Re: 2.6.6 e1000 NETDEV WATCHDOG: eth0: transmit timed out+ delay scheduler

[Jens Laas <jens.laas@xxxxxxxxxxx>]

(04.06.18 kl.10:08) David Greaves skrev följande till Jens Laas:

> Stephen, I applied your delay scheduler patch and some results appear below.
>
> Jens Laas wrote:
>
> > (04.06.16 kl.11:59) David Greaves skrev följande till Stephen Hemminger:
> >
> > We have seen the same symptoms. (2.6.x + e1000)
> >
> > Our system is an SMP system. That might be whats triggering the problem.
> > Is your system UP or SMP ?
>
> UP

Ok. This keeps getting stranger..


> > (Next reboot we will test running on only one CPU).
> >
> > We have tried with and without NAPI, both exhibit the same problem.
>
> Me too
>
> > We have tried different versions of e1000 without luck.
...
> > Make sure that flowcontrol is disabled on your switch (if it has it 
> > implemented).
>
> ...so it's not that smart anymore ;)
>
> > > module parameters.
> >
> >
> > I believe following is recommended by driver developers:
> > TxDescriptors=256 RxDescriptors=256 FlowControl=0 XsumRX=0
>
> Yes, I'm running with module defaults unless otherwise stated but I've tried 
> that combo (to no effect)

No effect here either. FlowControl and XsumRX are known troublemakers.

> I'm speaking with Ganesh Venkatesan at intel about it. Ganesh you went off 
> list - do you want to include Jens or maybe go back on-list?

If others run into this problem I'm sure they'll appreciate if its on 
list.
Since we have no idea what causes this (AFAIK) it may be a more general 
problem than the device driver.

> A simple failure case for me is : 'ping -s 1500 '
> This doesn't cause the timout but doesn't succeed either.
>
> ping -f with standard packet size succeeds (slow rate though) and doesn't 
> timeout.

I dont see the ping problems at all. Unless you try to ping when the 
interface has "hanged" ?


> Using 8139 100Mbs card:
> 272384 packets transmitted, 272383 packets received, 0% packet loss
> round-trip min/avg/max = 0.1/0.1/4.0 ms
> real    0m32.179s
>
> Using Pro/1000:
> 60992 packets transmitted, 60991 packets received, 0% packet loss
> round-trip min/avg/max = 0.0/0.5/8.4 ms
> real    0m38.257s
>
> any ping with -s >1500 results in 100% packet loss.
>
> ============
> From hereon down it's 2.6.7 with Stephen's recent delay scheduler patch
>
> This changed the behaviour.

This is strange unless you are actually using the delay scheduler ?
Default is sch_generic (that is pfifo) that does not exhibit the problems 
correct by the patch.


> 10592 packets transmitted, 10591 packets received, 0% packet loss
> round-trip min/avg/max = 5.4/5.5/83.5 ms
>
> Increasing Transmit Descriptors to 4096 avoids the No buffer space available 
> with packet sizes up to -s65468 (still 100% failure though)

Increasing nr of buffers is not a way to fix the problem.

I had hoped to hear something about this from Scott..

Cheers,
Jens

> I'm not sure that adds much now so I'll leave it until I get some more 
> suggestions.
>
> HTH
>
> David

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