Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753593AbcDTCjh (ORCPT ); Tue, 19 Apr 2016 22:39:37 -0400 Received: from mail-pf0-f180.google.com ([209.85.192.180]:35092 "EHLO mail-pf0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753476AbcDTCjf (ORCPT ); Tue, 19 Apr 2016 22:39:35 -0400 From: Steve Muckle X-Google-Original-From: Steve Muckle To: "Rafael J. Wysocki" , Viresh Kumar Cc: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, Peter Zijlstra , Ingo Molnar , Vincent Guittot , Morten Rasmussen , Dietmar Eggemann , Juri Lelli , Patrick Bellasi , Michael Turquette Subject: [RFC PATCH 3/4] intel_pstate: support scheduler cpufreq callbacks on remote CPUs Date: Tue, 19 Apr 2016 19:39:28 -0700 Message-Id: <1461119969-10371-3-git-send-email-smuckle@linaro.org> X-Mailer: git-send-email 2.4.10 In-Reply-To: <1461119969-10371-1-git-send-email-smuckle@linaro.org> References: <1461119969-10371-1-git-send-email-smuckle@linaro.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4558 Lines: 147 In preparation for the scheduler cpufreq callback happening on remote CPUs, add support for this in intel_pstate, which requires the callback run on the local CPU to be able to change the CPU frequency. Signed-off-by: Steve Muckle --- drivers/cpufreq/intel_pstate.c | 88 +++++++++++++++++++++++++++++++++++++++--- 1 file changed, 83 insertions(+), 5 deletions(-) diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index 6c7cff13f0ed..fa49d3944aa5 100644 --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -162,6 +162,9 @@ struct _pid { * struct cpudata - Per CPU instance data storage * @cpu: CPU number for this instance data * @update_util: CPUFreq utility callback information + * @irq_work: Data for passing remote callbacks to the target CPU + * @time: Timestamp of CPUFreq callback + * @ipi_in_progress: Whether a remote callback IPI is outstanding * @pstate: Stores P state limits for this CPU * @vid: Stores VID limits for this CPU * @pid: Stores PID parameters for this CPU @@ -179,6 +182,9 @@ struct cpudata { int cpu; struct update_util_data update_util; + struct irq_work irq_work; + u64 time; + bool ipi_in_progress; struct pstate_data pstate; struct vid_data vid; @@ -1173,20 +1179,88 @@ static inline void intel_pstate_adjust_busy_pstate(struct cpudata *cpu) get_avg_frequency(cpu)); } +static void _intel_pstate_update_util(struct cpudata *cpu, u64 time) +{ + bool sample_taken = intel_pstate_sample(cpu, time); + + if (sample_taken && !hwp_active) + intel_pstate_adjust_busy_pstate(cpu); +} + +#ifdef CONFIG_SMP +static void intel_pstate_update_util_remote(struct irq_work *irq_work) +{ + struct cpudata *cpu = container_of(irq_work, struct cpudata, irq_work); + s64 delta_ns = cpu->time - cpu->sample.time; + + /* + * A local update may have happened while the ipi + * was in progress so re-check the time. + */ + if (delta_ns < pid_params.sample_rate_ns) + return; + + _intel_pstate_update_util(cpu, cpu->time); + + cpu->ipi_in_progress = false; +} + static void intel_pstate_update_util(struct update_util_data *data, u64 time, unsigned long util, unsigned long max) { struct cpudata *cpu = container_of(data, struct cpudata, update_util); - u64 delta_ns = time - cpu->sample.time; + s64 delta_ns = time - cpu->sample.time; - if ((s64)delta_ns >= pid_params.sample_rate_ns) { - bool sample_taken = intel_pstate_sample(cpu, time); + if (delta_ns < pid_params.sample_rate_ns) + return; - if (sample_taken && !hwp_active) - intel_pstate_adjust_busy_pstate(cpu); + if (cpu->cpu == smp_processor_id()) { + _intel_pstate_update_util(cpu, time); + } else { + /* The target CPU's rq lock is held. */ + if (cpu->ipi_in_progress) + return; + + /* Re-check sample_time which may have advanced. */ + smp_rmb(); + delta_ns = time - READ_ONCE(cpu->sample.time); + if (delta_ns < pid_params.sample_rate_ns) + return; + + cpu->ipi_in_progress = true; + cpu->time = time; + irq_work_queue_on(&cpu->irq_work, cpu->cpu); } } +static inline void intel_pstate_irq_work_sync(unsigned int cpu) +{ + irq_work_sync(&all_cpu_data[cpu]->irq_work); +} + +static inline void intel_pstate_init_irq_work(struct cpudata *cpu) +{ + init_irq_work(&cpu->irq_work, intel_pstate_update_util_remote); +} +#else /* !CONFIG_SMP */ +static inline void intel_pstate_irq_work_sync(unsigned int cpu) {} +static inline void intel_pstate_init_irq_work(struct cpudata *cpu) {} + +static void intel_pstate_update_util(struct update_util_data *data, u64 time, + unsigned long util, unsigned long max) +{ + struct cpudata *cpu = container_of(data, struct cpudata, update_util); + s64 delta_ns = time - cpu->sample.time; + + if (delta_ns < pid_params.sample_rate_ns) + return; + + _intel_pstate_update_util(cpu, time); +} +#endif + + + #define ICPU(model, policy) \ { X86_VENDOR_INTEL, 6, model, X86_FEATURE_APERFMPERF,\ (unsigned long)&policy } @@ -1273,6 +1347,7 @@ static void intel_pstate_clear_update_util_hook(unsigned int cpu) { cpufreq_remove_update_util_hook(cpu); synchronize_sched(); + intel_pstate_irq_work_sync(cpu); } static void intel_pstate_set_performance_limits(struct perf_limits *limits) @@ -1379,6 +1454,9 @@ static int intel_pstate_cpu_init(struct cpufreq_policy *policy) cpu = all_cpu_data[policy->cpu]; + intel_pstate_init_irq_work(cpu); + + if (limits->min_perf_pct == 100 && limits->max_perf_pct == 100) policy->policy = CPUFREQ_POLICY_PERFORMANCE; else -- 2.4.10