Re: sched_clock() uses are broken

Andi Kleen
2006-05-03T07:40:50Z

On Wednesday 03 May 2006 09:09, Mike Galbraith wrote:

> Given that most people are going to end up using the pm_timer anyway, I
> don't see the point of even having a sched_clock(). If it's jiffy
> resolution, it's useless. If it's wildly inaccurate (as it is in the
> SMP case, monotonicity issues aside) it's more than useless.

For sched_clock TSC is always used and it's fine - sched_clock
doesn't require the guarantees that make TSC often useless otherwise

e.g. the scheduler is designed to only use it on one CPU
and can also tolerate variations scaling with frequency.

-Andi