much better.
If so, another place, activate_task(), need to make adjustment as well.
-chen
/* ============================ */
/*
@@ -704,7 +704,7 @@
}
#endif
- recalc_task_prio(p, now);
+ p->prio = recalc_task_prio(p, now);
/* ============================ */
On 5/23/05, Ingo Molnar <[email protected]> wrote:
>
> the real problem comes from recalc_task_prio() having a side-effect,
> which makes requeueing of tasks harder. The solution is to return the
> prio from recalc_task_prio() - see the tested patch below. Agreed?
>
> Ingo
>
> --
>
> micro-optimize task requeueing in schedule() & clean up
> recalc_task_prio().
>
> --- linux/kernel/sched.c.orig
> +++ linux/kernel/sched.c
> @@ -675,7 +675,7 @@ static inline void __activate_idle_task(
> rq->nr_running++;
> }
>
> -static void recalc_task_prio(task_t *p, unsigned long long now)
> +static int recalc_task_prio(task_t *p, unsigned long long now)
> {
> /* Caller must always ensure 'now >= p->timestamp' */
> unsigned long long __sleep_time = now - p->timestamp;
> @@ -734,7 +734,7 @@ static void recalc_task_prio(task_t *p,
> }
> }
>
> - p->prio = effective_prio(p);
> + return effective_prio(p);
> }
>
> /*
> @@ -757,7 +757,7 @@ static void activate_task(task_t *p, run
> }
> #endif
>
> - recalc_task_prio(p, now);
> + p->prio = recalc_task_prio(p, now);
>
> /*
> * This checks to make sure it's not an uninterruptible task
> @@ -2751,7 +2751,7 @@ asmlinkage void __sched schedule(void)
> struct list_head *queue;
> unsigned long long now;
> unsigned long run_time;
> - int cpu, idx;
> + int cpu, idx, new_prio;
>
> /*
> * Test if we are atomic. Since do_exit() needs to call into
> @@ -2873,9 +2873,14 @@ go_idle:
> delta = delta * (ON_RUNQUEUE_WEIGHT * 128 / 100) / 128;
>
> array = next->array;
> - dequeue_task(next, array);
> - recalc_task_prio(next, next->timestamp + delta);
> - enqueue_task(next, array);
> + new_prio = recalc_task_prio(next, next->timestamp + delta);
> +
> + if (unlikely(next->prio != new_prio)) {
> + dequeue_task(next, array);
> + next->prio = new_prio;
> + enqueue_task(next, array);
> + } else
> + requeue_task(next, array);
> }
> next->activated = 0;
> switch_tasks:
>
-
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