call for bge(4) testers

Wilkinson, Alex alex.wilkinson at
Thu Aug 24 00:18:32 UTC 2006

    0n Wed, Aug 23, 2006 at 02:04:20PM +0400, Gleb Smirnoff wrote: 

    >On Wed, Aug 23, 2006 at 06:55:04PM +0900, Pyun YongHyeon wrote:
    >P> On Wed, Aug 23, 2006 at 01:37:41PM +0400, Gleb Smirnoff wrote:
    >P>  > On Tue, Aug 22, 2006 at 01:20:23PM +0900, Pyun YongHyeon wrote:
    >P>  > P> After fixing em(4) watchdog bug, I looked over bge(4) and I think
    >P>  > P> bge(4) may suffer from the same issue. So if you have seen occasional
    >P>  > P> watchdog timeout errors on bge(4) please give the attached patch a try.
    >P>  > P> The patch does fix false watchdog timeout error only.
    >P>  > P> Typical pheonoma for false watchdog timeout error are
    >P>  > P>        o polling(4) fix the issue
    >P>  > P>        o random watchdog error
    >P>  > P> 
    >P>  > P> If my patch fix the issue you could see the following messages.
    >P>  > P> "missing Tx completion interrupt!" or "link lost -- resetting"
    >P>  > 
    >P>  > I still think that this fix is incorrect. It is just a more gentle
    >P>  > recovery from a fake watchdog timeout.
    >P> Its sole purpose is to reinitialize hardware for real watchdog
    >P> timeouts. It's not fix for general watchdog timeouts. As I said other
    >P> mails, the fake watchdog timeout(losing Tx interrupts) for hardwares
    >P> with Tx interrupt moderation capability could be normal thing. So I
    >P> just want to know bge(4) also has the same feature(bug).
    >According to several emails about em(4) fake watchdog timeouts, the
    >problem can be fixed by setting debug.mpsafenet=0. This makes me think
    >that the problem isn't caused by TX interrupt moderation, but some race
    >in the kernel. Really, if_slowtimo() doesn't acquire driver lock before
    >checking and modifying the if_timer field.
    >Afaik, NIC drivers that can do interrupt moderation should set a timer
    >to a sane value, based on interrupt moderation settings, so that the
    >watchdog won't be ever called fakely.

What is interrupt moderation ?


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