From: Leo Yan <leo.yan@linaro.org>
To: Morten Rasmussen <morten.rasmussen@arm.com>
Cc: peterz@infradead.org, mingo@redhat.com,
vincent.guittot@linaro.org, daniel.lezcano@linaro.org,
Dietmar Eggemann <Dietmar.Eggemann@arm.com>,
yuyang.du@intel.com, mturquette@baylibre.com, rjw@rjwysocki.net,
Juri Lelli <Juri.Lelli@arm.com>,
sgurrappadi@nvidia.com, pang.xunlei@zte.com.cn,
linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org
Subject: Re: [RFCv5 PATCH 32/46] sched: Energy-aware wake-up task placement
Date: Thu, 3 Sep 2015 01:11:31 +0800 [thread overview]
Message-ID: <20150902171131.GA12510@leoy-linaro> (raw)
In-Reply-To: <1436293469-25707-33-git-send-email-morten.rasmussen@arm.com>
On Tue, Jul 07, 2015 at 07:24:15PM +0100, Morten Rasmussen wrote:
> Let available compute capacity and estimated energy impact select
> wake-up target cpu when energy-aware scheduling is enabled and the
> system in not over-utilized (above the tipping point).
>
> energy_aware_wake_cpu() attempts to find group of cpus with sufficient
> compute capacity to accommodate the task and find a cpu with enough spare
> capacity to handle the task within that group. Preference is given to
> cpus with enough spare capacity at the current OPP. Finally, the energy
> impact of the new target and the previous task cpu is compared to select
> the wake-up target cpu.
>
> cc: Ingo Molnar <mingo@redhat.com>
> cc: Peter Zijlstra <peterz@infradead.org>
>
> Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
> ---
> kernel/sched/fair.c | 85 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 84 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 0f7dbda4..01f7337 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -5427,6 +5427,86 @@ static int select_idle_sibling(struct task_struct *p, int target)
> return target;
> }
>
> +static int energy_aware_wake_cpu(struct task_struct *p, int target)
> +{
> + struct sched_domain *sd;
> + struct sched_group *sg, *sg_target;
> + int target_max_cap = INT_MAX;
> + int target_cpu = task_cpu(p);
> + int i;
> +
> + sd = rcu_dereference(per_cpu(sd_ea, task_cpu(p)));
> +
> + if (!sd)
> + return target;
> +
> + sg = sd->groups;
> + sg_target = sg;
> +
> + /*
> + * Find group with sufficient capacity. We only get here if no cpu is
> + * overutilized. We may end up overutilizing a cpu by adding the task,
> + * but that should not be any worse than select_idle_sibling().
> + * load_balance() should sort it out later as we get above the tipping
> + * point.
> + */
> + do {
> + /* Assuming all cpus are the same in group */
> + int max_cap_cpu = group_first_cpu(sg);
> +
> + /*
> + * Assume smaller max capacity means more energy-efficient.
> + * Ideally we should query the energy model for the right
> + * answer but it easily ends up in an exhaustive search.
> + */
> + if (capacity_of(max_cap_cpu) < target_max_cap &&
> + task_fits_capacity(p, max_cap_cpu)) {
> + sg_target = sg;
> + target_max_cap = capacity_of(max_cap_cpu);
> + }
Here should consider scenario for two groups have same capacity?
This will benefit for the case LITTLE.LITTLE. So the code will be
looks like below:
int target_sg_cpu = INT_MAX;
if (capacity_of(max_cap_cpu) <= target_max_cap &&
task_fits_capacity(p, max_cap_cpu)) {
if ((capacity_of(max_cap_cpu) == target_max_cap) &&
(target_sg_cpu < max_cap_cpu))
continue;
target_sg_cpu = max_cap_cpu;
sg_target = sg;
target_max_cap = capacity_of(max_cap_cpu);
}
> + } while (sg = sg->next, sg != sd->groups);
> +
> + /* Find cpu with sufficient capacity */
> + for_each_cpu_and(i, tsk_cpus_allowed(p), sched_group_cpus(sg_target)) {
> + /*
> + * p's blocked utilization is still accounted for on prev_cpu
> + * so prev_cpu will receive a negative bias due the double
> + * accouting. However, the blocked utilization may be zero.
