1 // SPDX-License-Identifier: GPL-2.0
3 * Benchmark scanning sysfs files for PMU information.
5 * Copyright 2023 Google LLC.
9 #include "util/debug.h"
11 #include "util/pmus.h"
12 #include "util/stat.h"
13 #include <linux/atomic.h>
14 #include <linux/err.h>
15 #include <linux/time64.h>
16 #include <subcmd/parse-options.h>
18 static unsigned int iterations = 100;
20 struct pmu_scan_result {
28 static const struct option options[] = {
29 OPT_UINTEGER('i', "iterations", &iterations,
30 "Number of iterations used to compute average"),
34 static const char *const bench_usage[] = {
35 "perf bench internals pmu-scan <options>",
40 static struct pmu_scan_result *results;
42 static int save_result(void)
44 struct perf_pmu *pmu = NULL;
45 struct list_head *list;
46 struct pmu_scan_result *r;
48 while ((pmu = perf_pmus__scan(pmu)) != NULL) {
49 r = realloc(results, (nr_pmus + 1) * sizeof(*r));
54 r = results + nr_pmus;
56 r->name = strdup(pmu->name);
57 r->is_core = pmu->is_core;
58 r->nr_caps = pmu->nr_caps;
60 r->nr_aliases = perf_pmu__num_events(pmu);
63 list_for_each(list, &pmu->format)
66 pr_debug("pmu[%d] name=%s, nr_caps=%d, nr_aliases=%d, nr_formats=%d\n",
67 nr_pmus, r->name, r->nr_caps, r->nr_aliases, r->nr_formats);
75 static int check_result(bool core_only)
77 struct pmu_scan_result *r;
79 struct list_head *list;
82 for (int i = 0; i < nr_pmus; i++) {
84 if (core_only && !r->is_core)
87 pmu = perf_pmus__find(r->name);
89 pr_err("Cannot find PMU %s\n", r->name);
93 if (pmu->nr_caps != (u32)r->nr_caps) {
94 pr_err("Unmatched number of event caps in %s: expect %d vs got %d\n",
95 pmu->name, r->nr_caps, pmu->nr_caps);
99 nr = perf_pmu__num_events(pmu);
100 if (nr != r->nr_aliases) {
101 pr_err("Unmatched number of event aliases in %s: expect %d vs got %d\n",
102 pmu->name, r->nr_aliases, nr);
107 list_for_each(list, &pmu->format)
109 if (nr != r->nr_formats) {
110 pr_err("Unmatched number of event formats in %s: expect %d vs got %d\n",
111 pmu->name, r->nr_formats, nr);
118 static void delete_result(void)
120 for (int i = 0; i < nr_pmus; i++)
121 free(results[i].name);
128 static int run_pmu_scan(void)
131 struct timeval start, end, diff;
132 double time_average, time_stddev;
137 pr_info("Computing performance of sysfs PMU event scan for %u times\n",
140 if (save_result() < 0) {
141 pr_err("Failed to initialize PMU scan result\n");
145 for (int j = 0; j < 2; j++) {
146 bool core_only = (j == 0);
148 for (unsigned int i = 0; i < iterations; i++) {
149 gettimeofday(&start, NULL);
151 perf_pmus__scan_core(NULL);
153 perf_pmus__scan(NULL);
154 gettimeofday(&end, NULL);
155 timersub(&end, &start, &diff);
156 runtime_us = diff.tv_sec * USEC_PER_SEC + diff.tv_usec;
157 update_stats(&stats, runtime_us);
159 ret = check_result(core_only);
160 perf_pmus__destroy();
164 time_average = avg_stats(&stats);
165 time_stddev = stddev_stats(&stats);
166 pr_info(" Average%s PMU scanning took: %.3f usec (+- %.3f usec)\n",
167 core_only ? " core" : "", time_average, time_stddev);
173 int bench_pmu_scan(int argc, const char **argv)
177 argc = parse_options(argc, argv, options, bench_usage, 0);
179 usage_with_options(bench_usage, options);
183 err = run_pmu_scan();