From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=50895 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PSB18-0001lu-MQ for qemu-devel@nongnu.org; Mon, 13 Dec 2010 11:12:51 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1PSB13-0008Fu-DW for qemu-devel@nongnu.org; Mon, 13 Dec 2010 11:12:50 -0500 Received: from mx1.redhat.com ([209.132.183.28]:34767) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1PSB13-0008FW-6G for qemu-devel@nongnu.org; Mon, 13 Dec 2010 11:12:45 -0500 Date: Mon, 13 Dec 2010 18:12:19 +0200 From: "Michael S. Tsirkin" Message-ID: <20101213161219.GA6715@redhat.com> References: <20101212204127.GA24726@redhat.com> <20101212204228.GA24786@redhat.com> <20101212205634.GA24986@redhat.com> <20101212210959.GA25136@redhat.com> <20101213103836.GG25590@redhat.com> <20101213133538.GA2731@redhat.com> <20101213133615.GB2731@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: Content-Transfer-Encoding: quoted-printable Subject: [Qemu-devel] Re: [PATCH v5 0/4] virtio: Use ioeventfd for virtqueue notify List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Stefan Hajnoczi Cc: qemu-devel@nongnu.org On Mon, Dec 13, 2010 at 03:27:06PM +0000, Stefan Hajnoczi wrote: > On Mon, Dec 13, 2010 at 1:36 PM, Michael S. Tsirkin wr= ote: > > On Mon, Dec 13, 2010 at 03:35:38PM +0200, Michael S. Tsirkin wrote: > >> On Mon, Dec 13, 2010 at 01:11:27PM +0000, Stefan Hajnoczi wrote: > >> > Fresh results: > >> > > >> > 192.168.0.1 - host (runs netperf) > >> > 192.168.0.2 - guest (runs netserver) > >> > > >> > host$ src/netperf -H 192.168.0.2 -- -m 200 > >> > > >> > ioeventfd=3Don > >> > TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.0= .2 > >> > (192.168.0.2) port 0 AF_INET > >> > Recv =A0 Send =A0 =A0Send > >> > Socket Socket =A0Message =A0Elapsed > >> > Size =A0 Size =A0 =A0Size =A0 =A0 Time =A0 =A0 Throughput > >> > bytes =A0bytes =A0 bytes =A0 =A0secs. =A0 =A010^6bits/sec > >> > =A087380 =A016384 =A0 =A0200 =A0 =A010.00 =A0 =A01759.25 > >> > > >> > ioeventfd=3Doff > >> > TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.0= .2 > >> > (192.168.0.2) port 0 AF_INET > >> > Recv =A0 Send =A0 =A0Send > >> > Socket Socket =A0Message =A0Elapsed > >> > Size =A0 Size =A0 =A0Size =A0 =A0 Time =A0 =A0 Throughput > >> > bytes =A0bytes =A0 bytes =A0 =A0secs. =A0 =A010^6bits/sec > >> > > >> > =A087380 =A016384 =A0 =A0200 =A0 =A010.00 =A0 =A01757.15 > >> > > >> > The results vary approx +/- 3% between runs. > >> > > >> > Invocation: > >> > $ x86_64-softmmu/qemu-system-x86_64 -m 4096 -enable-kvm -netdev > >> > type=3Dtap,id=3Dnet0,ifname=3Dtap0,script=3Dno,downscript=3Dno -de= vice > >> > virtio-net-pci,netdev=3Dnet0,ioeventfd=3Don|off -vnc :0 -drive > >> > if=3Dvirtio,cache=3Dnone,file=3D$HOME/rhel6-autobench-raw.img > >> > > >> > I am running qemu.git with v5 patches, based off > >> > 36888c6335422f07bbc50bf3443a39f24b90c7c6. > >> > > >> > Host: > >> > 1 Quad-Core AMD Opteron(tm) Processor 2350 @ 2 GHz > >> > 8 GB RAM > >> > RHEL 6 host > >> > > >> > Next I will try the patches on latest qemu-kvm.git > >> > > >> > Stefan > >> > >> One interesting thing is that I put virtio-net earlier on > >> command line. > > > > Sorry I mean I put it after disk, you put it before. >=20 > I can't find a measurable difference when swapping -drive and -netdev. One other concern I have is that we are apparently using ioeventfd for all VQs. E.g. for virtio-net we probably should not use it for the control VQ - it's a waste of resources. > Can you run the same test with vhost? I assume it still outperforms > userspace virtio for small message sizes? I'm interested because that > also uses ioeventfd. >=20 > I am wondering if the iothread differences between qemu.git and > qemu-kvm.git can explain the performance results we see. In > particular, qemu.git produces the same (high) throughput whether > ioeventfd is on or off. >=20 > Stefan