>From b74a74f953f4c34818a58831b6eb468b42b17c62 Mon Sep 17 00:00:00 2001
From: Zhang Rui <rui.zh...@intel.com>
Date: Tue, 23 Apr 2019 16:26:50 +0800
Subject: [PATCH] perf/rapl: restart perf rapl counter after resume
After S3 suspend/resume, "perf stat -I 1000 -e power/energy-pkg/ -a"
reports an insane value for the very first sampling period after resume
as shown below.
19.278989977 2.16 Joules power/energy-pkg/
20.279373569 1.96 Joules power/energy-pkg/
21.279765481 2.09 Joules power/energy-pkg/
22.280305420 2.10 Joules power/energy-pkg/
25.504782277 4,294,966,686.01 Joules power/energy-pkg/
26.505114993 3.58 Joules power/energy-pkg/
27.505471758 1.66 Joules power/energy-pkg/
Fix this by resetting the counter right after resume.
Kan, Liang proposed the prototype patch and I reworked it to use syscore
ops.
Signed-off-by: Zhang Rui <rui.zh...@intel.com>
Signed-off-by: Kan Liang <kan.li...@linux.intel.com>
---
arch/x86/events/intel/rapl.c | 84 +++++++++++++++++++++++++++++++++++++++-----
1 file changed, 76 insertions(+), 8 deletions(-)
diff --git a/arch/x86/events/intel/rapl.c b/arch/x86/events/intel/rapl.c
index 26c03f5..6cff8fd 100644
--- a/arch/x86/events/intel/rapl.c
+++ b/arch/x86/events/intel/rapl.c
@@ -55,6 +55,7 @@
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/perf_event.h>
+#include <linux/syscore_ops.h>
#include <asm/cpu_device_id.h>
#include <asm/intel-family.h>
#include "../perf_event.h"
@@ -228,6 +229,32 @@ static u64 rapl_event_update(struct perf_event *event)
return new_raw_count;
}
+static void rapl_pmu_update_all(struct rapl_pmu *pmu)
+{
+ struct perf_event *event;
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&pmu->lock, flags);
+
+ list_for_each_entry(event, &pmu->active_list, active_entry)
+ rapl_event_update(event);
+
+ raw_spin_unlock_irqrestore(&pmu->lock, flags);
+}
+
+static void rapl_pmu_restart_all(struct rapl_pmu *pmu)
+{
+ struct perf_event *event;
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&pmu->lock, flags);
+
+ list_for_each_entry(event, &pmu->active_list, active_entry)
+ local64_set(&event->hw.prev_count, rapl_read_counter(event));
+
+ raw_spin_unlock_irqrestore(&pmu->lock, flags);
+}
+
static void rapl_start_hrtimer(struct rapl_pmu *pmu)
{
hrtimer_start(&pmu->hrtimer, pmu->timer_interval,
@@ -237,18 +264,11 @@ static void rapl_start_hrtimer(struct rapl_pmu *pmu)
static enum hrtimer_restart rapl_hrtimer_handle(struct hrtimer *hrtimer)
{
struct rapl_pmu *pmu = container_of(hrtimer, struct rapl_pmu, hrtimer);
- struct perf_event *event;
- unsigned long flags;
if (!pmu->n_active)
return HRTIMER_NORESTART;
- raw_spin_lock_irqsave(&pmu->lock, flags);
-
- list_for_each_entry(event, &pmu->active_list, active_entry)
- rapl_event_update(event);
-
- raw_spin_unlock_irqrestore(&pmu->lock, flags);
+ rapl_pmu_update_all(pmu);
hrtimer_forward_now(hrtimer, pmu->timer_interval);
@@ -698,6 +718,52 @@ static int __init init_rapl_pmus(void)
return 0;
}
+
+#ifdef CONFIG_PM
+
+static int perf_rapl_suspend(void)
+{
+ int i;
+
+ get_online_cpus();
+ for (i = 0; i < rapl_pmus->maxpkg; i++)
+ rapl_pmu_update_all(rapl_pmus->pmus[i]);
+ put_online_cpus();
+ return 0;
+}
+
+static void perf_rapl_resume(void)
+{
+ int i;
+
+ get_online_cpus();
+ for (i = 0; i < rapl_pmus->maxpkg; i++)
+ rapl_pmu_restart_all(rapl_pmus->pmus[i]);
+ put_online_cpus();
+}
+
+static struct syscore_ops perf_rapl_syscore_ops = {
+ .resume = perf_rapl_resume,
+ .suspend = perf_rapl_suspend,
+};
+
+static void perf_rapl_pm_register(void)
+{
+ register_syscore_ops(&perf_rapl_syscore_ops);
+}
+
+static void perf_rapl_pm_unregister(void)
+{
+ unregister_syscore_ops(&perf_rapl_syscore_ops);
+}
+
+#else
+
+static inline void perf_rapl_pm_register(void) { }
+static inline void perf_rapl_pm_unregister(void) { }
+
+#endif
+
#define X86_RAPL_MODEL_MATCH(model, init) \
{ X86_VENDOR_INTEL, 6, model, X86_FEATURE_ANY, (unsigned long)&init }
@@ -798,6 +864,7 @@ static int __init rapl_pmu_init(void)
apply_quirk = rapl_init->apply_quirk;
rapl_cntr_mask = rapl_init->cntr_mask;
rapl_pmu_events_group.attrs = rapl_init->attrs;
+ perf_rapl_pm_register();
ret = rapl_check_hw_unit(apply_quirk);
if (ret)
@@ -836,6 +903,7 @@ static void __exit intel_rapl_exit(void)
{
cpuhp_remove_state_nocalls(CPUHP_AP_PERF_X86_RAPL_ONLINE);
perf_pmu_unregister(&rapl_pmus->pmu);
+ perf_rapl_pm_unregister();
cleanup_rapl_pmus();
}
module_exit(intel_rapl_exit);
--
2.7.4