> + */
> + int new_usage = get_cpu_usage(i) + task_utilization(p);
> +
> + if (new_usage > capacity_orig_of(i))
> + continue;
> +
> + if (new_usage < capacity_curr_of(i)) {
> + target_cpu = i;
> + if (cpu_rq(i)->nr_running)
> + break;
> + }
> +
> + /* cpu has capacity at higher OPP, keep it as fallback */
> + if (target_cpu == task_cpu(p))
> + target_cpu = i;
> + }
> +
> + if (target_cpu != task_cpu(p)) {
> + struct energy_env eenv = {
> + .usage_delta = task_utilization(p),
> + .src_cpu = task_cpu(p),
> + .dst_cpu = target_cpu,
> + };
> +
> + /* Not enough spare capacity on previous cpu */
> + if (cpu_overutilized(task_cpu(p)))
> + return target_cpu;
> +
> + if (energy_diff(&eenv) >= 0)
> + return task_cpu(p);
> + }
> +
> + return target_cpu;
> +}
> +
> /*
> * select_task_rq_fair: Select target runqueue for the waking task in domains
> * that have the 'sd_flag' flag set. In practice, this is SD_BALANCE_WAKE,
> @@ -5479,7 +5559,10 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f
> prev_cpu = cpu;
>
> if (sd_flag & SD_BALANCE_WAKE && want_sibling) {
> - new_cpu = select_idle_sibling(p, prev_cpu);
> + if (energy_aware() && !cpu_rq(cpu)->rd->overutilized)
> + new_cpu = energy_aware_wake_cpu(p, prev_cpu);
> + else
> + new_cpu = select_idle_sibling(p, prev_cpu);
> goto unlock;
> }
>
> --
> 1.9.1
>
> --
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> Please read the FAQ at http://www.tux.org/lkml/
next prev parent reply other threads:[~2015-09-02 17:11 UTC|newest]
Thread overview: 155+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-07 18:23 [RFCv5 PATCH 00/46] sched: Energy cost model for energy-aware scheduling Morten Rasmussen
2015-07-07 18:23 ` [RFCv5 PATCH 01/46] arm: Frequency invariant scheduler load-tracking support Morten Rasmussen
2015-07-21 15:41 ` [RFCv5, " Leo Yan
2015-07-22 13:31 ` Morten Rasmussen
2015-07-22 14:59 ` Leo Yan
2015-07-23 11:06 ` Morten Rasmussen
2015-07-23 14:22 ` Leo Yan
2015-07-24 9:43 ` Morten Rasmussen
2015-08-03 9:22 ` [RFCv5 PATCH " Vincent Guittot
2015-08-17 15:59 ` Dietmar Eggemann
2015-08-11 9:27 ` Peter Zijlstra
2015-08-14 16:08 ` Morten Rasmussen
2015-07-07 18:23 ` [RFCv5 PATCH 02/46] sched: Make load tracking frequency scale-invariant Morten Rasmussen
2015-07-07 18:23 ` [RFCv5 PATCH 03/46] arm: vexpress: Add CPU clock-frequencies to TC2 device-tree Morten Rasmussen
2015-07-08 12:36 ` Jon Medhurst (Tixy)
2015-07-10 13:35 ` Dietmar Eggemann
2015-07-07 18:23 ` [RFCv5 PATCH 04/46] sched: Convert arch_scale_cpu_capacity() from weak function to #define Morten Rasmussen
2015-07-07 18:23 ` [RFCv5 PATCH 05/46] arm: Update arch_scale_cpu_capacity() to reflect change to define Morten Rasmussen
2015-07-07 18:23 ` [RFCv5 PATCH 06/46] sched: Make usage tracking cpu scale-invariant Morten Rasmussen
2015-07-07 18:23 ` [RFCv5 PATCH 07/46] arm: Cpu invariant scheduler load-tracking support Morten Rasmussen
2015-07-07 18:23 ` [RFCv5 PATCH 08/46] sched: Get rid of scaling usage by cpu_capacity_orig Morten Rasmussen
2015-07-07 18:23 ` [RFCv5 PATCH 09/46] sched: Track blocked utilization contributions Morten Rasmussen
2015-07-07 18:23 ` [RFCv5 PATCH 10/46] sched: Include blocked utilization in usage tracking Morten Rasmussen
2015-07-07 18:23 ` [RFCv5 PATCH 11/46] sched: Remove blocked load and utilization contributions of dying tasks Morten Rasmussen
2015-07-22 6:51 ` Leo Yan
2015-07-22 13:45 ` Morten Rasmussen
2015-08-11 11:39 ` Peter Zijlstra
2015-08-11 14:58 ` Morten Rasmussen
2015-08-11 17:23 ` Peter Zijlstra
