Re: [patch] sched: fix/add missing update_rq_clock() calls

Ingo Molnar
2009-11-12T11:27:33Z

* Peter Zijlstra <peterz@infradead.org> wrote:

> On Thu, 2009-11-12 at 11:07 +0100, Mike Galbraith wrote:
> > sched: fix/add missing update_rq_clock() calls.
> >
> > kthread_bind(), migrate_task() and sched_fork were missing updates, and
> > try_to_wake_up() was updating after having already used the stale clock.
>
>
> I'm almost at the point where I think we should ditch rq->clock
> alltogether and simply call cpu_clock() directly when we need it. This
> trying to optimize and avoid calling it game has brought way too many
> head-aches.

It's not just about optimization - it's also accounting precision - we
want to handle the full act of schedule() at a single timestamp - not a
series of timestamps.

But ... we can get rid of it if it can be done sanely.

Ingo