Re: [RFC GIT PULL] sched; Fix a few missing rq clock updates

From: Peter Zijlstra
Date: Tue May 14 2013 - 07:59:24 EST


On Fri, Apr 12, 2013 at 01:50:57AM +0200, Frederic Weisbecker wrote:
> Hi,
>
> So I revisited the rq clock series I had for dynticks. The patches
> actually were about upstream issues so I refactored the fixes
> under that angle and gave up with the wrong asumption that rq
> clock relies on the tick for its updates.
>
> Patches 1-4 fix some missing updates. Additionally I removed
> 2 of these updates from the previous set:
>
> * No need to update the rq clock on idle_balance() because it should
> follow a call to deactivate_task() (unless TIF_NEED_RESCHED is set
> on idle without new task on the runqueue, not sure we want to cover that).
>
> * No need to update for try_to_wake_up_local() -> ttwu_do_wakeup() -> check_preempt_curr()
> as it's following deactivate_task().
>
> Patch 5 brings accessors that will be necessary to settle an rq clock
> debugging engine. What remains is to tag scheduler's entry/exit points
> and report missing or redundant update_rq_clock() before calls to
> rq_clock() and rq_clock_task().

Just noticed this queue was still sitting in the INBOX, I took it and will
soon-ish hand to Ingo.

Thanks!
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