Commit a3464a10 authored by Chen Shang's avatar Chen Shang Committed by Linus Torvalds
Browse files

[PATCH] sched: micro-optimize task requeueing in schedule() 



micro-optimize task requeueing in schedule() & clean up recalc_task_prio().

Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 77391d71

kernel/sched.c

+12 −7
Original line number Diff line number Diff line
@@ -673,7 +673,7 @@ static inline void __activate_idle_task(task_t *p, runqueue_t *rq) 
	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;
@@ -732,7 +732,7 @@ static void recalc_task_prio(task_t *p, unsigned long long now) 
		}

	}



	p->prio = effective_prio(p);

	return effective_prio(p);

}



/*
@@ -755,7 +755,7 @@ static void activate_task(task_t *p, runqueue_t *rq, int local) 
	}

#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 @@ asmlinkage void __sched schedule(void) 
			delta = delta * (ON_RUNQUEUE_WEIGHT * 128 / 100) / 128;



		array = next->array;

		new_prio = recalc_task_prio(next, next->timestamp + delta);



		if (unlikely(next->prio != new_prio)) {

			dequeue_task(next, array);

		recalc_task_prio(next, next->timestamp + delta);

			next->prio = new_prio;

			enqueue_task(next, array);

		} else

			requeue_task(next, array);

	}

	next->activated = 0;

switch_tasks: