Kok, Auke wrote: > Max Krasnyansky wrote: >> Kok, Auke wrote: >>> Max Krasnyansky wrote: >>>> Kok, Auke wrote: >>>>> Max Krasnyansky wrote: >>>>>> So you don't think it's related to the interrupt coalescing by any >>>>>> chance ? >>>>>> I'd suggest to try and disable the coalescing and see if it makes any >>>>>> difference. >>>>>> We've had lots of issues with coalescing misbehavior. Not this bad (ie 1 >>>>>> second) though. >>>>>> >>>>>> Add this to modprobe.conf and reload e1000 module >>>>>> >>>>>> options e1000 RxIntDelay=0,0 RxAbsIntDelay=0,0 InterruptThrottleRate=0,0 >>>>>> TxIntDelay=0,0 TxAbsIntDelay=0,0 >>>>> that can't be the problem. irq moderation would only account for 2-3ms >>>>> variance >>>>> maximum. >>>> Oh, I've definitely seen worse than that. Not as bad as a 1second though. >>>> Plus you're talking >>>> about the case when coalescing logic is working as designed ;-). What if >>>> there is some kind of >>>> bug where timer did not expire or something. >>> we don't use a software timer in e1000 irq coalescing/moderation, it's all >>> in >>> hardware, so we don't have that problem at all. And I certainly have never >>> seen >>> anything you are referring to with e1000 hardware, and I do not know of any >>> bug >>> related to this. >>> >>> are you maybe confused with other hardware ? >>> >>> feel free to demonstrate an example... >> Just to give you a background. I wrote and maintain http://libe1000.sf.net >> So I know E1000 HW and SW in and out. > > wow, even I do not dare to say that! Ok maybe that was a bit of an overstatement :).
>> And no I'm not confused with other HW and I know that we're >> not using SW timers for the coalescing. HW can be buggy as well. Note that >> I'm not saying that I >> know for sure that the problem is coalescing, I'm just suggesting to take it >> out of the equation >> while Pavel is investigating. >> >> Unfortunately I cannot demonstrate an example but I've seen unexplained >> packet delays in the range >> of 1-20 milliseconds on E1000 HW (and boy ... I do have a lot of it in my >> labs). Once coalescing >> was disabled those problems have gone away. > > this sounds like you have some sort of PCI POST-ing problem and those can > indeed > be worse if you use any form of interrupt coalescing. In any case that is > largely > irrelevant to the in-kernel drivers, and as I said we definately have no open > issues on that right now, and I really do not recollect any as well either > (other > than the issue of interference when both ends are irq coalescing) I was actually talking about in kernel drivers. ie We were seeing delays with TIPC running over in kernel E1000 driver. And no it was not a TIPC issue, everything worked fine with over TG3 and issues went away when coalescing was disabled. Anyway, I think we can drop this subject. Max -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/