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Message-Id: <1461119969-10371-3-git-send-email-smuckle@linaro.org>
Date: Tue, 19 Apr 2016 19:39:28 -0700
From: Steve Muckle <steve.muckle@...aro.org>
To: "Rafael J. Wysocki" <rafael@...nel.org>,
Viresh Kumar <viresh.kumar@...aro.org>
Cc: linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...hat.com>,
Vincent Guittot <vincent.guittot@...aro.org>,
Morten Rasmussen <morten.rasmussen@....com>,
Dietmar Eggemann <dietmar.eggemann@....com>,
Juri Lelli <Juri.Lelli@....com>,
Patrick Bellasi <patrick.bellasi@....com>,
Michael Turquette <mturquette@...libre.com>
Subject: [RFC PATCH 3/4] intel_pstate: support scheduler cpufreq callbacks on remote CPUs
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 <smuckle@...aro.org>
---
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
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