Re: [RFC][PATCH] Dynamic Tick: Allow 32-bit machines to sleep formore than 2.15 seconds

From: john stultz
Date: Tue Apr 21 2009 - 16:32:36 EST


On Tue, 2009-04-21 at 08:35 +0200, Ingo Molnar wrote:
> * Jon Hunter <jon-hunter@xxxxxx> wrote:
> > Anyway, making this change has allowed my 32-bit machine to sleep
> > for longer than ~2.15 seconds and thought this could be of
> > interest to others. Your comments/feedback would be appreciated.
> >
> Looks like a good thing at first sight. Thomas, John, what do you
> think?

The concern is many clocksources wrap after a handful of seconds. The
acpi_pm is the best example (its only 24 bits wide).

I brought this issue up earlier, and provided some example code that
could be used to limit the idle time appropriately for the current
clocksource here:

http://lkml.indiana.edu/hypermail/linux/kernel/0901.3/02693.html

Jon: Did you see that mail, or is there a reason you didn't adapt this
code into your patch?


thanks
-john


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