rtl8139 stop working under high load

rtl8139 stop working under high load

[Farkas Levente]

hi,
i'm just switch to the use rtl8139 network emulator in kvm-70 for the 
guests, but under high load it's simple stop working. a reboot or even a
service network restart
solve the problem, but imho there should have to be some bug in the 
qemu's rtl8139 code. and there is not any kind of error in any log 
(neither the host's nor the guest's).
this not happened with e1000. but with e1000 the network sometimes seems 
to breathing (sometimes slow down and then speed up again).
do currently which is the preferred network network device in qemu/kvm?
thanks.

-- 
   Levente                               "Si vis pacem para bellum!"

Re: rtl8139 stop working under high load

[Dor Laor]

Farkas Levente wrote:
> hi,
> i'm just switch to the use rtl8139 network emulator in kvm-70 for the 
> guests, but under high load it's simple stop working. a reboot or even a
> service network restart
> solve the problem, but imho there should have to be some bug in the 
> qemu's rtl8139 code. and there is not any kind of error in any log 
> (neither the host's nor the guest's).
> this not happened with e1000. but with e1000 the network sometimes 
> seems to breathing (sometimes slow down and then speed up again).
> do currently which is the preferred network network device in qemu/kvm?
> thanks.
>
I think rtl8139 is the most stable, and afterwards virtio and e1000 
(which both perform much better too).
Maybe it's irq problem. Can you run the same test with -no-kvm-irqchip ?

Re: rtl8139 stop working under high load

[Farkas Levente]

Dor Laor wrote:
> Farkas Levente wrote:
>> hi,
>> i'm just switch to the use rtl8139 network emulator in kvm-70 for the 
>> guests, but under high load it's simple stop working. a reboot or even a
>> service network restart
>> solve the problem, but imho there should have to be some bug in the 
>> qemu's rtl8139 code. and there is not any kind of error in any log 
>> (neither the host's nor the guest's).
>> this not happened with e1000. but with e1000 the network sometimes 
>> seems to breathing (sometimes slow down and then speed up again).
>> do currently which is the preferred network network device in qemu/kvm?
>> thanks.
>>
> I think rtl8139 is the most stable, and afterwards virtio and e1000 
> (which both perform much better too).
> Maybe it's irq problem. Can you run the same test with -no-kvm-irqchip ?

it happened when i run revisor to build iso through an nsf mounted 
volume (where the nefs server was another kvm guest). i try 4 times with 
rtl8139 and it always stop working. when i switch back to e1000 then 
this not happened.
i can't test it now remotely:-(

-- 
   Levente                               "Si vis pacem para bellum!"

Re: rtl8139 stop working under high load

[Avi Kivity]

Farkas Levente wrote:
> hi,
> i'm just switch to the use rtl8139 network emulator in kvm-70 for the 
> guests, but under high load it's simple stop working. a reboot or even a
> service network restart
> solve the problem, but imho there should have to be some bug in the 
> qemu's rtl8139 code. and there is not any kind of error in any log 
> (neither the host's nor the guest's).
> this not happened with e1000. but with e1000 the network sometimes 
> seems to breathing (sometimes slow down and then speed up again).
> do currently which is the preferred network network device in qemu/kvm?

kvm-71 contains a fix for ioapic interrupts under load, please test it 
when it comes out.


-- 
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