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On 1/20/07, Arjan van de Ven <arjan@infradead.org> wrote: > On Sat, 2007-01-20 at 15:54 +0530, kalash nainwal wrote: > > Hi there, > > > > We've a kernel (n/w) module, which sits over ethernet. Whenever a pkt > > is received (in softirq), after doing some minimal processing, > > wake_up() is called to wake up another kernel thread which does rest > > (bulk) of the processing. > > > > We notice that this wake_up() call is sometimes taking as long as 48 > > milli-seconds to return. This happens around 10 times out of 10M. We > > earlier thought its possibly because of the contention on rq->lock, > > but we see the same phenomenon even on a uniprocessor box. So obviosly > > thats not the case. > > > > We can't figure out any other reason for wake_up() to take this much > > time? As this call comes directly in our (receive) hotpath, we're very > > concerned. Any help would be greatly appreciated. > > > Hi, > > unfortunately you didn't provide your driver code or a link to it, so > people who want to help you would have to guess in the dark... could you > reply to this email with the pointer to the code? > > Greetings, > Arjan van de Ven > -- > if you want to mail me at work (you don't), use arjan (at) linux.intel.com > Test the interaction between Linux and your BIOS via http://www.linuxfirmwarekit.org > > Hi Arjan, I won't pretend I'm working on an open-source driver. I personally would be more than happy to share the driver code, but doing so would probably cost me my job :) and so...I won't expect anyone to help me with my code either. Just wanted to know if wake_up is known to take this long to return? (some known linux quirk may be?) If so then under what conditions? or it _definitely_ would be my code only that's screwing up? I'm using do_gettimeofday() before and after wake_up() to measure this time. Thanks and regards, -Kalash - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | ||||||||||||
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