From f6a7bbbfe61cc34c4e443141d3eb110a80473d8c Mon Sep 17 00:00:00 2001 From: Namhyung Kim Date: Fri, 31 Mar 2023 13:29:44 -0700 Subject: perf bench: Add pmu-scan benchmark The pmu-scan benchmark will repeatedly scan the sysfs to get the available PMU information. $ ./perf bench internals pmu-scan # Running 'internals/pmu-scan' benchmark: Computing performance of sysfs PMU event scan for 100 times Average PMU scanning took: 6850.990 usec (+- 48.445 usec) Signed-off-by: Namhyung Kim Acked-by: Ian Rogers Tested-by: Arnaldo Carvalho de Melo Cc: Adrian Hunter Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Leo Yan Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20230331202949.810326-2-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/bench/Build | 1 + tools/perf/bench/bench.h | 1 + tools/perf/bench/pmu-scan.c | 184 ++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 186 insertions(+) create mode 100644 tools/perf/bench/pmu-scan.c (limited to 'tools/perf/bench') diff --git a/tools/perf/bench/Build b/tools/perf/bench/Build index 6b6155a8ad09..0f158dc8139b 100644 --- a/tools/perf/bench/Build +++ b/tools/perf/bench/Build @@ -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 diff --git a/tools/perf/bench/bench.h b/tools/perf/bench/bench.h index edfc25793cca..0d2b65976212 100644 --- a/tools/perf/bench/bench.h +++ b/tools/perf/bench/bench.h @@ -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 diff --git a/tools/perf/bench/pmu-scan.c b/tools/perf/bench/pmu-scan.c new file mode 100644 index 000000000000..f0f007843bb8 --- /dev/null +++ b/tools/perf/bench/pmu-scan.c @@ -0,0 +1,184 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Benchmark scanning sysfs files for PMU information. + * + * Copyright 2023 Google LLC. + */ +#include +#include "bench.h" +#include "util/debug.h" +#include "util/pmu.h" +#include "util/pmus.h" +#include "util/stat.h" +#include +#include +#include +#include + +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 ", + 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; +} -- cgit v1.2.3