Re: BFS vs. mainline scheduler benchmarks and measurements

From: Peter Zijlstra
Date: Wed Sep 09 2009 - 05:02:58 EST


On Wed, 2009-09-09 at 10:52 +0200, Mike Galbraith wrote:
> @@ -1502,7 +1502,8 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int sync)
> */
> if (sched_feat(LAST_BUDDY) && likely(se->on_rq && curr != rq->idle))
> set_last_buddy(se);
> - set_next_buddy(pse);
> + if (sched_feat(NEXT_BUDDY))
> + set_next_buddy(pse);
>
> /*
> * We can come here with TIF_NEED_RESCHED already set from new task

You might want to test stuff like sysbench again, iirc we went on a
cache-trashing rampage without buddies.

Our goal is not to excel at any one load but to not suck at any one
load.

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