linux/tools/perf/util/stat.h

#ifndef __PERF_STATS_H
#define __PERF_STATS_H

#include <linux/types.h>

struct stats
{
	double n, mean, M2;
	u64 max, min;
};

enum perf_stat_evsel_id {
	PERF_STAT_EVSEL_ID__NONE = 0,
	PERF_STAT_EVSEL_ID__MAX,
};

struct perf_stat {
	struct stats		res_stats[3];
	enum perf_stat_evsel_id	id;
};

void update_stats(struct stats *stats, u64 val);
double avg_stats(struct stats *stats);
double stddev_stats(struct stats *stats);
double rel_stddev_stats(double stddev, double avg);

static inline void init_stats(struct stats *stats)
{
	stats->n    = 0.0;
	stats->mean = 0.0;
	stats->M2   = 0.0;
	stats->min  = (u64) -1;
	stats->max  = 0;
}

struct perf_evsel;
bool __perf_evsel_stat__is(struct perf_evsel *evsel,
			   enum perf_stat_evsel_id id);

#define perf_stat_evsel__is(evsel, id) \
	__perf_evsel_stat__is(evsel, PERF_STAT_EVSEL_ID__ ## id)

void perf_stat_evsel_id_init(struct perf_evsel *evsel);

#endif