From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bill Davidsen Subject: Re: [PATCH 0/9][RFC] KVM virtio_net performance Date: Sun, 27 Jul 2008 08:52:30 -0400 Message-ID: <488C6F8E.1020406@tmr.com> References: <1216899979-32532-1-git-send-email-markmc@redhat.com> <4888EC61.8050208@codemonkey.ws> <488B7668.7090605@tmr.com> <488C292C.7020609@qumranet.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Anthony Liguori , Mark McLoughlin , kvm@vger.kernel.org, Herbert Xu , Rusty Russell To: Avi Kivity Return-path: Received: from mail.tmr.com ([64.65.253.246]:40610 "EHLO gaimboi.tmr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751518AbYG0MuI (ORCPT ); Sun, 27 Jul 2008 08:50:08 -0400 In-Reply-To: <488C292C.7020609@qumranet.com> Sender: kvm-owner@vger.kernel.org List-ID: Avi Kivity wrote: > Bill Davidsen wrote: >> Anthony Liguori wrote: >>> Hi Mark, >>> >>> [...snip...] >>> I'm still seeing the same problem I saw with my patch series. >>> Namely, dhclient fails to get a DHCP address. Rusty noticed that RX >>> has a lot more packets received then it should so we're suspicious >>> that we're getting packet corruption. >> >> I have been discussing this (on this list) in another thread. Putting >> tcpdump on the eth0 device in the VM, the br0 device in the host, and >> the eth0 (physical NIC) in the host, you can see that when the VM >> generates a DHCP request it shows up on the br0 in the host, but >> never gets sent on the wire by eth0. >> >> That's the point of failure, at least using RHEL5/FC6/kvm-66 as the >> environment. > > Does playing with the bridge forward delay ('brctl setfd') help? > Not obviously, default value is 15, stepping from 10..30 made no difference. It appears the bridge just doesn't forward DHCP packets. I'm not an expert on bridge setup, and I don't see an obvious control, so I will look at the code this afternoon and see if something jumps out at me. -- Bill Davidsen "Woe unto the statesman who makes war without a reason that will still be valid when the war is over..." Otto von Bismark