Re: [PATCH v4 0/6] sched: use runnable load based balance

From: Alex Shi
Date: Fri May 03 2013 - 03:56:36 EST



> That should probably look like:
>
> preempt_disable();
> raw_spin_unlock_irq();
> preempt_enable_no_resched();
> schedule();
>
> Otherwise you might find a performance regression on PREEMPT=y kernels.

Yes, right!
Thanks a lot for reminder. The following patch will fix it.
>
> OK, so what I was asking after is if you changed the scheduler after PJTs
> patches landed to deal with this bulk wakeup. Also while aim7 might no longer
> trigger the bad pattern what is to say nothing ever will? In particular
> anything using pthread_cond_broadcast() is known to be suspect of bulk wakeups.

Just find a benchmark named as pthread_cond_broadcast.
http://kristiannielsen.livejournal.com/13577.html. will play with it. :)
>
> Anyway, I'll go try and make sense of some of the actual patches.. :-)
>

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