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[209.132.180.67]) by mx.google.com with ESMTP id vt4si63402718pab.8.2016.01.08.06.10.04; Fri, 08 Jan 2016 06:10:04 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-pm-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-pm-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-pm-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755265AbcAHOJu (ORCPT + 11 others); Fri, 8 Jan 2016 09:09:50 -0500 Received: from foss.arm.com ([217.140.101.70]:45523 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755505AbcAHOJs (ORCPT ); Fri, 8 Jan 2016 09:09:48 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B3C1446A; Fri, 8 Jan 2016 06:09:14 -0800 (PST) Received: from e106622-lin.cambridge.arm.com (e106622-lin.cambridge.arm.com [10.1.208.152]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 5EE153F459; Fri, 8 Jan 2016 06:09:45 -0800 (PST) From: Juri Lelli To: linux-kernel@vger.kernel.org Cc: linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, peterz@infradead.org, vincent.guittot@linaro.org, robh+dt@kernel.org, mark.rutland@arm.com, linux@arm.linux.org.uk, sudeep.holla@arm.com, lorenzo.pieralisi@arm.com, catalin.marinas@arm.com, will.deacon@arm.com, morten.rasmussen@arm.com, dietmar.eggemann@arm.com, juri.lelli@arm.com, broonie@kernel.org, "Rafael J. Wysocki" , Viresh Kumar Subject: [RFC PATCH v2 2/4] drivers/cpufreq: implement init_cpu_capacity_default() Date: Fri, 8 Jan 2016 14:09:30 +0000 Message-Id: <1452262172-31861-3-git-send-email-juri.lelli@arm.com> X-Mailer: git-send-email 2.2.2 In-Reply-To: <1452262172-31861-1-git-send-email-juri.lelli@arm.com> References: <1452262172-31861-1-git-send-email-juri.lelli@arm.com> Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org To get default values for CPUs capacity we profile a simple (bogus) integer benchmark on such CPUs; then we normalize results to 1024 (highest capacity in the system). Architectures that want this during boot have to register a cpufreq driver callback and call this function from there (as we require cpufreq to be up and running). Cc: Russell King Cc: Catalin Marinas Cc: Will Deacon Cc: "Rafael J. Wysocki" Cc: Viresh Kumar Cc: Vincent Guittot Cc: Sudeep Holla Cc: Mark Rutland Signed-off-by: Juri Lelli --- arch/arm/kernel/topology.c | 2 +- arch/arm64/kernel/topology.c | 12 +++ drivers/cpufreq/Makefile | 2 +- drivers/cpufreq/cpufreq.c | 1 + drivers/cpufreq/cpufreq_capacity.c | 161 +++++++++++++++++++++++++++++++++++++ include/linux/cpufreq.h | 2 + 6 files changed, 178 insertions(+), 2 deletions(-) create mode 100644 drivers/cpufreq/cpufreq_capacity.c -- 2.2.2 -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/arch/arm/kernel/topology.c b/arch/arm/kernel/topology.c index ec279d1..c9c87a5 100644 --- a/arch/arm/kernel/topology.c +++ b/arch/arm/kernel/topology.c @@ -47,7 +47,7 @@ unsigned long arch_scale_cpu_capacity(struct sched_domain *sd, int cpu) return per_cpu(cpu_scale, cpu); } -static void set_capacity_scale(unsigned int cpu, unsigned long capacity) +void set_capacity_scale(unsigned int cpu, unsigned long capacity) { per_cpu(cpu_scale, cpu) = capacity; } diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c index 694f6de..3b75d63 100644 --- a/arch/arm64/kernel/topology.c +++ b/arch/arm64/kernel/topology.c @@ -23,6 +23,18 @@ #include #include +static DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE; + +unsigned long arm_arch_scale_cpu_capacity(struct sched_domain *sd, int cpu) +{ + return per_cpu(cpu_scale, cpu); +} + +void set_capacity_scale(unsigned int cpu, unsigned long capacity) +{ + per_cpu(cpu_scale, cpu) = capacity; +} + static int __init get_cpu_for_node(struct device_node *node) { struct device_node *cpu_node; diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile index c0af1a1..ca47aea 100644 --- a/drivers/cpufreq/Makefile +++ b/drivers/cpufreq/Makefile @@ -1,5 +1,5 @@ # CPUfreq core -obj-$(CONFIG_CPU_FREQ) += cpufreq.o freq_table.o +obj-$(CONFIG_CPU_FREQ) += cpufreq.o freq_table.o cpufreq_capacity.o # CPUfreq stats obj-$(CONFIG_CPU_FREQ_STAT) += cpufreq_stats.o diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 8412ce5..8720228 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -2452,6 +2452,7 @@ int cpufreq_register_driver(struct cpufreq_driver *driver_data) } register_hotcpu_notifier(&cpufreq_cpu_notifier); + cpufreq_init_cpu_capacity(); pr_debug("driver %s up and running\n", driver_data->name); out: diff --git a/drivers/cpufreq/cpufreq_capacity.c b/drivers/cpufreq/cpufreq_capacity.c new file mode 100644 index 0000000..2fd5248 --- /dev/null +++ b/drivers/cpufreq/cpufreq_capacity.c @@ -0,0 +1,161 @@ +/* + * Default CPU capacity calculation for u-arch invariance + * + * Copyright (C) 2015 ARM Ltd. + * Juri Lelli + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed "as is" WITHOUT ANY WARRANTY of any + * kind, whether express or implied; without even the implied warranty + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ +#include +#include + +static unsigned long long elapsed[NR_CPUS]; + +/* + * Don't let compiler optimize following two functions; + * otherwise we might loose u-arch differences. + * Also, my_int_sqrt is cut-and-paste from lib/int_sqrt.c. + */ +static unsigned long __attribute__((optimize("O0"))) +my_int_sqrt(unsigned long x) +{ + unsigned long b, m, y = 0; + + if (x <= 1) + return x; + + m = 1UL << (BITS_PER_LONG - 2); + while (m != 0) { + b = y + m; + y >>= 1; + + if (x >= b) { + x -= b; + y += m; + } + m >>= 2; + } + + return y; +} + +static unsigned long __attribute__((optimize("O0"))) +bogus_bench(void) +{ + unsigned long i, res; + + for (i = 0; i < 100000; i++) + res = my_int_sqrt(i); + + return res; +} + +static int run_bogus_benchmark(int cpu) +{ + int ret, trials = 25; + u64 begin, end, diff, diff_avg = 0, count = 0; + unsigned long res; + + ret = set_cpus_allowed_ptr(current, cpumask_of(cpu)); + if (ret) { + pr_warn("%s: failed to set allowed ptr\n", __func__); + return -EINVAL; + } + + while (trials--) { + begin = local_clock(); + res = bogus_bench(); + end = local_clock(); + diff = end - begin; + diff_avg = diff_avg * count + diff; + diff_avg = div64_u64(diff_avg, ++count); + pr_debug("%s: cpu=%d begin=%llu end=%llu" + " diff=%llu diff_avg=%llu count=%llu res=%lu\n", + __func__, cpu, begin, end, diff, + diff_avg, count, res); + } + elapsed[cpu] = diff_avg; + + ret = set_cpus_allowed_ptr(current, cpu_active_mask); + if (ret) { + pr_warn("%s: failed to set allowed ptr\n", __func__); + return -EINVAL; + } + + return 0; +} + +bool __weak arch_wants_init_cpu_capacity(void) +{ + return false; +} + +void __weak set_capacity_scale(int cpu, unsigned long capacity) { } + +void cpufreq_init_cpu_capacity(void) +{ + int cpu, fcpu; + unsigned long long elapsed_min = ULLONG_MAX; + unsigned int curr_min, curr_max; + struct cpufreq_policy *policy; + + if (!arch_wants_init_cpu_capacity()) + return; + + for_each_possible_cpu(cpu) { + policy = cpufreq_cpu_get(cpu); + if (IS_ERR_OR_NULL(policy)) + return; + + /* + * We profile only first CPU of each frequency domain; + * and use that value as capacity of every CPU in the domain. + */ + fcpu = cpumask_first(policy->related_cpus); + if (cpu != fcpu) { + elapsed[cpu] = elapsed[fcpu]; + cpufreq_cpu_put(policy); + continue; + } + + down_write(&policy->rwsem); + curr_min = policy->user_policy.min; + curr_max = policy->user_policy.max; + policy->user_policy.min = policy->cpuinfo.max_freq; + policy->user_policy.max = policy->cpuinfo.max_freq; + up_write(&policy->rwsem); + cpufreq_cpu_put(policy); + cpufreq_update_policy(cpu); + + run_bogus_benchmark(cpu); + if (elapsed[cpu] < elapsed_min) + elapsed_min = elapsed[cpu]; + pr_debug("%s: cpu=%d elapsed=%llu (min=%llu)\n", + __func__, cpu, elapsed[cpu], elapsed_min); + + policy = cpufreq_cpu_get(cpu); + down_write(&policy->rwsem); + policy->user_policy.min = curr_min; + policy->user_policy.max = curr_max; + up_write(&policy->rwsem); + cpufreq_cpu_put(policy); + cpufreq_update_policy(cpu); + } + + for_each_possible_cpu(cpu) { + unsigned long capacity; + + capacity = div64_u64((elapsed_min << 10), elapsed[cpu]); + pr_debug("%s: CPU%d capacity=%lu\n", __func__, cpu, capacity); + set_capacity_scale(cpu, capacity); + } + + pr_info("dynamic CPUs capacity installed\n"); +} diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h index 177c768..968be47 100644 --- a/include/linux/cpufreq.h +++ b/include/linux/cpufreq.h @@ -420,6 +420,8 @@ static inline unsigned long cpufreq_scale(unsigned long old, u_int div, #endif } +void cpufreq_init_cpu_capacity(void); + /********************************************************************* * CPUFREQ GOVERNORS * *********************************************************************/