alistair23-linux/tools/perf/util/stat.c
Jiri Olsa e2f56da1d6 perf stat: Add id into perf_stat struct
We need fast way to identify evsel as transaction event for shadow
counters computation. Currently we are using possition (in evlist) based
way.

Adding 'id' into 'struct perf_stat' so it can carry transaction event ID
and we can use it for shadow counters computations.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/20150604135055.GB23625@krava.redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-06-08 10:30:30 -03:00

93 lines
1.6 KiB
C

#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),
};
#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;
}
}
}