libperf: Add counting example

Current libperf man pages mention file counting.c "coming with libperf package",
however, the file is missing. Add the file then.

Fixes: 81de3bf37a ("libperf: Add man pages")
Signed-off-by: Michael Petlan <mpetlan@redhat.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
LPU-Reference: 20200227194424.28210-1-mpetlan@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Michael Petlan 2020-02-27 20:44:24 +01:00 committed by Arnaldo Carvalho de Melo
parent dabce16bd2
commit 76ce02651d

View File

@ -0,0 +1,83 @@
#include <linux/perf_event.h>
#include <perf/evlist.h>
#include <perf/evsel.h>
#include <perf/cpumap.h>
#include <perf/threadmap.h>
#include <perf/mmap.h>
#include <perf/core.h>
#include <perf/event.h>
#include <stdio.h>
#include <unistd.h>
static int libperf_print(enum libperf_print_level level,
const char *fmt, va_list ap)
{
return vfprintf(stderr, fmt, ap);
}
int main(int argc, char **argv)
{
int count = 100000, err = 0;
struct perf_evlist *evlist;
struct perf_evsel *evsel;
struct perf_thread_map *threads;
struct perf_counts_values counts;
struct perf_event_attr attr1 = {
.type = PERF_TYPE_SOFTWARE,
.config = PERF_COUNT_SW_CPU_CLOCK,
.read_format = PERF_FORMAT_TOTAL_TIME_ENABLED|PERF_FORMAT_TOTAL_TIME_RUNNING,
.disabled = 1,
};
struct perf_event_attr attr2 = {
.type = PERF_TYPE_SOFTWARE,
.config = PERF_COUNT_SW_TASK_CLOCK,
.read_format = PERF_FORMAT_TOTAL_TIME_ENABLED|PERF_FORMAT_TOTAL_TIME_RUNNING,
.disabled = 1,
};
libperf_init(libperf_print);
threads = perf_thread_map__new_dummy();
if (!threads) {
fprintf(stderr, "failed to create threads\n");
return -1;
}
perf_thread_map__set_pid(threads, 0, 0);
evlist = perf_evlist__new();
if (!evlist) {
fprintf(stderr, "failed to create evlist\n");
goto out_threads;
}
evsel = perf_evsel__new(&attr1);
if (!evsel) {
fprintf(stderr, "failed to create evsel1\n");
goto out_evlist;
}
perf_evlist__add(evlist, evsel);
evsel = perf_evsel__new(&attr2);
if (!evsel) {
fprintf(stderr, "failed to create evsel2\n");
goto out_evlist;
}
perf_evlist__add(evlist, evsel);
perf_evlist__set_maps(evlist, NULL, threads);
err = perf_evlist__open(evlist);
if (err) {
fprintf(stderr, "failed to open evsel\n");
goto out_evlist;
}
perf_evlist__enable(evlist);
while (count--);
perf_evlist__disable(evlist);
perf_evlist__for_each_evsel(evlist, evsel) {
perf_evsel__read(evsel, 0, 0, &counts);
fprintf(stdout, "count %llu, enabled %llu, run %llu\n",
counts.val, counts.ena, counts.run);
}
perf_evlist__close(evlist);
out_evlist:
perf_evlist__delete(evlist);
out_threads:
perf_thread_map__put(threads);
return err;
}