Re: [patch] sched: align rq to cacheline boundary

From: Ingo Molnar
Date: Tue Apr 10 2007 - 02:25:08 EST



* Siddha, Suresh B <suresh.b.siddha@xxxxxxxxx> wrote:

> Align the per cpu runqueue to the cacheline boundary. This will
> minimize the number of cachelines touched during remote wakeup.

> -static DEFINE_PER_CPU(struct rq, runqueues);
> +static DEFINE_PER_CPU(struct rq, runqueues) ____cacheline_aligned_in_smp;

ouch!! Now how did _that_ slip through. The runqueues had been
cacheline-aligned for ages. Or at least, they were supposed to be.

could you see any improvement in profiles or workloads with this patch
applied? (just curious - it's an obviously right fix)

> Signed-off-by: Suresh Siddha <suresh.b.siddha@xxxxxxxxx>

Acked-by: Ingo Molnar <mingo@xxxxxxx>

Ingo
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