[PATCH v3 0/7] Add common cpuidle code for consolidation.

Kevin Hilman khilman at ti.com
Tue Jan 31 16:55:19 EST 2012


Rob Lee <rob.lee at linaro.org> writes:

> On Tue, Jan 24, 2012 at 2:08 PM, Kevin Hilman <khilman at ti.com> wrote:
>> I noticed that the generic code uses ktime_get() for measuring time.  On
>> OMAP, we use getnstimeofday() because I while back I remember having
>> problems with the interaction of CPUidle state measurements and system
>> suspend.  Any idle activity during system suspend/resume ktime_get()
>> will WARN() because the timekeeping system has been suspended.
>
> It seems that all the time keeping functions including
> getnstimeofday() now have the "WARN_ON(timekeeping_suspended)" or
> WARN_ON_ONCE.  So I'd like to stick with ktime_get unless I'm missing
> something about the suspend warning or unless there is some other
> reason why getnstieofday() is preferred.

I agree.  

I've convinced myself that my use of getnstimeofday() is because of a
problem that doesn't exist anymore in mainline, and now that the
timekeeping core has been converted to use syscore_ops, use of
ktime_get() is good.

Kevin




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