Re: [PATCH 1/7] sched: Update rq clock on nohz CPU before migratingtasks

[Peter Zijlstra]

On Sat, 2013-04-06 at 18:45 +0200, Frederic Weisbecker wrote:
> Because the sched_class::put_prev_task() callback of rt and fair
> classes are referring to the rq clock to update their runtime
> statistics. A CPU running in tickless mode may carry a stale value.
> We need to update it there.

I'm failing to see how tickless makes a difference here.. we should
never rely on a ->clock set at the last tick, that's wrong.

So either explain which/how clock update gets lost by tickless or make
it unconditional.

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