Re: register_timer_hook use in arch/sh/oprofile

[Ingo Molnar]

* Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:

> On Wed, 2009-06-24 at 15:24 +0200, Ingo Molnar wrote:
> > 
> > [ And long-term analysis ('perf stat' type of runs) dont need IRQs 
> >   anyway - perfcounters reads outs the counts and summarizes them 
> >   across the measured workload. ]
> 
> If the counter width is less than 64 bits we do need to have some 
> interrupt to read them from before they cycle so we can accumulate 
> the deltas into a proper u64.

Yeah - but even that can be driven from some housekeeping hrtimer.

> But for proper 64 bit hardware counters there is indeed no need 
> for that.

Indeed - although they are rare.

	Ingo
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