2015-08-12 9:08 ` Morten Rasmussen
2015-07-07 18:23 ` [RFCv5 PATCH 12/46] sched: Initialize CFS task load and usage before placing task on rq Morten Rasmussen
2015-07-07 18:23 ` [RFCv5 PATCH 13/46] sched: Documentation for scheduler energy cost model Morten Rasmussen
2015-07-07 18:23 ` [RFCv5 PATCH 14/46] sched: Make energy awareness a sched feature Morten Rasmussen
2015-07-07 18:23 ` [RFCv5 PATCH 15/46] sched: Introduce energy data structures Morten Rasmussen
2015-07-07 18:23 ` [RFCv5 PATCH 16/46] sched: Allocate and initialize " Morten Rasmussen
2015-08-12 10:04 ` Peter Zijlstra
2015-08-12 17:08 ` Dietmar Eggemann
2015-08-12 10:17 ` Peter Zijlstra
2015-08-12 17:09 ` Dietmar Eggemann
2015-08-12 17:23 ` Peter Zijlstra
2015-07-07 18:24 ` [RFCv5 PATCH 17/46] sched: Introduce SD_SHARE_CAP_STATES sched_domain flag Morten Rasmussen
2015-07-07 18:24 ` [RFCv5 PATCH 18/46] arm: topology: Define TC2 energy and provide it to the scheduler Morten Rasmussen
2015-08-12 10:33 ` Peter Zijlstra
2015-08-12 18:47 ` Dietmar Eggemann
2015-08-17 9:19 ` [RFCv5, " Leo Yan
2015-08-20 19:19 ` Dietmar Eggemann
2015-07-07 18:24 ` [RFCv5 PATCH 19/46] sched: Compute cpu capacity available at current frequency Morten Rasmussen
2015-07-07 18:24 ` [RFCv5 PATCH 20/46] sched: Relocated get_cpu_usage() and change return type Morten Rasmussen
2015-08-12 10:59 ` Peter Zijlstra
2015-08-12 14:40 ` Morten Rasmussen
2015-07-07 18:24 ` [RFCv5 PATCH 21/46] sched: Highest energy aware balancing sched_domain level pointer Morten Rasmussen
2015-07-07 18:24 ` [RFCv5 PATCH 22/46] sched: Calculate energy consumption of sched_group Morten Rasmussen
2015-08-13 15:34 ` Peter Zijlstra
2015-08-14 10:28 ` Morten Rasmussen
2015-09-02 17:19 ` Leo Yan
2015-09-17 16:41 ` Morten Rasmussen
2015-07-07 18:24 ` [RFCv5 PATCH 23/46] sched: Extend sched_group_energy to test load-balancing decisions Morten Rasmussen
2015-07-07 18:24 ` [RFCv5 PATCH 24/46] sched: Estimate energy impact of scheduling decisions Morten Rasmussen
2015-07-07 18:24 ` [RFCv5 PATCH 25/46] sched: Add over-utilization/tipping point indicator Morten Rasmussen
2015-08-13 17:35 ` Peter Zijlstra
2015-08-14 13:02 ` Morten Rasmussen
2015-09-29 20:08 ` Steve Muckle
2015-10-09 12:49 ` Morten Rasmussen
2015-08-17 13:10 ` Leo Yan
2015-07-07 18:24 ` [RFCv5 PATCH 26/46] sched: Store system-wide maximum cpu capacity in root domain Morten Rasmussen
2015-07-07 18:24 ` [RFCv5 PATCH 27/46] sched, cpuidle: Track cpuidle state index in the scheduler Morten Rasmussen
2015-07-21 6:41 ` Leo Yan
2015-07-21 15:16 ` Morten Rasmussen
2015-07-07 18:24 ` [RFCv5 PATCH 28/46] sched: Count number of shallower idle-states in struct sched_group_energy Morten Rasmussen
2015-08-13 18:10 ` Peter Zijlstra
2015-08-14 19:08 ` Sai Gurrappadi
2015-07-07 18:24 ` [RFCv5 PATCH 29/46] sched: Determine the current sched_group idle-state Morten Rasmussen
2015-07-07 18:24 ` [RFCv5 PATCH 30/46] sched: Add cpu capacity awareness to wakeup balancing Morten Rasmussen
2015-08-13 18:24 ` Peter Zijlstra
2015-08-14 16:20 ` Morten Rasmussen
2015-07-07 18:24 ` [RFCv5 PATCH 31/46] sched: Consider spare cpu capacity at task wake-up Morten Rasmussen
2015-07-21 0:37 ` Sai Gurrappadi
2015-07-21 15:12 ` Morten Rasmussen
2015-07-07 18:24 ` [RFCv5 PATCH 32/46] sched: Energy-aware wake-up task placement Morten Rasmussen
2015-07-17 0:10 ` Sai Gurrappadi
2015-07-20 15:38 ` Morten Rasmussen
2015-08-17 16:23 ` Leo Yan
2015-09-02 17:11 ` Leo Yan [this message]
2015-09-18 10:34 ` Dietmar Eggemann
