Re: [PATCH 3/7] sched: Update rq clock on tickless CPUs beforecalling check_preempt_curr()

[Frederic Weisbecker]

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