From: Alex Shi <alex.shi@intel.com>
To: mingo@redhat.com, peterz@infradead.org, tglx@linutronix.de,
akpm@linux-foundation.org, arjan@linux.intel.com, bp@alien8.de,
pjt@google.com, namhyung@kernel.org, efault@gmx.de,
morten.rasmussen@arm.com
Cc: vincent.guittot@linaro.org, gregkh@linuxfoundation.org,
preeti@linux.vnet.ibm.com, viresh.kumar@linaro.org,
linux-kernel@vger.kernel.org, alex.shi@intel.com,
len.brown@intel.com, rafael.j.wysocki@intel.com, jkosina@suse.cz,
clark.williams@gmail.com, tony.luck@intel.com,
keescook@chromium.org, mgorman@suse.de, riel@redhat.com
Subject: [patch v7 13/21] sched: packing transitory tasks in wakeup power balancing
Date: Thu, 4 Apr 2013 10:00:54 +0800 [thread overview]
Message-ID: <1365040862-8390-14-git-send-email-alex.shi@intel.com> (raw)
In-Reply-To: <1365040862-8390-1-git-send-email-alex.shi@intel.com>
If the waked task is transitory enough, it will has a chance to be
packed into a cpu which is busy but still has time to care it.
For powersaving policy, only the history util < 25% task has chance to
be packed. If there is no cpu eligible to handle it, will use a idlest
cpu in leader group.
Morten Rasmussen catch a type bug. And PeterZ reminder to consider
rt_util. thanks you!
Inspired-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Alex Shi <alex.shi@intel.com>
---
kernel/sched/fair.c | 54 +++++++++++++++++++++++++++++++++++++++++++++++------
1 file changed, 48 insertions(+), 6 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index a729939..6145ed2 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3449,19 +3449,60 @@ static inline int get_sd_sched_balance_policy(struct sched_domain *sd,
}
/*
+ * find_leader_cpu - find the busiest but still has enough free time cpu
+ * among the cpus in group.
+ */
+static int
+find_leader_cpu(struct sched_group *group, struct task_struct *p, int this_cpu,
+ int policy)
+{
+ int vacancy, min_vacancy = INT_MAX;
+ int leader_cpu = -1;
+ int i;
+ /* percentage of the task's util */
+ unsigned putil = (u64)(p->se.avg.runnable_avg_sum << SCHED_POWER_SHIFT)
+ / (p->se.avg.runnable_avg_period + 1);
+
+ /* bias toward local cpu */
+ if (cpumask_test_cpu(this_cpu, tsk_cpus_allowed(p)) &&
+ FULL_UTIL - max_rq_util(this_cpu) - (putil << 2) > 0)
+ return this_cpu;
+
+ /* Traverse only the allowed CPUs */
+ for_each_cpu_and(i, sched_group_cpus(group), tsk_cpus_allowed(p)) {
+ if (i == this_cpu)
+ continue;
+
+ /* only light task allowed, putil < 25% */
+ vacancy = FULL_UTIL - max_rq_util(i) - (putil << 2);
+
+ if (vacancy > 0 && vacancy < min_vacancy) {
+ min_vacancy = vacancy;
+ leader_cpu = i;
+ }
+ }
+ return leader_cpu;
+}
+
+/*
* If power policy is eligible for this domain, and it has task allowed cpu.
* we will select CPU from this domain.
*/
static int get_cpu_for_power_policy(struct sched_domain *sd, int cpu,
- struct task_struct *p, struct sd_lb_stats *sds)
+ struct task_struct *p, struct sd_lb_stats *sds, int wakeup)
{
int policy;
int new_cpu = -1;
policy = get_sd_sched_balance_policy(sd, cpu, p, sds);
- if (policy != SCHED_POLICY_PERFORMANCE && sds->group_leader)
- new_cpu = find_idlest_cpu(sds->group_leader, p, cpu);
-
+ if (policy != SCHED_POLICY_PERFORMANCE && sds->group_leader) {
+ if (wakeup)
+ new_cpu = find_leader_cpu(sds->group_leader,
+ p, cpu, policy);
+ /* for fork balancing and a little busy task */
+ if (new_cpu == -1)
+ new_cpu = find_idlest_cpu(sds->group_leader, p, cpu);
+ }
return new_cpu;
}
@@ -3512,14 +3553,15 @@ select_task_rq_fair(struct task_struct *p, int sd_flag, int flags)
if (tmp->flags & sd_flag) {
sd = tmp;
- new_cpu = get_cpu_for_power_policy(sd, cpu, p, &sds);
+ new_cpu = get_cpu_for_power_policy(sd, cpu, p, &sds,
+ sd_flag & SD_BALANCE_WAKE);
