Re: [RFC/PATCH] sched: Honor sync wake up in select_idle_sibling

[Namhyung Kim]

Hi, Mike

On Fri, 10 Aug 2012 10:14:44 +0200, Mike Galbraith wrote:
> On Fri, 2012-08-10 at 16:25 +0900, Namhyung Kim wrote: 
>> From: Namhyung Kim <namhyung.kim@xxxxxxx>
>> 
>> When sync wakeup happens and there's the waker task running alone,
>> select the target cpu as if it's already idle.
>
> Ouch.  That defeats the purpose of select_idle_sibling().  Just because
> we're doing a sync wakeup does not mean there's no convertible overlap,
> nor that the waker is really really going to take a nap immediately.  A
> lot of the places that benefit up to and including hugely from looking
> for an idle shared cache to wake to do sync wakeups.

Thanks for the explanation! I misunderstood the function ;)

Thanks,
Namhyung

--
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/