Re: [PATCH 2/8] cputime: Librarize per nsecs resolution cputime definitions

From: Frederic Weisbecker
Date: Wed Feb 20 2013 - 11:07:24 EST

2013/2/14 Kevin Hilman <khilman@xxxxxxxxxx>:
> Frederic Weisbecker <fweisbec@xxxxxxxxx> writes:
>> The full dynticks cputime accounting that we'll soon introduce
>> will rely on sched_clock(). And its clock can have a per
>> nanosecond granularity.
>> To prepare for this, we need to have a cputime_t implementation
>> that has this precision.
>> ia64 virtual cputime accounting already uses that granularity
>> so all we need is to librarize its implementation in the asm
>> generic headers.
> ...except that for it to be truly generic (i.e. usable on 32-bit arches),
> it should be using do_div() for 64-bit divides.
> I understand this series is targetted at 64-bit platforms currently, but
> I'm looking (again) at getting adaptive NOHZ working on ARM, and this
> was the first obvious obstacle to even compiling.
> I see this is already merged into tip/sched/core, so below is a patch on
> top of that to convert to using do_div(). If you're OK with the
> approach, I'll post it formally to LKML.

Yes please, this looks like something we want.

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