if (new_cpu != -1)
goto unlock;
}
}
if (affine_sd) {
- new_cpu = get_cpu_for_power_policy(affine_sd, cpu, p, &sds);
+ new_cpu = get_cpu_for_power_policy(affine_sd, cpu, p, &sds, 1);
if (new_cpu != -1)
goto unlock;
--
1.7.12
next prev parent reply other threads:[~2013-04-04 2:02 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-04 2:00 [patch v7 0/21] sched: power aware scheduling Alex Shi
2013-04-04 2:00 ` [patch v7 01/21] Revert "sched: Introduce temporary FAIR_GROUP_SCHED dependency for load-tracking" Alex Shi
2013-04-04 2:00 ` [patch v7 02/21] sched: set initial value of runnable avg for new forked task Alex Shi
2013-05-06 3:24 ` Preeti U Murthy
2013-04-04 2:00 ` [patch v7 03/21] sched: add sched balance policies in kernel Alex Shi
2013-04-04 2:00 ` [patch v7 04/21] sched: add sysfs interface for sched_balance_policy selection Alex Shi
2013-04-04 2:00 ` [patch v7 05/21] sched: log the cpu utilization at rq Alex Shi
2013-05-06 3:26 ` Preeti U Murthy
2013-05-06 5:22 ` Alex Shi
2013-05-06 12:03 ` Phil Carmody
2013-05-06 12:35 ` Alex Shi
2013-05-06 21:19 ` Paul Turner
2013-04-04 2:00 ` [patch v7 06/21] sched: add new sg/sd_lb_stats fields for incoming fork/exec/wake balancing Alex Shi
2013-04-04 2:00 ` [patch v7 07/21] sched: move sg/sd_lb_stats struct ahead Alex Shi
2013-04-04 2:00 ` [patch v7 08/21] sched: scale_rt_power rename and meaning change Alex Shi
2013-04-04 2:00 ` [patch v7 09/21] sched: get rq potential maximum utilization Alex Shi
2013-04-04 2:00 ` [patch v7 10/21] sched: add power aware scheduling in fork/exec/wake Alex Shi
2013-04-04 2:00 ` [patch v7 11/21] sched: add sched_burst_threshold_ns as wakeup burst indicator Alex Shi
2013-04-04 2:00 ` [patch v7 12/21] sched: using avg_idle to detect bursty wakeup Alex Shi
2013-04-04 2:00 ` Alex Shi [this message]
2013-04-04 2:00 ` [patch v7 14/21] sched: add power/performance balance allow flag Alex Shi
2013-04-04 2:00 ` [patch v7 15/21] sched: pull all tasks from source group Alex Shi
2013-04-04 5:59 ` Namhyung Kim
2013-04-06 11:49 ` Alex Shi
2013-04-04 2:00 ` [patch v7 16/21] sched: no balance for prefer_sibling in power scheduling Alex Shi
2013-05-06 3:26 ` Preeti U Murthy
2013-04-04 2:00 ` [patch v7 17/21] sched: add new members of sd_lb_stats Alex Shi
2013-04-04 2:00 ` [patch v7 18/21] sched: power aware load balance Alex Shi
2013-04-04 2:01 ` [patch v7 19/21] sched: lazy power balance Alex Shi
2013-04-04 2:01 ` [patch v7 20/21] sched: don't do power balance on share cpu power domain Alex Shi
2013-04-08 3:17 ` Preeti U Murthy
2013-04-08 3:25 ` Preeti U Murthy
2013-04-08 4:19 ` Alex Shi
2013-04-04 2:01 ` [patch v7 21/21] sched: make sure select_tas_rq_fair get a cpu Alex Shi
2013-04-11 21:02 ` [patch v7 0/21] sched: power aware scheduling Len Brown
2013-04-12 8:46 ` Alex Shi
2013-04-12 16:23 ` Borislav Petkov
2013-04-12 16:48 ` Mike Galbraith
2013-04-12 17:12 ` Borislav Petkov
2013-04-14 1:36 ` Alex Shi
2013-04-17 21:53 ` Len Brown
2013-04-18 1:51 ` Mike Galbraith
2013-04-26 15:11 ` Mike Galbraith
2013-04-30 5:16 ` Mike Galbraith
2013-04-30 8:30 ` Mike Galbraith
2013-04-30 8:41 ` Ingo Molnar
2013-04-30 9:35 ` Mike Galbraith
2013-04-30 9:49 ` Mike Galbraith
2013-04-30 9:56 ` Mike Galbraith
2013-05-17 8:06 ` Preeti U Murthy
2013-05-20 1:01 ` Alex Shi
2013-05-20 2:30 ` Preeti U Murthy
2013-04-14 1:28 ` Alex Shi
2013-04-14 5:10 ` Alex Shi
2013-04-14 15:59 ` Borislav Petkov
2013-04-15 6:04 ` Alex Shi
2013-04-15 6:16 ` Alex Shi
2013-04-15 9:52 ` Borislav Petkov
2013-04-15 13:50 ` Alex Shi
2013-04-15 23:12 ` Borislav Petkov
2013-04-16 0:22 ` Alex Shi
2013-04-16 10:24 ` Borislav Petkov
2013-04-17 1:18 ` Alex Shi
2013-04-17 7:38 ` Borislav Petkov
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