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[71.119.96.202]) by mx.google.com with ESMTPSA id i191sm7408793ioe.0.2015.05.11.19.14.27 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Mon, 11 May 2015 19:14:29 -0700 (PDT) From: Michael Turquette To: peterz@infradead.org, mingo@kernel.org Cc: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, preeti@linux.vnet.ibm.com, Morten.Rasmussen@arm.com, riel@redhat.com, efault@gmx.de, nicolas.pitre@linaro.org, daniel.lezcano@linaro.org, dietmar.eggemann@arm.com, vincent.guittot@linaro.org, amit.kucheria@linaro.org, juri.lelli@arm.com, rjw@rjwysocki.net, viresh.kumar@linaro.org, ashwin.chaugule@linaro.org, alex.shi@linaro.org, abelvesa@gmail.com, Russell King , Morten Rasmussen Subject: [PATCH RFC v2 1/4] arm: Frequency invariant scheduler load-tracking support Date: Mon, 11 May 2015 19:13:12 -0700 Message-Id: <1431396795-32439-2-git-send-email-mturquette@linaro.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1431396795-32439-1-git-send-email-mturquette@linaro.org> References: <1431396795-32439-1-git-send-email-mturquette@linaro.org> Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Morten Rasmussen Implements arch-specific function to provide the scheduler with a frequency scaling correction factor for more accurate load-tracking. The factor is: current_freq(cpu) << SCHED_CAPACITY_SHIFT / max_freq(cpu) This implementation only provides frequency invariance. No micro-architecture invariance yet. Cc: Russell King Signed-off-by: Morten Rasmussen --- Changes in v2: none arch/arm/include/asm/topology.h | 7 ++++++ arch/arm/kernel/smp.c | 53 +++++++++++++++++++++++++++++++++++++++-- arch/arm/kernel/topology.c | 17 +++++++++++++ 3 files changed, 75 insertions(+), 2 deletions(-) diff --git a/arch/arm/include/asm/topology.h b/arch/arm/include/asm/topology.h index 2fe85ff..4b985dc 100644 --- a/arch/arm/include/asm/topology.h +++ b/arch/arm/include/asm/topology.h @@ -24,6 +24,13 @@ void init_cpu_topology(void); void store_cpu_topology(unsigned int cpuid); const struct cpumask *cpu_coregroup_mask(int cpu); +#define arch_scale_freq_capacity arm_arch_scale_freq_capacity +struct sched_domain; +extern +unsigned long arm_arch_scale_freq_capacity(struct sched_domain *sd, int cpu); + +DECLARE_PER_CPU(atomic_long_t, cpu_freq_capacity); + #else static inline void init_cpu_topology(void) { } diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index 86ef244..297ce1b 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -672,12 +672,34 @@ static DEFINE_PER_CPU(unsigned long, l_p_j_ref); static DEFINE_PER_CPU(unsigned long, l_p_j_ref_freq); static unsigned long global_l_p_j_ref; static unsigned long global_l_p_j_ref_freq; +static DEFINE_PER_CPU(atomic_long_t, cpu_max_freq); +DEFINE_PER_CPU(atomic_long_t, cpu_freq_capacity); + +/* + * Scheduler load-tracking scale-invariance + * + * Provides the scheduler with a scale-invariance correction factor that + * compensates for frequency scaling through arch_scale_freq_capacity() + * (implemented in topology.c). + */ +static inline +void scale_freq_capacity(int cpu, unsigned long curr, unsigned long max) +{ + unsigned long capacity; + + if (!max) + return; + + capacity = (curr << SCHED_CAPACITY_SHIFT) / max; + atomic_long_set(&per_cpu(cpu_freq_capacity, cpu), capacity); +} static int cpufreq_callback(struct notifier_block *nb, unsigned long val, void *data) { struct cpufreq_freqs *freq = data; int cpu = freq->cpu; + unsigned long max = atomic_long_read(&per_cpu(cpu_max_freq, cpu)); if (freq->flags & CPUFREQ_CONST_LOOPS) return NOTIFY_OK; @@ -702,6 +724,9 @@ static int cpufreq_callback(struct notifier_block *nb, per_cpu(l_p_j_ref_freq, cpu), freq->new); } + + scale_freq_capacity(cpu, freq->new, max); + return NOTIFY_OK; } @@ -709,11 +734,35 @@ static struct notifier_block cpufreq_notifier = { .notifier_call = cpufreq_callback, }; +static int cpufreq_policy_callback(struct notifier_block *nb, + unsigned long val, void *data) +{ + struct cpufreq_policy *policy = data; + int i; + + for_each_cpu(i, policy->cpus) { + scale_freq_capacity(i, policy->cur, policy->max); + atomic_long_set(&per_cpu(cpu_max_freq, i), policy->max); + } + + return NOTIFY_OK; +} + +static struct notifier_block cpufreq_policy_notifier = { + .notifier_call = cpufreq_policy_callback, +}; + static int __init register_cpufreq_notifier(void) { - return cpufreq_register_notifier(&cpufreq_notifier, + int ret; + + ret = cpufreq_register_notifier(&cpufreq_notifier, CPUFREQ_TRANSITION_NOTIFIER); + if (ret) + return ret; + + return cpufreq_register_notifier(&cpufreq_policy_notifier, + CPUFREQ_POLICY_NOTIFIER); } core_initcall(register_cpufreq_notifier); - #endif diff --git a/arch/arm/kernel/topology.c b/arch/arm/kernel/topology.c index 08b7847..9c09e6e 100644 --- a/arch/arm/kernel/topology.c +++ b/arch/arm/kernel/topology.c @@ -169,6 +169,23 @@ static void update_cpu_capacity(unsigned int cpu) cpu, arch_scale_cpu_capacity(NULL, cpu)); } +/* + * Scheduler load-tracking scale-invariance + * + * Provides the scheduler with a scale-invariance correction factor that + * compensates for frequency scaling (arch_scale_freq_capacity()). The scaling + * factor is updated in smp.c + */ +unsigned long arm_arch_scale_freq_capacity(struct sched_domain *sd, int cpu) +{ + unsigned long curr = atomic_long_read(&per_cpu(cpu_freq_capacity, cpu)); + + if (!curr) + return SCHED_CAPACITY_SCALE; + + return curr; +} + #else static inline void parse_dt_topology(void) {} static inline void update_cpu_capacity(unsigned int cpuid) {}