Re: [PATCH] sched,trace: Allow tracing the preemption decision on wakeup

[Paul Turner]

Yeah -- this one is a real no brainer to move; looks good :)

On Thu, Mar 14, 2013 at 5:00 AM, Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
> On Thu, 2013-03-14 at 10:48 +0100, Peter Zijlstra wrote:
>> Thomas noted that we do the wakeup preemption check after the wakeup
>> trace point, this means the tracepoint cannot test/report this decision;
>> which is rather important for latency sensitive workloads. Therefore
>> move the tracepoint after doing the preemption check.
>>
>> Suggested-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
>> Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
>
> Acked-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
>
>> ---
>>  kernel/sched/core.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
>> index b36635e..849deb9 100644
>> --- a/kernel/sched/core.c
>> +++ b/kernel/sched/core.c
>> @@ -1288,8 +1288,8 @@ static void ttwu_activate(struct rq *rq, struct task_struct *p, int en_flags)
>>  static void
>>  ttwu_do_wakeup(struct rq *rq, struct task_struct *p, int wake_flags)
>>  {
>> -     trace_sched_wakeup(p, true);
>>       check_preempt_curr(rq, p, wake_flags);
>> +     trace_sched_wakeup(p, true);
>>
>>       p->state = TASK_RUNNING;
>>  #ifdef CONFIG_SMP
>>
>
>
--
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/