From: Quentin Perret <quentin.perret@arm.com>
To: 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,
valentin.schneider@arm.com, vincent.guittot@linaro.org,
thara.gopinath@linaro.org, viresh.kumar@linaro.org,
tkjos@google.com, joel@joelfernandes.org, smuckle@google.com,
adharmap@codeaurora.org, skannan@codeaurora.org,
pkondeti@codeaurora.org, juri.lelli@redhat.com,
edubezval@gmail.com, srinivas.pandruvada@linux.intel.com,
currojerez@riseup.net, javi.merino@kernel.org,
quentin.perret@arm.com
Subject: [PATCH v8 06/15] sched/topology: Lowest CPU asymmetry sched_domain level pointer
Date: Tue, 16 Oct 2018 11:15:04 +0100 [thread overview]
Message-ID: <20181016101513.26919-7-quentin.perret@arm.com> (raw)
In-Reply-To: <20181016101513.26919-1-quentin.perret@arm.com>
Add another member to the family of per-cpu sched_domain shortcut
pointers. This one, sd_asym_cpucapacity, points to the lowest level
at which the SD_ASYM_CPUCAPACITY flag is set. While at it, rename the
sd_asym shortcut to sd_asym_packing to avoid confusions.
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_asym_cpucapacity shortcut will
be used at first as the lowest domain where Energy-Aware Scheduling
(EAS) should be applied. For example, it is possible to apply EAS within
a socket on a multi-socket system, as long as each socket has an
asymmetric topology. Energy-aware cross-sockets wake-up balancing can
only happen if 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/fair.c | 2 +-
kernel/sched/sched.h | 3 ++-
kernel/sched/topology.c | 8 ++++++--
3 files changed, 9 insertions(+), 4 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index d59307ecd67d..e60858745071 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -9221,7 +9221,7 @@ static void nohz_balancer_kick(struct rq *rq)
}
}
- sd = rcu_dereference(per_cpu(sd_asym, cpu));
+ sd = rcu_dereference(per_cpu(sd_asym_packing, cpu));
if (sd) {
for_each_cpu(i, sched_domain_span(sd)) {
if (i == cpu ||
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index e82c7d464dc1..dcf4ec24f719 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -1203,7 +1203,8 @@ DECLARE_PER_CPU(int, sd_llc_size);
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_asym_packing);
+DECLARE_PER_CPU(struct sched_domain *, sd_asym_cpucapacity);
extern struct static_key_false sched_asym_cpucapacity;
struct sched_group_capacity {
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index 9d17d0989e48..b5aa56437758 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -508,7 +508,8 @@ DEFINE_PER_CPU(int, sd_llc_size);
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_asym_packing);
+DEFINE_PER_CPU(struct sched_domain *, sd_asym_cpucapacity);
DEFINE_STATIC_KEY_FALSE(sched_asym_cpucapacity);
static void update_top_cache_domain(int cpu)
@@ -534,7 +535,10 @@ static void update_top_cache_domain(int cpu)
rcu_assign_pointer(per_cpu(sd_numa, cpu), sd);
sd = highest_flag_domain(cpu, SD_ASYM_PACKING);
- rcu_assign_pointer(per_cpu(sd_asym, cpu), sd);
+ rcu_assign_pointer(per_cpu(sd_asym_packing, cpu), sd);
+
+ sd = lowest_flag_domain(cpu, SD_ASYM_CPUCAPACITY);
+ rcu_assign_pointer(per_cpu(sd_asym_cpucapacity, cpu), sd);
}
/*
--
2.19.1
next prev parent reply other threads:[~2018-10-16 10:15 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-16 10:14 [PATCH v8 00/15] Energy Aware Scheduling Quentin Perret
2018-10-16 10:14 ` [PATCH v8 01/15] sched: Relocate arch_scale_cpu_capacity Quentin Perret
2018-10-16 10:15 ` [PATCH v8 02/15] sched/cpufreq: Prepare schedutil for Energy Aware Scheduling Quentin Perret
2018-10-16 10:15 ` [PATCH v8 03/15] PM: Introduce an Energy Model management framework Quentin Perret
2018-11-07 16:32 ` Vincent Guittot
2018-11-07 17:02 ` Quentin Perret
2018-11-07 18:02 ` Vincent Guittot
2018-10-16 10:15 ` [PATCH v8 04/15] PM / EM: Expose the Energy Model in sysfs Quentin Perret
2018-10-16 10:15 ` [PATCH v8 05/15] sched/topology: Reference the Energy Model of CPUs when available Quentin Perret
2018-10-16 10:15 ` Quentin Perret [this message]
2018-10-16 10:15 ` [PATCH v8 07/15] sched/topology: Disable EAS on inappropriate platforms Quentin Perret
2018-10-16 10:15 ` [PATCH v8 08/15] sched/topology: Make Energy Aware Scheduling depend on schedutil Quentin Perret
2018-10-16 10:15 ` [PATCH v8 09/15] sched: Introduce sched_energy_present static key Quentin Perret
2018-10-16 10:15 ` [PATCH v8 10/15] sched: Introduce a sysctl for Energy Aware Scheduling Quentin Perret
2018-10-16 12:50 ` Juri Lelli
2018-10-16 13:36 ` Quentin Perret
2018-10-16 13:46 ` Juri Lelli
2018-10-16 10:15 ` [PATCH v8 11/15] sched/fair: Clean-up update_sg_lb_stats parameters Quentin Perret
2018-10-16 10:15 ` [PATCH v8 12/15] sched: Add over-utilization/tipping point indicator Quentin Perret
2018-10-16 10:15 ` [PATCH v8 13/15] sched/fair: Introduce an energy estimation helper function Quentin Perret
2018-10-16 10:15 ` [PATCH v8 14/15] sched/fair: Select an energy-efficient CPU on task wake-up Quentin Perret
2018-10-16 10:15 ` [PATCH v8 15/15] OPTIONAL: cpufreq: dt: Register an Energy Model Quentin Perret
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