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#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;
}
}
}
void perf_evsel__reset_counts(struct perf_evsel *evsel, int ncpus)
{
memset(evsel->counts, 0, (sizeof(*evsel->counts) +
(ncpus * sizeof(struct perf_counts_values))));
}
int perf_evsel__alloc_counts(struct perf_evsel *evsel, int ncpus)
{
evsel->counts = zalloc((sizeof(*evsel->counts) +
(ncpus * sizeof(struct perf_counts_values))));
return evsel->counts != NULL ? 0 : -ENOMEM;
}
void perf_evsel__free_counts(struct perf_evsel *evsel)
{
zfree(&evsel->counts);
}
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