From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: vhost-net patches Date: Sun, 25 Oct 2009 12:52:20 +0200 Message-ID: <20091025105220.GA9909@redhat.com> References: <20091022123456.GA6682@redhat.com> <20091022131332.GB6961@redhat.com> <1256232224.6601.17.camel@localhost.localdomain> <20091022174344.GA10821@redhat.com> <1256234420.27706.5.camel@w-sridhar.beaverton.ibm.com> <20091023110438.GA20229@redhat.com> <1256310168.4443.2.camel@localhost.localdomain> <1256310765.4443.4.camel@localhost.localdomain> <1256315020.4443.12.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Sridhar Samudrala , Shirley Ma , David Stevens , kvm@vger.kernel.org, sri@linux.vnet.ibm.com, mashirle@linux.vnet.ibm.com To: Shirley Ma Return-path: Received: from mx1.redhat.com ([209.132.183.28]:11097 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753255AbZJYKyi (ORCPT ); Sun, 25 Oct 2009 06:54:38 -0400 Content-Disposition: inline In-Reply-To: <1256315020.4443.12.camel@localhost.localdomain> Sender: kvm-owner@vger.kernel.org List-ID: On Fri, Oct 23, 2009 at 09:23:40AM -0700, Shirley Ma wrote: > Hello Michael, > > Some initial vhost test netperf results on my T61 laptop from the > working tap device are here, latency has been significant decreased, but > throughput from guest to host has huge regression. Could you please try adding ,sndbuf=0 to tap options, and re-testing? This would make the -net option look like something like this: -net tap,vlan=1,ifname=msttap0,script=/home/mst/ifup,downscript=no,sndbuf=0 > I also hit guest skb_xmit panic. I have not seen panics in a while. Could you provide more information please? Is the panic reproducible? Do you see one of these messages: id %u out of range id %u is not a head! > > netperf TCP_STREAM, default setup, 60 secs run > > guest->host drops from 3XXXMb/s to 1XXXMb/s (regression) > host->guest increases from 3XXXMb/s to 4XXXXMb/s > > TCP_RR, 60 secs run (very impressive) > > guest->host trans/s increases from 2XXX/s to 13XXX/s > host->guest trans/s increases from 2XXX/s to 13XXX/s > > Thanks > Shirley >