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

[Frederic Weisbecker]

2013/4/9 Peter Zijlstra <peterz@xxxxxxxxxxxxx>:
> 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.

Ah I made that big mis-assumption then ;)

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

So most of those fixup need to be made unconditional I think.
--
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/