Re: register_timer_hook use in arch/sh/oprofile

[Peter Zijlstra <peterz@infradead.org>]

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.

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