Messages in this thread | | | Date | Mon, 22 Dec 2008 10:24:51 +0100 | From | "Frédéric Weisbecker" <> | Subject | Re: [PATCH] hrtimer: increase clock min delta threshold while interrupt hanging |
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2008/12/22 Ingo Molnar <mingo@elte.hu>: > > * Frédéric Weisbecker <fweisbec@gmail.com> wrote: > >> > Also, there's min_delta doubling in tick_dev_program_event() itself >> > too - that interacts with the irq-overload logic: >> > >> > + dev->min_delta_ns = (unsigned long)try_time.tv64 * 3; >> > >> > Ingo >> >> That's what I explained above, the doubling of min delta in >> tick_dev_program_event() is never reached in my case. And moreover I'm >> not sure it is ever reached whatever the call sites of >> tick_dev_program_event() unless min delta has a very low value... > > yeah, that looks all rather messy and probably ineffective. Thomas, mind > to take a look? > > Frederic's patch solves a real timer-irq-overload extreme situation so i > find it rather valuable. Maybe we should do Frederic's patch as-is, have > the 'softer' min_delta behavior for the usual hrtimer codepaths - and the > more agressive one for the timer tick only? > > Ingo >
Oh a little thing. I wonder if 5 iterations to notice a hang is not too low for embedded systems on certain situations.... Since embedded systems could need high resolution timers for real time....
Actually perhaps 10 iterations would be more reasonable.... -- 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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