@@ -15,6 +15,7 @@ perf-y += find-bit-bench.o
perf-y += inject-buildid.o
perf-y += evlist-open-close.o
perf-y += breakpoint.o
+perf-y += pmu-scan.o
perf-$(CONFIG_X86_64) += mem-memcpy-x86-64-asm.o
perf-$(CONFIG_X86_64) += mem-memset-x86-64-asm.o
@@ -42,6 +42,7 @@ int bench_inject_build_id(int argc, const char **argv);
int bench_evlist_open_close(int argc, const char **argv);
int bench_breakpoint_thread(int argc, const char **argv);
int bench_breakpoint_enable(int argc, const char **argv);
+int bench_pmu_scan(int argc, const char **argv);
#define BENCH_FORMAT_DEFAULT_STR "default"
#define BENCH_FORMAT_DEFAULT 0
new file mode 100644
@@ -0,0 +1,184 @@
+// 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;
+};
+
+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;
+ struct list_head *list;
+ struct pmu_scan_result *r;
+
+ perf_pmu__scan(NULL);
+
+ perf_pmus__for_each_pmu(pmu) {
+ 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->nr_caps = pmu->nr_caps;
+
+ r->nr_aliases = 0;
+ list_for_each(list, &pmu->aliases)
+ r->nr_aliases++;
+
+ 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_pmu__destroy();
+ return 0;
+}
+
+static int check_result(void)
+{
+ 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];
+ pmu = perf_pmu__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 = 0;
+ list_for_each(list, &pmu->aliases)
+ nr++;
+ 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;
+ unsigned int i;
+ 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 (i = 0; i < iterations; i++) {
+ gettimeofday(&start, NULL);
+ perf_pmu__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();
+ perf_pmu__destroy();
+ if (ret < 0)
+ break;
+ }
+
+ time_average = avg_stats(&stats);
+ time_stddev = stddev_stats(&stats);
+ pr_info(" Average PMU scanning took: %.3f usec (+- %.3f usec)\n",
+ 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;
+}
@@ -92,6 +92,7 @@ static struct bench internals_benchmarks[] = {
{ "kallsyms-parse", "Benchmark kallsyms parsing", bench_kallsyms_parse },
{ "inject-build-id", "Benchmark build-id injection", bench_inject_build_id },
{ "evlist-open-close", "Benchmark evlist open and close", bench_evlist_open_close },
+ { "pmu-scan", "Benchmark sysfs PMU info scanning", bench_pmu_scan },
{ NULL, NULL, NULL }
};