Re: network shutdown under heavy load

[Tom Lendacky <tahm@linux.vnet.ibm.com>]

On Sunday 10 January 2010 06:38:54 am Avi Kivity wrote:
> On 01/10/2010 02:35 PM, Herbert Xu wrote:
> > On Sun, Jan 10, 2010 at 02:30:12PM +0200, Avi Kivity wrote:
> >> This isn't in 2.6.27.y.  Herbert, can you send it there?
> >
> > It appears that now that TX is fixed we have a similar problem
> > with RX.  Once I figure that one out I'll send them together.
> 

I've been experiencing the network shutdown issue also.  I've been running 
netperf tests across 10GbE adapters with Qemu 0.12.1.2, RHEL5.4 guests and 
2.6.32 kernel (from kvm.git) guests.  I instrumented Qemu to print out some 
network statistics.  It appears that at some point in the netperf test the 
receiving guest ends up having the 10GbE device "receive_disabled" variable in 
its VLANClientState structure stuck at 1.  From looking at the code it appears 
that the virtio-net driver in the guest should cause qemu_flush_queued_packets 
in net.c to eventually run and clear the "receive_disabled" variable but it's 
not happening.  I don't seem to have these issues when I have a lot of debug 
settings active in the guest kernel which results in very low/poor network 
performance - maybe some kind of race condition?

Tom

> Thanks.
> 
> > Who is maintaining that BTW, stable@kernel.org?
> 
> Yes.
>