From: Morten Rasmussen <morten.rasmussen@arm.com>
To: Sai Gurrappadi <sgurrappadi@nvidia.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>,
pang.xunlei@zte.com.cn, linux-kernel@vger.kernel.org,
linux-pm@vger.kernel.org, pboonstoppel@nvidia.com
Subject: Re: [RFCv5 PATCH 32/46] sched: Energy-aware wake-up task placement
Date: Mon, 20 Jul 2015 16:38:26 +0100 [thread overview]
Message-ID: <20150720153826.GA15088@e105550-lin.cambridge.arm.com> (raw)
In-Reply-To: <55A8480C.6080806@nvidia.com>
On Thu, Jul 16, 2015 at 05:10:52PM -0700, Sai Gurrappadi wrote:
> Hi Morten,
>
> On 07/07/2015 11:24 AM, Morten Rasmussen wrote:
> > ---
>
> > +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);
> > + }
> > + } while (sg = sg->next, sg != sd->groups);
>
> Should be capacity_orig_of(max_cap_cpu) right? Might select a suboptimal
> sg_target if max_cap_cpu has a significant amount of IRQ/RT activity.
Right, this heuristic isn't as good as I had hoped for.
task_fits_capacity() is using capacity_of() to check if we have
available capacity after subtracting RT/IRQ activity which should be
right but I only check the first cpu. So I might discard a group due to
RT/IRQ activity on cpu the first cpu while one the sibling cpus could be
fine. Then going for lowest capacity_of() means preferring group with
most RT/IRQ activity that still has enough capacity to fit the task.
Using capacity_orig_of() we would ignore RT/IRQ activity but is likely
to be better as we can try to avoid RQ/IRQ activity later. I will use
capacity_orig_of() here instead. Thanks.
> > +
> > + /* 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;
>
> Is this supposed to be capacity_of(i) instead?
Yes, we should skip cpus with too much RT/IRQ activity here. Thanks.
Morten
next prev parent reply other threads:[~2015-07-20 15:35 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 [this message]
2015-08-17 16:23 ` Leo Yan
2015-09-02 17:11 ` Leo Yan
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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