From mboxrd@z Thu Jan 1 00:00:00 1970 From: Morten Rasmussen Subject: [RFCv2 PATCH 15/23] sched, cpufreq: Introduce current cpu compute capacity into scheduler Date: Thu, 3 Jul 2014 17:26:02 +0100 Message-ID: <1404404770-323-16-git-send-email-morten.rasmussen@arm.com> References: <1404404770-323-1-git-send-email-morten.rasmussen@arm.com> Content-Type: text/plain; charset=WINDOWS-1252 Content-Transfer-Encoding: quoted-printable Return-path: Received: from service87.mimecast.com ([91.220.42.44]:45695 "EHLO service87.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759340AbaGCQ0U (ORCPT ); Thu, 3 Jul 2014 12:26:20 -0400 In-Reply-To: <1404404770-323-1-git-send-email-morten.rasmussen@arm.com> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, peterz@infradead.org, mingo@kernel.org Cc: rjw@rjwysocki.net, vincent.guittot@linaro.org, daniel.lezcano@linaro.org, preeti@linux.vnet.ibm.com, Dietmar.Eggemann@arm.com, pjt@google.com The scheduler is currently unaware of frequency changes and the current compute capacity offered by the cpus. This patch is not the solution. It is a hack to give us something to experiment with for now. A proper solution could be based on the frequency invariant load tracking proposed in the past: https://lkml.org/lkml/2013/4/16/289 The best way to get current compute capacity is likely to be architecture specific. A potential solution is therefore to let the architecture implement get_curr_capacity() instead. This patch should _not_ be considered safe. Signed-off-by: Morten Rasmussen --- drivers/cpufreq/cpufreq.c | 2 ++ include/linux/sched.h | 2 ++ kernel/sched/fair.c | 11 +++++++++++ kernel/sched/sched.h | 2 ++ 4 files changed, 17 insertions(+) diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index abda660..a2b788d 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -28,6 +28,7 @@ #include #include #include +#include #include =20 /** @@ -315,6 +316,7 @@ static void __cpufreq_notify_transition(struct cpufreq_= policy *policy, =09=09pr_debug("FREQ: %lu - CPU: %lu\n", =09=09=09 (unsigned long)freqs->new, (unsigned long)freqs->cpu); =09=09trace_cpu_frequency(freqs->new, freqs->cpu); +=09=09set_curr_capacity(freqs->cpu, (freqs->new*1024)/policy->max); =09=09srcu_notifier_call_chain(&cpufreq_transition_notifier_list, =09=09=09=09CPUFREQ_POSTCHANGE, freqs); =09=09if (likely(policy) && likely(policy->cpu =3D=3D freqs->cpu)) diff --git a/include/linux/sched.h b/include/linux/sched.h index e5d8d57..faebd87 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -3025,4 +3025,6 @@ static inline unsigned long rlimit_max(unsigned int l= imit) =09return task_rlimit_max(current, limit); } =20 +void set_curr_capacity(int cpu, long capacity); + #endif diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 37e9ea1..9720f04 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -7564,9 +7564,20 @@ void init_cfs_rq(struct cfs_rq *cfs_rq) =09atomic64_set(&cfs_rq->decay_counter, 1); =09atomic_long_set(&cfs_rq->removed_load, 0); =09atomic_long_set(&cfs_rq->uw_removed_load, 0); +=09atomic_long_set(&cfs_rq->curr_capacity, 1024); #endif } =20 +void set_curr_capacity(int cpu, long capacity) +{ +=09atomic_long_set(&cpu_rq(cpu)->cfs.curr_capacity, capacity); +} + +static inline unsigned long get_curr_capacity(int cpu) +{ +=09return atomic_long_read(&cpu_rq(cpu)->cfs.curr_capacity); +} + #ifdef CONFIG_FAIR_GROUP_SCHED static void task_move_group_fair(struct task_struct *p, int on_rq) { diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 455d152..a6d5239 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -342,6 +342,8 @@ struct cfs_rq { =09u64 last_decay; =09atomic_long_t removed_load, uw_removed_load; =20 +=09atomic_long_t curr_capacity; + #ifdef CONFIG_FAIR_GROUP_SCHED =09/* Required to track per-cpu representation of a task_group */ =09u32 tg_runnable_contrib; --=20 1.7.9.5