From: Valentin Schneider <valentin.schneider@arm.com>
To: Quentin Perret <quentin.perret@arm.com>,
peterz@infradead.org, rjw@rjwysocki.net,
linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org
Cc: gregkh@linuxfoundation.org, mingo@redhat.com,
dietmar.eggemann@arm.com, morten.rasmussen@arm.com,
chris.redpath@arm.com, patrick.bellasi@arm.com,
vincent.guittot@linaro.org, thara.gopinath@linaro.org,
viresh.kumar@linaro.org, tkjos@google.com,
joel@joelfernandes.org, smuckle@google.com, adharmap@quicinc.com,
skannan@quicinc.com, pkondeti@codeaurora.org,
juri.lelli@redhat.com, edubezval@gmail.com,
srinivas.pandruvada@linux.intel.com, currojerez@riseup.net,
javi.merino@kernel.org
Subject: Re: [PATCH v5 06/14] sched/topology: Lowest energy aware balancing sched_domain level pointer
Date: Thu, 26 Jul 2018 17:00:50 +0100 [thread overview]
Message-ID: <76777be2-0f70-ca54-21a8-5af77a47ea86@arm.com> (raw)
In-Reply-To: <20180724122521.22109-7-quentin.perret@arm.com>
Hi,
On 24/07/18 13:25, Quentin Perret wrote:
> Add another member to the family of per-cpu sched_domain shortcut
> pointers. This one, sd_ea, points to the lowest level at which energy
> aware scheduling should be used.
>
> Generally speaking, the largest opportunity to save energy via scheduling
> comes from a smarter exploitation of heterogeneous platforms (i.e.
> big.LITTLE). Consequently, the sd_ea shortcut is wired to the lowest
> scheduling domain at which the SD_ASYM_CPUCAPACITY flag is set. For
> example, it is possible to apply Energy-Aware Scheduling within a socket
> on a multi-socket system, as long as each socket has an asymmetric
> topology. Cross-sockets wake-up balancing will only happen when the
> system is over-utilized, or this_cpu and prev_cpu are in different
> sockets.
>
> cc: Ingo Molnar <mingo@redhat.com>
> cc: Peter Zijlstra <peterz@infradead.org>
> Suggested-by: Morten Rasmussen <morten.rasmussen@arm.com>
> Signed-off-by: Quentin Perret <quentin.perret@arm.com>
> ---
> kernel/sched/sched.h | 1 +
> kernel/sched/topology.c | 4 ++++
> 2 files changed, 5 insertions(+)
>
> diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
> index fdf6924d53e7..25d64a0b6fe0 100644
> --- a/kernel/sched/sched.h
> +++ b/kernel/sched/sched.h
> @@ -1198,6 +1198,7 @@ DECLARE_PER_CPU(int, sd_llc_id);
> DECLARE_PER_CPU(struct sched_domain_shared *, sd_llc_shared);
> DECLARE_PER_CPU(struct sched_domain *, sd_numa);
> DECLARE_PER_CPU(struct sched_domain *, sd_asym);
> +DECLARE_PER_CPU(struct sched_domain *, sd_ea);
There's already the asym-packing shortcut which is making naming a bit more
tedious, but should that really be named energy-aware? IMO it's just the
lowest level at which we can see asymmetry, so perhaps it should be named
as such, i.e. something like sd_asym_capa (and perhaps rename the other one
as sd_asym_pack)?
>
> struct sched_group_capacity {
> atomic_t ref;
> diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
> index ade1eae9d21b..8f3f746b0d5e 100644
> --- a/kernel/sched/topology.c
> +++ b/kernel/sched/topology.c
> @@ -514,6 +514,7 @@ DEFINE_PER_CPU(int, sd_llc_id);
> DEFINE_PER_CPU(struct sched_domain_shared *, sd_llc_shared);
> DEFINE_PER_CPU(struct sched_domain *, sd_numa);
> DEFINE_PER_CPU(struct sched_domain *, sd_asym);
> +DEFINE_PER_CPU(struct sched_domain *, sd_ea);
>
> static void update_top_cache_domain(int cpu)
> {
> @@ -539,6 +540,9 @@ static void update_top_cache_domain(int cpu)
>
> sd = highest_flag_domain(cpu, SD_ASYM_PACKING);
> rcu_assign_pointer(per_cpu(sd_asym, cpu), sd);
> +
> + sd = lowest_flag_domain(cpu, SD_ASYM_CPUCAPACITY);
> + rcu_assign_pointer(per_cpu(sd_ea, cpu), sd);
> }
>
> /*
>
next prev parent reply other threads:[~2018-07-26 16:00 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-24 12:25 [PATCH v5 00/14] Energy Aware Scheduling Quentin Perret
2018-07-24 12:25 ` [PATCH v5 01/14] sched: Relocate arch_scale_cpu_capacity Quentin Perret
2018-07-24 12:25 ` [PATCH v5 02/14] sched/cpufreq: Factor out utilization to frequency mapping Quentin Perret
2018-07-24 12:25 ` [PATCH v5 03/14] PM: Introduce an Energy Model management framework Quentin Perret
2018-08-09 21:52 ` Rafael J. Wysocki
2018-08-10 8:15 ` Quentin Perret
2018-08-10 8:41 ` Rafael J. Wysocki
2018-08-10 9:12 ` Quentin Perret
2018-08-10 11:13 ` Rafael J. Wysocki
2018-08-10 12:30 ` Quentin Perret
2018-08-12 9:49 ` Rafael J. Wysocki
2018-07-24 12:25 ` [PATCH v5 04/14] PM / EM: Expose the Energy Model in sysfs Quentin Perret
2018-07-24 12:25 ` [PATCH v5 05/14] sched/topology: Reference the Energy Model of CPUs when available Quentin Perret
2018-07-24 12:25 ` [PATCH v5 06/14] sched/topology: Lowest energy aware balancing sched_domain level pointer Quentin Perret
2018-07-26 16:00 ` Valentin Schneider [this message]
2018-07-26 17:01 ` Quentin Perret
2018-07-24 12:25 ` [PATCH v5 07/14] sched/topology: Introduce sched_energy_present static key Quentin Perret
2018-07-24 12:25 ` [PATCH v5 08/14] sched/fair: Clean-up update_sg_lb_stats parameters Quentin Perret
2018-07-24 12:25 ` [PATCH v5 09/14] sched: Add over-utilization/tipping point indicator Quentin Perret
2018-08-02 12:26 ` Peter Zijlstra
2018-08-02 13:03 ` Quentin Perret
2018-08-02 13:08 ` Peter Zijlstra
2018-08-02 13:18 ` Quentin Perret
2018-08-02 13:48 ` Vincent Guittot
2018-08-02 14:14 ` Quentin Perret
2018-08-02 15:14 ` Vincent Guittot
2018-08-02 15:30 ` Quentin Perret
2018-08-02 15:55 ` Vincent Guittot
2018-08-02 16:00 ` Quentin Perret
2018-08-02 16:07 ` Vincent Guittot
2018-08-02 16:10 ` Quentin Perret
2018-08-02 16:38 ` Vincent Guittot
2018-08-02 16:59 ` Quentin Perret
2018-08-03 7:48 ` Vincent Guittot
2018-08-03 8:18 ` Quentin Perret
2018-08-03 13:49 ` Vincent Guittot
2018-08-03 14:21 ` Vincent Guittot
2018-08-03 15:55 ` Quentin Perret
2018-08-06 8:40 ` Vincent Guittot
2018-08-06 9:43 ` Quentin Perret
2018-08-06 10:45 ` Vincent Guittot
2018-08-06 11:02 ` Quentin Perret
2018-08-06 10:08 ` Dietmar Eggemann
2018-08-06 10:33 ` Vincent Guittot
2018-08-06 12:29 ` Dietmar Eggemann
2018-08-06 12:37 ` Vincent Guittot
2018-08-06 13:20 ` Dietmar Eggemann
2018-08-09 9:30 ` Vincent Guittot
2018-08-09 9:38 ` Quentin Perret
2018-07-24 12:25 ` [PATCH v5 10/14] sched/cpufreq: Refactor the utilization aggregation method Quentin Perret
2018-07-30 19:35 ` skannan
2018-07-31 7:59 ` Quentin Perret
2018-07-31 19:31 ` skannan
2018-08-01 7:32 ` Rafael J. Wysocki
2018-08-01 8:23 ` Quentin Perret
2018-08-01 8:35 ` Rafael J. Wysocki
2018-08-01 9:23 ` Quentin Perret
2018-08-01 9:40 ` Rafael J. Wysocki
2018-08-02 13:04 ` Peter Zijlstra
2018-08-02 15:39 ` Quentin Perret
2018-08-03 13:04 ` Quentin Perret
2018-08-02 12:33 ` Peter Zijlstra
2018-08-02 12:45 ` Peter Zijlstra
2018-08-02 15:21 ` Quentin Perret
2018-08-02 17:36 ` Peter Zijlstra
2018-08-03 12:42 ` Quentin Perret
2018-07-24 12:25 ` [PATCH v5 11/14] sched/fair: Introduce an energy estimation helper function Quentin Perret
2018-07-24 12:25 ` [PATCH v5 12/14] sched/fair: Select an energy-efficient CPU on task wake-up Quentin Perret
2018-08-02 13:54 ` Peter Zijlstra
2018-08-02 16:21 ` Quentin Perret
2018-07-24 12:25 ` [PATCH v5 13/14] OPTIONAL: arch_topology: Start Energy Aware Scheduling Quentin Perret
2018-07-24 12:25 ` [PATCH v5 14/14] OPTIONAL: cpufreq: dt: Register an Energy Model Quentin Perret
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