summaryrefslogtreecommitdiffstats
path: root/tools/perf/util/stat.c
blob: 4014b709f956b96b86dab3526f3b35fec6d8c166 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
#include <math.h>
#include "stat.h"
#include "evsel.h"

void update_stats(struct stats *stats, u64 val)
{
	double delta;

	stats->n++;
	delta = val - stats->mean;
	stats->mean += delta / stats->n;
	stats->M2 += delta*(val - stats->mean);

	if (val > stats->max)
		stats->max = val;

	if (val < stats->min)
		stats->min = val;
}

double avg_stats(struct stats *stats)
{
	return stats->mean;
}

/*
 * http://en.wikipedia.org/wiki/Algorithms_for_calculating_variance
 *
 *       (\Sum n_i^2) - ((\Sum n_i)^2)/n
 * s^2 = -------------------------------
 *                  n - 1
 *
 * http://en.wikipedia.org/wiki/Stddev
 *
 * The std dev of the mean is related to the std dev by:
 *
 *             s
 * s_mean = -------
 *          sqrt(n)
 *
 */
double stddev_stats(struct stats *stats)
{
	double variance, variance_mean;

	if (stats->n < 2)
		return 0.0;

	variance = stats->M2 / (stats->n - 1);
	variance_mean = variance / stats->n;

	return sqrt(variance_mean);
}

double rel_stddev_stats(double stddev, double avg)
{
	double pct = 0.0;

	if (avg)
		pct = 100.0 * stddev/avg;

	return pct;
}

bool __perf_evsel_stat__is(struct perf_evsel *evsel,
			   enum perf_stat_evsel_id id)
{
	struct perf_stat *ps = evsel->priv;

	return ps->id == id;
}

#define ID(id, name) [PERF_STAT_EVSEL_ID__##id] = #name
static const char *id_str[PERF_STAT_EVSEL_ID__MAX] = {
	ID(NONE,		x),
	ID(CYCLES_IN_TX,	cpu/cycles-t/),
	ID(TRANSACTION_START,	cpu/tx-start/),
	ID(ELISION_START,	cpu/el-start/),
	ID(CYCLES_IN_TX_CP,	cpu/cycles-ct/),
};
#undef ID

void perf_stat_evsel_id_init(struct perf_evsel *evsel)
{
	struct perf_stat *ps = evsel->priv;
	int i;

	/* ps->id is 0 hence PERF_STAT_EVSEL_ID__NONE by default */

	for (i = 0; i < PERF_STAT_EVSEL_ID__MAX; i++) {
		if (!strcmp(perf_evsel__name(evsel), id_str[i])) {
			ps->id = i;
			break;
		}
	}
}

struct perf_counts *perf_counts__new(int ncpus)
{
	int size = sizeof(struct perf_counts) +
		   ncpus * sizeof(struct perf_counts_values);

	return zalloc(size);
}

void perf_counts__delete(struct perf_counts *counts)
{
	free(counts);
}

static void perf_counts__reset(struct perf_counts *counts, int ncpus)
{
	memset(counts, 0, (sizeof(*counts) +
	       (ncpus * sizeof(struct perf_counts_values))));
}

void perf_evsel__reset_counts(struct perf_evsel *evsel, int ncpus)
{
	perf_counts__reset(evsel->counts, ncpus);
}

int perf_evsel__alloc_counts(struct perf_evsel *evsel, int ncpus)
{
	evsel->counts = perf_counts__new(ncpus);
	return evsel->counts != NULL ? 0 : -ENOMEM;
}

void perf_evsel__free_counts(struct perf_evsel *evsel)
{
	perf_counts__delete(evsel->counts);
	evsel->counts = NULL;
}
OpenPOWER on IntegriCloud