From: Vincent Guittot <vincent.guittot@linaro.org>
To: Morten Rasmussen <morten.rasmussen@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
"mingo@redhat.com" <mingo@redhat.com>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
Dietmar Eggemann <Dietmar.Eggemann@arm.com>,
Yuyang Du <yuyang.du@intel.com>,
Michael Turquette <mturquette@baylibre.com>,
"rjw@rjwysocki.net" <rjw@rjwysocki.net>,
Juri Lelli <Juri.Lelli@arm.com>,
Sai Charan Gurrappadi <sgurrappadi@nvidia.com>,
pang.xunlei@zte.com.cn,
linux-kernel <linux-kernel@vger.kernel.org>,
"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>
Subject: Re: [RFCv5 PATCH 41/46] sched/fair: add triggers for OPP change requests
Date: Tue, 4 Aug 2015 15:41:34 +0200 [thread overview]
Message-ID: <CAKfTPtBfNV=K+gwb7dfQXqBEbByMWRoFDb0FtfeeY1hh33j4XA@mail.gmail.com> (raw)
In-Reply-To: <1436293469-25707-42-git-send-email-morten.rasmussen@arm.com>
Hi Juri,
On 7 July 2015 at 20:24, Morten Rasmussen <morten.rasmussen@arm.com> wrote:
> From: Juri Lelli <juri.lelli@arm.com>
>
> Each time a task is {en,de}queued we might need to adapt the current
> frequency to the new usage. Add triggers on {en,de}queue_task_fair() for
> this purpose. Only trigger a freq request if we are effectively waking up
> or going to sleep. Filter out load balancing related calls to reduce the
> number of triggers.
>
> cc: Ingo Molnar <mingo@redhat.com>
> cc: Peter Zijlstra <peterz@infradead.org>
>
> Signed-off-by: Juri Lelli <juri.lelli@arm.com>
> ---
> kernel/sched/fair.c | 42 ++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 40 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index f74e9d2..b8627c6 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -4281,7 +4281,10 @@ static inline void hrtick_update(struct rq *rq)
> }
> #endif
>
> +static unsigned int capacity_margin = 1280; /* ~20% margin */
> +
> static bool cpu_overutilized(int cpu);
> +static unsigned long get_cpu_usage(int cpu);
> struct static_key __sched_energy_freq __read_mostly = STATIC_KEY_INIT_FALSE;
>
> /*
> @@ -4332,6 +4335,26 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
> if (!task_new && !rq->rd->overutilized &&
> cpu_overutilized(rq->cpu))
> rq->rd->overutilized = true;
> + /*
> + * We want to trigger a freq switch request only for tasks that
> + * are waking up; this is because we get here also during
> + * load balancing, but in these cases it seems wise to trigger
> + * as single request after load balancing is done.
> + *
> + * XXX: how about fork()? Do we need a special flag/something
> + * to tell if we are here after a fork() (wakeup_task_new)?
> + *
> + * Also, we add a margin (same ~20% used for the tipping point)
> + * to our request to provide some head room if p's utilization
> + * further increases.
> + */
> + if (sched_energy_freq() && !task_new) {
> + unsigned long req_cap = get_cpu_usage(cpu_of(rq));
> +
> + req_cap = req_cap * capacity_margin
> + >> SCHED_CAPACITY_SHIFT;
> + cpufreq_sched_set_cap(cpu_of(rq), req_cap);
> + }
> }
> hrtick_update(rq);
> }
> @@ -4393,6 +4416,23 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags)
> if (!se) {
> sub_nr_running(rq, 1);
> update_rq_runnable_avg(rq, 1);
> + /*
> + * We want to trigger a freq switch request only for tasks that
> + * are going to sleep; this is because we get here also during
> + * load balancing, but in these cases it seems wise to trigger
> + * as single request after load balancing is done.
> + *
> + * Also, we add a margin (same ~20% used for the tipping point)
> + * to our request to provide some head room if p's utilization
> + * further increases.
> + */
> + if (sched_energy_freq() && task_sleep) {
> + unsigned long req_cap = get_cpu_usage(cpu_of(rq));
> +
> + req_cap = req_cap * capacity_margin
> + >> SCHED_CAPACITY_SHIFT;
> + cpufreq_sched_set_cap(cpu_of(rq), req_cap);
Could you clarify why you want to trig a freq switch for tasks that
are going to sleep ?
The cpu_usage should not changed that much as the se_utilization of
the entity moves from utilization_load_avg to utilization_blocked_avg
of the rq and the usage and the freq are updated periodically.
It should be the same for the wake up of a task in enqueue_task_fair
above, even if it's less obvious for this latter use case because the
cpu might wake up from a long idle phase during which its
utilization_blocked_avg has not been updated. Nevertheless, a trig of
the freq switch at wake up of the cpu once its usage has been updated
should do the job.
So tick, migration of tasks, new tasks, entering/leaving idle state of
cpu should be enough to trig freq switch
Regards,
Vincent
> + }
> }
> hrtick_update(rq);
> }
> @@ -4959,8 +4999,6 @@ static int find_new_capacity(struct energy_env *eenv,
> return idx;
> }
>
> -static unsigned int capacity_margin = 1280; /* ~20% margin */
> -
> static bool cpu_overutilized(int cpu)
> {
> return (capacity_of(cpu) * 1024) <
> --
> 1.9.1
>
next prev parent reply other threads:[~2015-08-04 13:41 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
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 [this message]
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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