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

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

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Chen Shang
2005-06-25 14:57:31 -07:00
committed by Linus Torvalds
parent 77391d7168
commit a3464a102a
1 changed files with 12 additions and 7 deletions
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15
kernel/sched.c
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@@ -673,7 +673,7 @@ static inline void __activate_idle_task(task_t *p, runqueue_t *rq)
rq->nr_running++; 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' */ /* Caller must always ensure 'now >= p->timestamp' */
unsigned long long __sleep_time = 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 #endif
recalc_task_prio(p, now); p->prio = recalc_task_prio(p, now);
/* /*
* This checks to make sure it's not an uninterruptible task * This checks to make sure it's not an uninterruptible task
@@ -2751,7 +2751,7 @@ asmlinkage void __sched schedule(void)
struct list_head *queue; struct list_head *queue;
unsigned long long now; unsigned long long now;
unsigned long run_time; unsigned long run_time;
int cpu, idx; int cpu, idx, new_prio;
/* /*
* Test if we are atomic. Since do_exit() needs to call into * 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; delta = delta * (ON_RUNQUEUE_WEIGHT * 128 / 100) / 128;
array = next->array; array = next->array;
new_prio = recalc_task_prio(next, next->timestamp + delta);
if (unlikely(next->prio != new_prio)) {
dequeue_task(next, array); dequeue_task(next, array);
recalc_task_prio(next, next->timestamp + delta); next->prio = new_prio;
enqueue_task(next, array); enqueue_task(next, array);
} else
requeue_task(next, array);
} }
next->activated = 0; next->activated = 0;
switch_tasks: switch_tasks: