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

[Peter Zijlstra]

On Thu, 2009-11-12 at 12:27 +0100, Ingo Molnar wrote:
> * Peter Zijlstra <peterz@xxxxxxxxxxxxx> 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.

Ah, good point, hard to do for the migration paths though.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/