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SubjectRe: [RFC][PATCH] Dynamic Tick: Allow 32-bit machines to sleep for more than 2.15 seconds
On Tue, 2009-04-21 at 18:20 -0500, Jon Hunter wrote:
> john stultz wrote:
> > 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:
> >
> >
> >
> > Jon: Did you see that mail, or is there a reason you didn't adapt this
> > code into your patch?
> Hi John, yes I did read this email and thanks for bringing this up.
> As I looked at this more I noticed that for 64-bit machines that the
> max_delta_ns would be a 64-bit integer already and so this change would
> only have an impact for 32-bit machines. I understand that there are
> more 32-bit machines that 64-bit. However, I was trying to understand
> how the wrapping of clocksources, such as the one you mention above, is
> handled today for 64-bit machines that could theoretically sleep for
> longer periods.

One other minor comment nit, if we're really meaning that max_delta_ns
is a 64bit value, should we not just be using s64 and be explicit
instead of converting longs to long longs?


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