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authorMike Galbraith <efault@gmx.de>2010-03-11 17:15:38 +0100
committerIngo Molnar <mingo@elte.hu>2010-03-11 18:32:50 +0100
commitb42e0c41a422a212ddea0666d5a3a0e3c35206db (patch)
tree443cf5918548cab86c3f9f3f34a1b700d809070b
parent39c0cbe2150cbd848a25ba6cdb271d1ad46818ad (diff)
downloadop-kernel-dev-b42e0c41a422a212ddea0666d5a3a0e3c35206db.zip
op-kernel-dev-b42e0c41a422a212ddea0666d5a3a0e3c35206db.tar.gz
sched: Remove avg_wakeup
Testing the load which led to this heuristic (nfs4 kbuild) shows that it has outlived it's usefullness. With intervening load balancing changes, I cannot see any difference with/without, so recover there fastpath cycles. Signed-off-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1268301062.6785.29.camel@marge.simson.net> Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--include/linux/sched.h3
-rw-r--r--kernel/sched.c26
-rw-r--r--kernel/sched_debug.c1
-rw-r--r--kernel/sched_fair.c31
-rw-r--r--kernel/sched_features.h6
5 files changed, 4 insertions, 63 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 13efe7d..70c560f 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1185,9 +1185,6 @@ struct sched_entity {
u64 nr_migrations;
- u64 start_runtime;
- u64 avg_wakeup;
-
#ifdef CONFIG_SCHEDSTATS
struct sched_statistics statistics;
#endif
diff --git a/kernel/sched.c b/kernel/sched.c
index 60b1bbe..35a8626 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -1880,9 +1880,6 @@ static void update_avg(u64 *avg, u64 sample)
static void
enqueue_task(struct rq *rq, struct task_struct *p, int wakeup, bool head)
{
- if (wakeup)
- p->se.start_runtime = p->se.sum_exec_runtime;
-
sched_info_queued(p);
p->sched_class->enqueue_task(rq, p, wakeup, head);
p->se.on_rq = 1;
@@ -1890,17 +1887,11 @@ enqueue_task(struct rq *rq, struct task_struct *p, int wakeup, bool head)
static void dequeue_task(struct rq *rq, struct task_struct *p, int sleep)
{
- if (sleep) {
- if (p->se.last_wakeup) {
- update_avg(&p->se.avg_overlap,
- p->se.sum_exec_runtime - p->se.last_wakeup);
- p->se.last_wakeup = 0;
- } else {
- update_avg(&p->se.avg_wakeup,
- sysctl_sched_wakeup_granularity);
- }
+ if (sleep && p->se.last_wakeup) {
+ update_avg(&p->se.avg_overlap,
+ p->se.sum_exec_runtime - p->se.last_wakeup);
+ p->se.last_wakeup = 0;
}
-
sched_info_dequeued(p);
p->sched_class->dequeue_task(rq, p, sleep);
p->se.on_rq = 0;
@@ -2466,13 +2457,6 @@ out_activate:
*/
if (!in_interrupt()) {
struct sched_entity *se = &current->se;
- u64 sample = se->sum_exec_runtime;
-
- if (se->last_wakeup)
- sample -= se->last_wakeup;
- else
- sample -= se->start_runtime;
- update_avg(&se->avg_wakeup, sample);
se->last_wakeup = se->sum_exec_runtime;
}
@@ -2540,8 +2524,6 @@ static void __sched_fork(struct task_struct *p)
p->se.nr_migrations = 0;
p->se.last_wakeup = 0;
p->se.avg_overlap = 0;
- p->se.start_runtime = 0;
- p->se.avg_wakeup = sysctl_sched_wakeup_granularity;
#ifdef CONFIG_SCHEDSTATS
memset(&p->se.statistics, 0, sizeof(p->se.statistics));
diff --git a/kernel/sched_debug.c b/kernel/sched_debug.c
index ad9df44..20b95a4 100644
--- a/kernel/sched_debug.c
+++ b/kernel/sched_debug.c
@@ -408,7 +408,6 @@ void proc_sched_show_task(struct task_struct *p, struct seq_file *m)
PN(se.vruntime);
PN(se.sum_exec_runtime);
PN(se.avg_overlap);
- PN(se.avg_wakeup);
nr_switches = p->nvcsw + p->nivcsw;
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 8ad164b..6fc6285 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -1592,42 +1592,11 @@ static int select_task_rq_fair(struct task_struct *p, int sd_flag, int wake_flag
}
#endif /* CONFIG_SMP */
-/*
- * Adaptive granularity
- *
- * se->avg_wakeup gives the average time a task runs until it does a wakeup,
- * with the limit of wakeup_gran -- when it never does a wakeup.
- *
- * So the smaller avg_wakeup is the faster we want this task to preempt,
- * but we don't want to treat the preemptee unfairly and therefore allow it
- * to run for at least the amount of time we'd like to run.
- *
- * NOTE: we use 2*avg_wakeup to increase the probability of actually doing one
- *
- * NOTE: we use *nr_running to scale with load, this nicely matches the
- * degrading latency on load.
- */
-static unsigned long
-adaptive_gran(struct sched_entity *curr, struct sched_entity *se)
-{
- u64 this_run = curr->sum_exec_runtime - curr->prev_sum_exec_runtime;
- u64 expected_wakeup = 2*se->avg_wakeup * cfs_rq_of(se)->nr_running;
- u64 gran = 0;
-
- if (this_run < expected_wakeup)
- gran = expected_wakeup - this_run;
-
- return min_t(s64, gran, sysctl_sched_wakeup_granularity);
-}
-
static unsigned long
wakeup_gran(struct sched_entity *curr, struct sched_entity *se)
{
unsigned long gran = sysctl_sched_wakeup_granularity;
- if (cfs_rq_of(curr)->curr && sched_feat(ADAPTIVE_GRAN))
- gran = adaptive_gran(curr, se);
-
/*
* Since its curr running now, convert the gran from real-time
* to virtual-time in his units.
diff --git a/kernel/sched_features.h b/kernel/sched_features.h
index d5059fd..96ef5db 100644
--- a/kernel/sched_features.h
+++ b/kernel/sched_features.h
@@ -31,12 +31,6 @@ SCHED_FEAT(START_DEBIT, 1)
SCHED_FEAT(WAKEUP_PREEMPT, 1)
/*
- * Compute wakeup_gran based on task behaviour, clipped to
- * [0, sched_wakeup_gran_ns]
- */
-SCHED_FEAT(ADAPTIVE_GRAN, 1)
-
-/*
* When converting the wakeup granularity to virtual time, do it such
* that heavier tasks preempting a lighter task have an edge.
*/
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