2015-09-20 18:39 ` Steve Muckle
2015-09-20 22:03 ` Leo Yan
2015-09-29 0:15 ` Steve Muckle
2015-07-07 18:24 ` [RFCv5 PATCH 33/46] sched: Consider a not over-utilized energy-aware system as balanced Morten Rasmussen
2015-07-07 18:24 ` [RFCv5 PATCH 34/46] sched: Enable idle balance to pull single task towards cpu with higher capacity Morten Rasmussen
2015-08-15 9:15 ` Peter Zijlstra
2015-07-07 18:24 ` [RFCv5 PATCH 35/46] sched: Disable energy-unfriendly nohz kicks Morten Rasmussen
2015-08-15 9:33 ` Peter Zijlstra
2015-07-07 18:24 ` [RFCv5 PATCH 36/46] sched: Prevent unnecessary active balance of single task in sched group Morten Rasmussen
2015-08-15 9:46 ` Peter Zijlstra
2015-07-07 18:24 ` [RFCv5 PATCH 37/46] cpufreq: introduce cpufreq_driver_might_sleep Morten Rasmussen
2015-07-08 15:09 ` Michael Turquette
2015-07-07 18:24 ` [RFCv5 PATCH 38/46] sched: scheduler-driven cpu frequency selection Morten Rasmussen
2015-07-08 15:09 ` Michael Turquette
2015-08-11 2:14 ` Leo Yan
2015-08-11 8:59 ` Juri Lelli
2015-08-15 12:35 ` Peter Zijlstra
2015-09-04 13:27 ` Juri Lelli
2015-09-14 15:57 ` Juri Lelli
2015-09-15 13:45 ` Peter Zijlstra
2015-09-15 16:22 ` Juri Lelli
2015-08-15 13:05 ` Peter Zijlstra
2015-08-25 10:45 ` Juri Lelli
2015-10-08 0:14 ` Steve Muckle
2015-10-08 9:41 ` Juri Lelli
2015-09-28 16:48 ` Punit Agrawal
2015-09-29 0:26 ` Steve Muckle
2015-07-07 18:24 ` [RFCv5 PATCH 39/46] sched/cpufreq_sched: use static key for " Morten Rasmussen
2015-07-08 15:19 ` Michael Turquette
2015-07-10 9:50 ` Juri Lelli
2015-08-15 12:40 ` Peter Zijlstra
2015-07-07 18:24 ` [RFCv5 PATCH 40/46] sched/cpufreq_sched: compute freq_new based on capacity_orig_of() Morten Rasmussen
2015-07-08 15:22 ` Michael Turquette
2015-07-09 16:21 ` Juri Lelli
2015-08-15 12:46 ` Peter Zijlstra
2015-08-16 4:03 ` Michael Turquette
2015-08-16 20:24 ` Peter Zijlstra
2015-08-17 12:19 ` Juri Lelli
2015-10-13 19:47 ` Steve Muckle
2015-07-07 18:24 ` [RFCv5 PATCH 41/46] sched/fair: add triggers for OPP change requests Morten Rasmussen
2015-07-08 15:42 ` Michael Turquette
2015-07-09 16:52 ` Juri Lelli
2015-08-04 13:41 ` Vincent Guittot
2015-08-10 13:43 ` Juri Lelli
2015-08-10 15:07 ` Vincent Guittot
2015-08-11 9:08 ` Juri Lelli
2015-08-11 11:41 ` Vincent Guittot
2015-08-11 15:07 ` Juri Lelli
2015-08-11 16:37 ` Vincent Guittot
2015-08-12 15:15 ` Juri Lelli
2015-08-13 12:08 ` Vincent Guittot
2015-08-14 11:39 ` Juri Lelli
2015-08-17 9:43 ` Vincent Guittot
2015-08-15 12:48 ` Peter Zijlstra
2015-08-16 3:50 ` Michael Turquette
2015-08-17 18:22 ` Rafael J. Wysocki
2015-07-07 18:24 ` [RFCv5 PATCH 42/46] sched/{core,fair}: trigger OPP change request on fork() Morten Rasmussen
2015-07-07 18:24 ` [RFCv5 PATCH 43/46] sched/{fair,cpufreq_sched}: add reset_capacity interface Morten Rasmussen
2015-10-08 20:40 ` Steve Muckle
2015-10-09 9:14 ` Juri Lelli
2015-10-12 19:02 ` Steve Muckle
2015-07-07 18:24 ` [RFCv5 PATCH 44/46] sched/fair: jump to max OPP when crossing UP threshold Morten Rasmussen
2015-07-08 16:40 ` Michael Turquette
2015-07-08 16:47 ` Michael Turquette
2015-07-10 10:17 ` Juri Lelli
2015-07-07 18:24 ` [RFCv5 PATCH 45/46] sched/cpufreq_sched: modify pcpu_capacity handling Morten Rasmussen
2015-07-08 16:42 ` Michael Turquette
2015-07-09 16:55 ` Juri Lelli
2015-08-16 20:35 ` Peter Zijlstra
2015-08-17 11:16 ` Juri Lelli
2015-07-07 18:24 ` [RFCv5 PATCH 46/46] sched/fair: cpufreq_sched triggers for load balancing Morten Rasmussen
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