Re: Stolen and degraded time and schedulers

Daniel Walker
2007-03-14T20:34:06Z

On Wed, 2007-03-14 at 12:44 -0700, Jeremy Fitzhardinge wrote:
> Daniel Walker wrote:
> > sched_clock is used to bank real time against some specific states
> > inside the scheduler, and no it doesn't _just_ measure a processes
> > executing time.
> >
>
> Could you point these places out? All uses of sched_clock() that I
> could see in kernel/sched.c seemed to be related to working out how
> long
> something spent executing, either in the scheduler proper, or
> benchmarking cache characteristics.

For interactive tasks (basic scheduling) the execution time, and sleep
time need to be measured. It's also used for some posix cpu timers
(sched_ns) , and it used for migration thread initialization. I'm sure
it's used for a variety of out-of-tree random timing as well..

Daniel