From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Fjellstrom Subject: Re: Very bad Speed with Virtio-net Date: Fri, 8 Jan 2010 13:10:47 -0700 Message-ID: <201001081310.47993.tfjellstrom@shaw.ca> References: <4B45BCEA.1040709@googlemail.com> <4B45C3D4.8010800@cnaf.infn.it> Reply-To: tfjellstrom@shaw.ca Mime-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Cc: Riccardo Veraldi , Benjamin Schweikert , Andrea Chierici To: kvm@vger.kernel.org Return-path: Received: from idcmail-mo2no.shaw.ca ([64.59.134.9]:27312 "EHLO idcmail-mo2no.shaw.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753934Ab0AHUKu (ORCPT ); Fri, 8 Jan 2010 15:10:50 -0500 In-Reply-To: <4B45C3D4.8010800@cnaf.infn.it> Sender: kvm-owner@vger.kernel.org List-ID: On Thu January 7 2010, Riccardo Veraldi wrote: > I have similar results, like yours, using CentOS 5.4 x86_64 > I do not think it is possible to gain more than this right now... or > better I wish it could be possible > > If you can get better result please let me know I get 600-800Mbits/s via virtio, the actual speed depends on the direction of traffic.. And if I setup the guest as the iperf server, and the host as the client, I get upwards of 1.2Gbits/s. With some tweaking it might improve throughput, but might harm latency and such, and none of my guests need anywhere near that kind of throughput, but do appreciate lower latency, so I'm keeping it as it is :) > Rick > > Benjamin Schweikert wrote: > > Hello everybody, > > this is my first post on a mailing list, so i hope everything works > > fine. > > > > My host is a AMD X2 4850e with a 64bit Gentoo (unstable). I have > > tested qemu-kvm 0.11, 0.12.x and the git version from the 6. jan. > > I created my own bridges, so i dont need the option from libvirt. I > > bridged a 1 Gb lan card for my VMs. When I use the virtio net driver, > > i get something about 200-300 mbit form my desktop to one if my VMs. > > If iI use the e1000 driver instead of the virtio I get about > > 500 - 600 mbit. > > I tested this with the following kernels: > > Host: 2.6.31.6, 2.6.32.1, 2.6.32.2 > > Guests: 2.6.26, 2.6.30, 2.6.32 (debian) > > 2.6.32 (gentoo) > > > > Here is a default result, virtio vs. e1000: > > > > iperf -c 192.168.0.3 -w 512k -l 512k > > ------------------------------------------------------------ > > Client connecting to 192.168.0.3, TCP port 5001 > > TCP window size: 256 KByte (WARNING: requested 512 KByte) > > ------------------------------------------------------------ > > [ 3] local 192.168.0.2 port 52968 connected with 192.168.0.3 port 5001 > > [ ID] Interval Transfer Bandwidth > > [ 3] 0.0-10.0 sec 438 MBytes 267 Mbits/sec > > > > > > iperf -c 192.168.0.3 -w 512k -l 512k > > ------------------------------------------------------------ > > Client connecting to 192.168.0.3, TCP port 5001 > > TCP window size: 256 KByte (WARNING: requested 512 KByte) > > ------------------------------------------------------------ > > [ 3] local 192.168.0.2 port 52995 connected with 192.168.0.3 port 5001 > > [ ID] Interval Transfer Bandwidth > > [ 3] 0.0-10.0 sec 602 MBytes 505 Mbits/sec > > > > Any ideas what this could be? I attach a dmesg output of my host. > > Thx. > > > > Ben > > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- Thomas Fjellstrom tfjellstrom@shaw.ca