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SubjectRe: [PATCH 3/7] sched: Update rq clock on tickless CPUs before calling check_preempt_curr()
From
2013/4/9 Peter Zijlstra <peterz@infradead.org>:
> On Sat, 2013-04-06 at 18:45 +0200, Frederic Weisbecker wrote:
>> check_preempt_wakeup() of fair class needs an uptodate sched clock
>> value to update runtime stats of the current task.
>>
>> When a task is woken up, activate_task() is usually called right
>> before
>> ttwu_do_wakeup() unless the task is still in the runqueue. In this
>> case we need to update the rq clock manually in case the CPU runs
>> tickless because ttwu_do_wakeup() calls check_preempt_wakeup().
>
> again, same story.. I think the entire nohz specific clock update stuff
> is completely broken and you're finding sites that are simply missing
> clock updates.
>

Agreed!


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