From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [Qemu-devel] tap devices not receiving packets from a bridge Date: Thu, 16 May 2013 09:24:05 +0300 Message-ID: <20130516062405.GA26548@redhat.com> References: <20121123070211.GC22787@stefanha-thinkpad.hitronhub.home> <20121123110146.GC7051@redhat.com> <50FE5607.9020405@dlhnet.de> <20130123100312.GA8108@redhat.com> <5119E9DC.3000505@dlhnet.de> <1368541284.15129.317.camel@eboracum.office.bytemark.co.uk> <519249F6.3000900@dlhnet.de> <1368542949.15129.354.camel@eboracum.office.bytemark.co.uk> <1368615603.15129.1471.camel@eboracum.office.bytemark.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Peter Lieven , Stefan Hajnoczi , qemu-devel@nongnu.org, netdev@vger.kernel.org To: Nicholas Thomas Return-path: Received: from mx1.redhat.com ([209.132.183.28]:62555 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753958Ab3EPGZJ (ORCPT ); Thu, 16 May 2013 02:25:09 -0400 Content-Disposition: inline In-Reply-To: <1368615603.15129.1471.camel@eboracum.office.bytemark.co.uk> Sender: netdev-owner@vger.kernel.org List-ID: On Wed, May 15, 2013 at 12:00:03PM +0100, Nicholas Thomas wrote: > Hi again, > > On Tue, 2013-05-14 at 15:49 +0100, Nicholas Thomas wrote: > > /sys/devices/virtual/net/t100/tun_flags is 0x5002 - so it looks like > > IFF_ONE_QUEUE was indeed unset by qemu (which is lacking the patch). It > > surprises me, but that's probably my fault, rather than qemu's. > > > I've rebuilt 1.4.1 with the IFF_ONE_QUEUE patch and tun_flags is now > 0x7002; unfortunately, I'm still seeing this bug, twice in five trials. > Symptoms in `ifconfig t100` now differ; overruns stays at 0, and > "dropped" increases monotonically as I send packets. Those packets do > appear if I tcpdump t100 on the host, but not if I tcpdump t100 on the > guest. > > I've turned off gro in the guest, which makes no difference, and tried > changing the queue sizes (post-hoc) in both guest and host, in the hope > of causing them to be emptied out, clearing the condition; again to no > effect. > > The VMs in question are bridged to a large (and busy) VLAN with no > ingress filtering to speak of; I guess what's happening is that the > transmit queue is filled up by that traffic while the guest is in ipxe, > and it never gets out of that state when it happens... so maybe there is > still an underlying problem? > > /Nick Is this with or without vhost-net in host? -- MST