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authorLinus Torvalds <torvalds@woody.linux-foundation.org>2007-08-31 10:52:00 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-08-31 10:52:00 -0700
commit5e7a39275b00ec881790ce47b8f7363fdfa097fa (patch)
tree89f8bbefe362f11c23ea47163f3f01f1035cccf5 /kernel
parent7d9ef601ddf0a42d11df3bdaaf28078fd2995eab (diff)
parent9f508f8258e18e9333f18daf1f0860df48d49ed2 (diff)
downloadlinux-linaro-5e7a39275b00ec881790ce47b8f7363fdfa097fa.tar.gz
Merge git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-sched
* git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-sched: sched: clean up task_new_fair() sched: small schedstat fix sched: fix wait_start_fair condition in update_stats_wait_end() sched: call update_curr() in task_tick_fair() sched: make the scheduler converge to the ideal latency sched: fix sleeper bonus limit
Diffstat (limited to 'kernel')
-rw-r--r--kernel/sched.c1
-rw-r--r--kernel/sched_fair.c46
2 files changed, 36 insertions, 11 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index 9fe473a190d..b533d6db78a 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -1587,6 +1587,7 @@ static void __sched_fork(struct task_struct *p)
p->se.wait_start_fair = 0;
p->se.exec_start = 0;
p->se.sum_exec_runtime = 0;
+ p->se.prev_sum_exec_runtime = 0;
p->se.delta_exec = 0;
p->se.delta_fair_run = 0;
p->se.delta_fair_sleep = 0;
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index ee3771850aa..ce39282d9c0 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -354,7 +354,7 @@ __update_curr(struct cfs_rq *cfs_rq, struct sched_entity *curr)
delta_fair = calc_delta_fair(delta_exec, lw);
delta_mine = calc_delta_mine(delta_exec, curr->load.weight, lw);
- if (cfs_rq->sleeper_bonus > sysctl_sched_latency) {
+ if (cfs_rq->sleeper_bonus > sysctl_sched_min_granularity) {
delta = min((u64)delta_mine, cfs_rq->sleeper_bonus);
delta = min(delta, (unsigned long)(
(long)sysctl_sched_runtime_limit - curr->wait_runtime));
@@ -489,6 +489,9 @@ update_stats_wait_end(struct cfs_rq *cfs_rq, struct sched_entity *se)
{
unsigned long delta_fair;
+ if (unlikely(!se->wait_start_fair))
+ return;
+
delta_fair = (unsigned long)min((u64)(2*sysctl_sched_runtime_limit),
(u64)(cfs_rq->fair_clock - se->wait_start_fair));
@@ -668,7 +671,7 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int sleep)
/*
* Preempt the current task with a newly woken task if needed:
*/
-static void
+static int
__check_preempt_curr_fair(struct cfs_rq *cfs_rq, struct sched_entity *se,
struct sched_entity *curr, unsigned long granularity)
{
@@ -679,8 +682,11 @@ __check_preempt_curr_fair(struct cfs_rq *cfs_rq, struct sched_entity *se,
* preempt the current task unless the best task has
* a larger than sched_granularity fairness advantage:
*/
- if (__delta > niced_granularity(curr, granularity))
+ if (__delta > niced_granularity(curr, granularity)) {
resched_task(rq_of(cfs_rq)->curr);
+ return 1;
+ }
+ return 0;
}
static inline void
@@ -725,6 +731,7 @@ static void put_prev_entity(struct cfs_rq *cfs_rq, struct sched_entity *prev)
static void entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr)
{
+ unsigned long gran, ideal_runtime, delta_exec;
struct sched_entity *next;
/*
@@ -741,8 +748,22 @@ static void entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr)
if (next == curr)
return;
- __check_preempt_curr_fair(cfs_rq, next, curr,
- sched_granularity(cfs_rq));
+ gran = sched_granularity(cfs_rq);
+ ideal_runtime = niced_granularity(curr,
+ max(sysctl_sched_latency / cfs_rq->nr_running,
+ (unsigned long)sysctl_sched_min_granularity));
+ /*
+ * If we executed more than what the latency constraint suggests,
+ * reduce the rescheduling granularity. This way the total latency
+ * of how much a task is not scheduled converges to
+ * sysctl_sched_latency:
+ */
+ delta_exec = curr->sum_exec_runtime - curr->prev_sum_exec_runtime;
+ if (delta_exec > ideal_runtime)
+ gran = 0;
+
+ if (__check_preempt_curr_fair(cfs_rq, next, curr, gran))
+ curr->prev_sum_exec_runtime = curr->sum_exec_runtime;
}
/**************************************************
@@ -1076,31 +1097,34 @@ static void task_tick_fair(struct rq *rq, struct task_struct *curr)
static void task_new_fair(struct rq *rq, struct task_struct *p)
{
struct cfs_rq *cfs_rq = task_cfs_rq(p);
- struct sched_entity *se = &p->se;
+ struct sched_entity *se = &p->se, *curr = cfs_rq_curr(cfs_rq);
sched_info_queued(p);
+ update_curr(cfs_rq);
update_stats_enqueue(cfs_rq, se);
/*
* Child runs first: we let it run before the parent
* until it reschedules once. We set up the key so that
* it will preempt the parent:
*/
- p->se.fair_key = current->se.fair_key -
- niced_granularity(&rq->curr->se, sched_granularity(cfs_rq)) - 1;
+ se->fair_key = curr->fair_key -
+ niced_granularity(curr, sched_granularity(cfs_rq)) - 1;
/*
* The first wait is dominated by the child-runs-first logic,
* so do not credit it with that waiting time yet:
*/
if (sysctl_sched_features & SCHED_FEAT_SKIP_INITIAL)
- p->se.wait_start_fair = 0;
+ se->wait_start_fair = 0;
/*
* The statistical average of wait_runtime is about
* -granularity/2, so initialize the task with that:
*/
- if (sysctl_sched_features & SCHED_FEAT_START_DEBIT)
- p->se.wait_runtime = -(sched_granularity(cfs_rq) / 2);
+ if (sysctl_sched_features & SCHED_FEAT_START_DEBIT) {
+ se->wait_runtime = -(sched_granularity(cfs_rq) / 2);
+ schedstat_add(cfs_rq, wait_runtime, se->wait_runtime);
+ }
__enqueue_entity(cfs_rq, se);
}