diff options
Diffstat (limited to 'tools/perf/bench/pmu-scan.c')
| -rw-r--r-- | tools/perf/bench/pmu-scan.c | 186 |
1 files changed, 186 insertions, 0 deletions
diff --git a/tools/perf/bench/pmu-scan.c b/tools/perf/bench/pmu-scan.c new file mode 100644 index 0000000000..9e4d36486f --- /dev/null +++ b/tools/perf/bench/pmu-scan.c @@ -0,0 +1,186 @@ +// 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; +} |