Re: NUMA scheduler broken

Martin J. Bligh (mbligh@aracnet.com)
Fri, 07 Mar 2003 08:24:02 -0800


>> Looks like __activate_task() should call nr_running_inc(rq) rather than
>> rq->nr_running++, and the same in wake_up_forked_process(). My guess is
>> that the bogus node_nr_running value is causing some really poor
>> scheduling decisions to be made on NUMA. See if that changes your
>> result.

Yay! that fixes it. Nice catch Rick.

> indeed. The attached patch (against BK-curr) fixes this.

Thanks Ingo ... Linus, could you add that one?

Thanks,

M.

> Ingo
>
> --- kernel/sched.c.orig 2003-03-07 13:40:53.000000000 +0100
> +++ kernel/sched.c 2003-03-07 13:41:19.000000000 +0100
> @@ -325,7 +325,7 @@
> static inline void __activate_task(task_t *p, runqueue_t *rq)
> {
> enqueue_task(p, rq->active);
> - rq->nr_running++;
> + nr_running_inc(rq);
> }
>
> static inline void activate_task(task_t *p, runqueue_t *rq)
> @@ -545,7 +545,7 @@
> list_add_tail(&p->run_list, &current->run_list);
> p->array = current->array;
> p->array->nr_active++;
> - rq->nr_running++;
> + nr_running_inc(rq);
> }
> task_rq_unlock(rq, &flags);
> }
>
>

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