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sched: Optimize cgroup vs wakeup a bit

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We don't need to call update_shares() for each domain we iterate,
just got the largets one.

However, we should call it before wake_affine() as well, so that
that can use up-to-date values too.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra
2009-09-16 13:44:33 +02:00
committed by Ingo Molnar
parent 7c423e9885
commit 3b64089422
3 changed files with 10 additions and 22 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
kernel/sched.c
View File

@@ -376,13 +376,6 @@ static inline void set_task_rq(struct task_struct *p, unsigned int cpu)
#else #else
#ifdef CONFIG_SMP
static int root_task_group_empty(void)
{
return 1;
}
#endif
static inline void set_task_rq(struct task_struct *p, unsigned int cpu) { } static inline void set_task_rq(struct task_struct *p, unsigned int cpu) { }
static inline struct task_group *task_group(struct task_struct *p) static inline struct task_group *task_group(struct task_struct *p)
{ {

23
kernel/sched_fair.c
View File

@@ -1348,7 +1348,7 @@ find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu)
*/ */
static int select_task_rq_fair(struct task_struct *p, int sd_flag, int flags) static int select_task_rq_fair(struct task_struct *p, int sd_flag, int flags)
{ {
struct sched_domain *tmp, *sd = NULL; struct sched_domain *tmp, *shares = NULL, *sd = NULL;
int cpu = smp_processor_id(); int cpu = smp_processor_id();
int prev_cpu = task_cpu(p); int prev_cpu = task_cpu(p);
int new_cpu = cpu; int new_cpu = cpu;
@@ -1387,22 +1387,14 @@ static int select_task_rq_fair(struct task_struct *p, int sd_flag, int flags)
break; break;
} }
switch (sd_flag) {
case SD_BALANCE_WAKE:
if (!sched_feat(LB_WAKEUP_UPDATE))
break;
case SD_BALANCE_FORK:
case SD_BALANCE_EXEC:
if (root_task_group_empty())
break;
update_shares(tmp);
default:
break;
}
if (want_affine && (tmp->flags & SD_WAKE_AFFINE) && if (want_affine && (tmp->flags & SD_WAKE_AFFINE) &&
cpumask_test_cpu(prev_cpu, sched_domain_span(tmp))) { cpumask_test_cpu(prev_cpu, sched_domain_span(tmp))) {
if (sched_feat(LB_SHARES_UPDATE)) {
update_shares(tmp);
shares = tmp;
}
if (wake_affine(tmp, p, sync)) { if (wake_affine(tmp, p, sync)) {
new_cpu = cpu; new_cpu = cpu;
goto out; goto out;
@@ -1417,6 +1409,9 @@ static int select_task_rq_fair(struct task_struct *p, int sd_flag, int flags)
sd = tmp; sd = tmp;
} }
if (sd && sd != shares && sched_feat(LB_SHARES_UPDATE))
update_shares(sd);
while (sd) { while (sd) {
struct sched_group *group; struct sched_group *group;
int weight; int weight;

2
kernel/sched_features.h
View File

@@ -107,7 +107,7 @@ SCHED_FEAT(ARCH_POWER, 0)
SCHED_FEAT(HRTICK, 0) SCHED_FEAT(HRTICK, 0)
SCHED_FEAT(DOUBLE_TICK, 0) SCHED_FEAT(DOUBLE_TICK, 0)
SCHED_FEAT(LB_BIAS, 1) SCHED_FEAT(LB_BIAS, 1)
SCHED_FEAT(LB_WAKEUP_UPDATE, 1) SCHED_FEAT(LB_SHARES_UPDATE, 1)
SCHED_FEAT(ASYM_EFF_LOAD, 1) SCHED_FEAT(ASYM_EFF_LOAD, 1)
/* /*