From: Peter Lieven <lieven-lists@dlhnet.de>
To: Stefan Hajnoczi <stefanha@redhat.com>
Cc: oliver.francke@filoo.de, qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH] rtl8139: flush queued packets when RxBufPtr is written
Date: Mon, 27 May 2013 12:19:16 +0200 [thread overview]
Message-ID: <51A33324.6050902@dlhnet.de> (raw)
In-Reply-To: <20130527083225.GA21969@stefanha-thinkpad.redhat.com>
On 27.05.2013 10:32, Stefan Hajnoczi wrote:
> On Mon, May 27, 2013 at 08:15:42AM +0200, Peter Lieven wrote:
>> I ocassionally have seen a probably related problem in the past. It mainly happend with rtl8139 under
>> WinXP where we most likely use rtl8139 due to lack of shipped e1000 drivers.
>>
>> My question is if you see increasing dropped packets on the tap device if this problem occurs?
>>
>> tap36 Link encap:Ethernet HWaddr b2:84:23:c0:e2:c0
>> inet6 addr: fe80::b084:23ff:fec0:e2c0/64 Scope:Link
>> UP BROADCAST RUNNING PROMISC MULTICAST MTU:1500 Metric:1
>> RX packets:5816096 errors:0 dropped:0 overruns:0 frame:0
>> TX packets:3878744 errors:0 dropped:13775 overruns:0 carrier:0
>> collisions:0 txqueuelen:500
>> RX bytes:5161769434 (5.1 GB) TX bytes:380415916 (380.4 MB)
> My reading of the tun code is that will see TX dropped increase. This
> is because tun keeps a finite size queue of tx packets. Since QEMU
> userspace is not monitoring the tap fd anymore we'll never drain the
> queue and soon enough the TX dropped counter will begin incrementing.
Ok, so this would fit.
>
>> In my case as well the only option to recover without shutting down the whole vServer is Live Migration
>> to another Node.
>>
>> However, I also see this problem under qemu-kvm-1.2.0 while Oliver reported it does not happen there.
> Yes, the patch that exposes this problem was only merged in 1.2.1.
Can you say which patch exactly? I cherry-picked some patches by hand.
>
> Can you still reproduce the problem now that the patch has been merged
> into qemu.git/master?
Unfortunately, I have no reliable way of reproducing the issue. It only happens
from time to time.
Peter
next prev parent reply other threads:[~2013-05-27 10:19 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-22 12:50 [Qemu-devel] [PATCH] rtl8139: flush queued packets when RxBufPtr is written Stefan Hajnoczi
2013-05-22 12:53 ` Andreas Färber
2013-05-22 13:33 ` Stefan Hajnoczi
2013-05-24 14:34 ` Stefan Hajnoczi
2013-05-27 6:15 ` Peter Lieven
2013-05-27 8:32 ` Stefan Hajnoczi
2013-05-27 10:19 ` Peter Lieven [this message]
2013-05-27 14:07 ` Oliver Francke
2013-05-27 14:24 ` Peter Lieven
2013-05-27 15:29 ` Stefan Hajnoczi
2013-05-28 6:27 ` Peter Lieven
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