might be that tx mitigation does not come into play with vhost. I need to disable it in qemu and see. -- MST