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// SPDX-License-Identifier: GPL-2.0
/*
* Benchmark scanning sysfs files for PMU information.
*
* Copyright 2023 Google LLC.
*/
#include <stdio.h>
#include "bench.h"
#include "util/debug.h"
#include "util/pmu.h"
#include "util/pmus.h"
#include "util/stat.h"
#include <linux/atomic.h>
#include <linux/err.h>
#include <linux/time64.h>
#include <subcmd/parse-options.h>
static unsigned int iterations = 100;
struct pmu_scan_result {
char *name;
int nr_aliases;
int nr_formats;
int nr_caps;
bool is_core;
};
static const struct option options[] = {
OPT_UINTEGER('i', "iterations", &iterations,
"Number of iterations used to compute average"),
OPT_END()
};
static const char *const bench_usage[] = {
"perf bench internals pmu-scan <options>",
NULL
};
static int nr_pmus;
static struct pmu_scan_result *results;
static int save_result(void)
{
struct perf_pmu *pmu = NULL;
struct list_head *list;
struct pmu_scan_result *r;
while ((pmu = perf_pmus__scan(pmu)) != NULL) {
r = realloc(results, (nr_pmus + 1) * sizeof(*r));
if (r == NULL)
return -ENOMEM;
results = r;
r = results + nr_pmus;
r->name = strdup(pmu->name);
r->is_core = pmu->is_core;
r->nr_caps = pmu->nr_caps;
r->nr_aliases = perf_pmu__num_events(pmu);
r->nr_formats = 0;
list_for_each(list, &pmu->format)
r->nr_formats++;
pr_debug("pmu[%d] name=%s, nr_caps=%d, nr_aliases=%d, nr_formats=%d\n",
nr_pmus, r->name, r->nr_caps, r->nr_aliases, r->nr_formats);
nr_pmus++;
}
perf_pmus__destroy();
return 0;
}
static int check_result(bool core_only)
{
struct pmu_scan_result *r;
struct perf_pmu *pmu;
struct list_head *list;
int nr;
for (int i = 0; i < nr_pmus; i++) {
r = &results[i];
if (core_only && !r->is_core)
continue;
pmu = perf_pmus__find(r->name);
if (pmu == NULL) {
pr_err("Cannot find PMU %s\n", r->name);
return -1;
}
if (pmu->nr_caps != (u32)r->nr_caps) {
pr_err("Unmatched number of event caps in %s: expect %d vs got %d\n",
pmu->name, r->nr_caps, pmu->nr_caps);
return -1;
}
nr = perf_pmu__num_events(pmu);
if (nr != r->nr_aliases) {
pr_err("Unmatched number of event aliases in %s: expect %d vs got %d\n",
pmu->name, r->nr_aliases, nr);
return -1;
}
nr = 0;
list_for_each(list, &pmu->format)
nr++;
if (nr != r->nr_formats) {
pr_err("Unmatched number of event formats in %s: expect %d vs got %d\n",
pmu->name, r->nr_formats, nr);
return -1;
}
}
return 0;
}
static void delete_result(void)
{
for (int i = 0; i < nr_pmus; i++)
free(results[i].name);
free(results);
results = NULL;
nr_pmus = 0;
}
static int run_pmu_scan(void)
{
struct stats stats;
struct timeval start, end, diff;
double time_average, time_stddev;
u64 runtime_us;
int ret;
init_stats(&stats);
pr_info("Computing performance of sysfs PMU event scan for %u times\n",
iterations);
if (save_result() < 0) {
pr_err("Failed to initialize PMU scan result\n");
return -1;
}
for (int j = 0; j < 2; j++) {
bool core_only = (j == 0);
for (unsigned int i = 0; i < iterations; i++) {
gettimeofday(&start, NULL);
if (core_only)
perf_pmus__scan_core(NULL);
else
perf_pmus__scan(NULL);
gettimeofday(&end, NULL);
timersub(&end, &start, &diff);
runtime_us = diff.tv_sec * USEC_PER_SEC + diff.tv_usec;
update_stats(&stats, runtime_us);
ret = check_result(core_only);
perf_pmus__destroy();
if (ret < 0)
break;
}
time_average = avg_stats(&stats);
time_stddev = stddev_stats(&stats);
pr_info(" Average%s PMU scanning took: %.3f usec (+- %.3f usec)\n",
core_only ? " core" : "", time_average, time_stddev);
}
delete_result();
return 0;
}
int bench_pmu_scan(int argc, const char **argv)
{
int err = 0;
argc = parse_options(argc, argv, options, bench_usage, 0);
if (argc) {
usage_with_options(bench_usage, options);
exit(EXIT_FAILURE);
}
err = run_pmu_scan();
return err;
}
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