Re: [PATCH] hrtimer: increase clock min delta threshold whileinterrupt hanging

From: Ingo Molnar
Date: Mon Dec 22 2008 - 04:06:12 EST



* Frédéric Weisbecker <fweisbec@xxxxxxxxx> 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
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