[RFC PATCH v1 02/11] cpuidle: attach cpuidle governor statistics to the per-CPU device

Aubrey Li
2017-07-10T01:48:57Z

From: Aubrey Li <aubrey.li@linux.intel.com>

A generic CPU idle governor is required to make the prediction of
how long the coming idle. The statistic data taken from the existing
menu governor is attached to the per-CPU device data structure
---
include/linux/cpuidle.h | 30 ++++++++++++++++++++++++++++++
1 file changed, 30 insertions(+)

diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
index fc1e5d7..f17a53b 100644
--- a/include/linux/cpuidle.h
+++ b/include/linux/cpuidle.h
@@ -61,6 +61,34 @@ struct cpuidle_state {
int index);
};

+/*
+ * Please note when changing the tuning values:
+ * If (MAX_INTERESTING-1) * RESOLUTION > UINT_MAX, the result of
+ * a scaling operation multiplication may overflow on 32 bit platforms.
+ * In that case, #define RESOLUTION as ULL to get 64 bit result:
+ * #define RESOLUTION 1024ULL
+ *
+ * The default values do not overflow.
+ */
+#define BUCKETS 12
+#define INTERVAL_SHIFT 3
+#define INTERVALS (1UL << INTERVAL_SHIFT)
+#define RESOLUTION 1024
+#define DECAY 8
+#define MAX_INTERESTING 50000
+
+struct cpuidle_governor_stat {
+ int last_state_idx;
+
+ unsigned int next_timer_us;
+ unsigned int predicted_us;
+ unsigned int bucket;
+ unsigned int correction_factor[BUCKETS];
+ unsigned int intervals[INTERVALS];
+ int interval_ptr;
+};
+
+
/* Idle State Flags */
#define CPUIDLE_FLAG_NONE (0x00)
#define CPUIDLE_FLAG_COUPLED (0x02) /* state applies to multiple cpus */
@@ -89,8 +117,10 @@ struct cpuidle_device {
cpumask_t coupled_cpus;
struct cpuidle_coupled *coupled;
#endif
+ struct cpuidle_governor_stat gov_stat;
};

+
DECLARE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
DECLARE_PER_CPU(struct cpuidle_device, cpuidle_dev);

--
2.7.4