From: "Michael S. Tsirkin" <mst@redhat.com> To: Nicholas Thomas <nick@bytemark.co.uk> Cc: Peter Lieven <pl@dlhnet.de>, Stefan Hajnoczi <stefanha@gmail.com>, qemu-devel@nongnu.org, netdev@vger.kernel.org Subject: Re: [Qemu-devel] tap devices not receiving packets from a bridge Date: Thu, 16 May 2013 09:27:43 +0300 [thread overview] Message-ID: <20130516062743.GB26548@redhat.com> (raw) In-Reply-To: <20130516062405.GA26548@redhat.com> On Thu, May 16, 2013 at 09:24:05AM +0300, Michael S. Tsirkin wrote: > 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? never mind, I see it's without. Try to enable vhost-net (you'll have to switch to -netdev syntax for that to work) and see if this help. If it does it's likely a qemu bug if not probably a guest bug. > -- > MST
WARNING: multiple messages have this Message-ID (diff)
From: "Michael S. Tsirkin" <mst@redhat.com> To: Nicholas Thomas <nick@bytemark.co.uk> Cc: Stefan Hajnoczi <stefanha@gmail.com>, Peter Lieven <pl@dlhnet.de>, qemu-devel@nongnu.org, netdev@vger.kernel.org Subject: Re: [Qemu-devel] tap devices not receiving packets from a bridge Date: Thu, 16 May 2013 09:27:43 +0300 [thread overview] Message-ID: <20130516062743.GB26548@redhat.com> (raw) In-Reply-To: <20130516062405.GA26548@redhat.com> On Thu, May 16, 2013 at 09:24:05AM +0300, Michael S. Tsirkin wrote: > 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? never mind, I see it's without. Try to enable vhost-net (you'll have to switch to -netdev syntax for that to work) and see if this help. If it does it's likely a qemu bug if not probably a guest bug. > -- > MST
next prev parent reply other threads:[~2013-05-16 6:27 UTC|newest] Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top 2012-11-22 14:29 tap devices not receiving packets from a bridge Peter Lieven 2012-11-22 14:29 ` [Qemu-devel] " Peter Lieven 2012-11-23 7:02 ` Stefan Hajnoczi 2012-11-23 7:02 ` Stefan Hajnoczi 2012-11-23 9:41 ` Peter Lieven 2012-11-23 9:41 ` Peter Lieven 2012-11-23 11:01 ` Michael S. Tsirkin 2012-11-23 11:02 ` Peter Lieven 2012-11-23 11:02 ` Peter Lieven 2013-01-22 9:04 ` Peter Lieven 2013-01-22 9:43 ` Peter Lieven 2013-01-23 10:03 ` [Qemu-devel] " Michael S. Tsirkin 2013-02-12 7:06 ` Peter Lieven 2013-02-12 9:08 ` [Qemu-devel] " Michael S. Tsirkin 2013-02-12 9:10 ` Peter Lieven 2013-02-12 9:29 ` Michael S. Tsirkin 2013-02-12 9:39 ` Michael Tokarev 2013-02-12 9:54 ` Michael S. Tsirkin 2013-02-12 10:11 ` [Qemu-devel] " Peter Lieven 2013-02-12 10:43 ` Michael S. Tsirkin 2013-05-14 14:21 ` Nicholas Thomas 2013-05-14 14:21 ` [Qemu-devel] " Nicholas Thomas 2013-05-14 14:28 ` Peter Lieven 2013-05-14 14:28 ` [Qemu-devel] " Peter Lieven 2013-05-14 14:49 ` Nicholas Thomas 2013-05-14 14:49 ` [Qemu-devel] " Nicholas Thomas 2013-05-15 11:00 ` Nicholas Thomas 2013-05-15 11:00 ` Nicholas Thomas 2013-05-16 6:24 ` Michael S. Tsirkin 2013-05-16 6:24 ` Michael S. Tsirkin 2013-05-16 6:27 ` Michael S. Tsirkin [this message] 2013-05-16 6:27 ` Michael S. Tsirkin 2013-05-16 8:20 ` Nicholas Thomas 2013-05-16 8:20 ` Nicholas Thomas 2013-05-16 8:40 ` Michael S. Tsirkin 2013-05-16 8:40 ` Michael S. Tsirkin 2013-05-16 8:47 ` Peter Lieven 2013-05-16 8:47 ` Peter Lieven 2013-05-16 11:27 ` Nicholas Thomas 2013-05-16 11:27 ` Nicholas Thomas 2013-05-16 12:09 ` Michael S. Tsirkin 2013-05-16 12:09 ` Michael S. Tsirkin 2012-11-29 18:58 ` Peter Lieven 2012-11-29 18:58 ` Peter Lieven
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