Messages in this thread | | | Date | Wed, 25 May 2005 10:54:48 -0700 | From | George Anzinger <> | Subject | Re: 2.6.11 timeval_to_jiffies() wrong for ms resolution timers |
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Chris Friesen wrote: > George Anzinger wrote: > >> Bhavesh P. Davda wrote: >> >>> setitimer for 20ms was firing at 21ms > > >> If we do NOT account for this PIT issue, the result is a time drift >> that is outside of what ntp can handle... > > > Still, it is non-intuitive that a multi-GHz machine can't wake you up > more accurately than 1ms. > > What about telling it to wake up a jiffy earlier, then checking whether > the scheduling lag was enough to cause it to have waited the full > specified time. If not, put it to sleep for another jiffy.
The user is, of course, free to do what ever they would like. For a more complete solution you might be interested in HRT (High Res Timers). See my signature below. > -- George Anzinger george@mvista.com High-res-timers: http://sourceforge.net/projects/high-res-timers/ - 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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