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! > 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) Cheers, Auke -- 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/
