[PATCH] perf bench: add benchmark for evlist open/close operations

From: Riccardo Mancini
Date: Mon Aug 09 2021 - 16:12:17 EST


This new benchmark finds the total time that is taken to open, mmap,
enable, disable, munmap, close an evlist (time taken for new,
create_maps, config, delete is not counted in).
The evlist can be configured as in perf-record using the
-a,-C,-e,-u,--per-thread,-t,-p options.
The events can be duplicated in the evlist to quickly test performance
with many events using the -n options.
Furthermore, also the number of iterations used to calculate the
statistics is customizable.

Examples:
- Open one dummy event system-wide:
$ sudo ./perf bench internals evlist-open-close
Number of cpus: 4
Number of threads: 1
Number of events: 1 (4 fds)
Number of iterations: 100
Average open-close took: 613.870 usec (+- 32.852 usec)

- Open the group '{cs,cycles}' on CPU 0
$ sudo ./perf bench internals evlist-open-close -e '{cs,cycles}' -C 0
Number of cpus: 1
Number of threads: 1
Number of events: 2 (2 fds)
Number of iterations: 100
Average open-close took: 8503.220 usec (+- 252.652 usec)

- Open 10 'cycles' events for user 0, calculate average over 100 runs
$ sudo ./perf bench internals evlist-open-close -e cycles -n 10 -u 0 -i 100
Number of cpus: 4
Number of threads: 328
Number of events: 10 (13120 fds)
Number of iterations: 100
Average open-close took: 180043.140 usec (+- 2295.889 usec)

Signed-off-by: Riccardo Mancini <rickyman7@xxxxxxxxx>
---
tools/perf/bench/Build | 1 +
tools/perf/bench/bench.h | 1 +
tools/perf/bench/evlist-open-close.c | 275 +++++++++++++++++++++++++++
tools/perf/builtin-bench.c | 1 +
4 files changed, 278 insertions(+)
create mode 100644 tools/perf/bench/evlist-open-close.c

diff --git a/tools/perf/bench/Build b/tools/perf/bench/Build
index e43f46931b41b78f..61d45fcb4057c945 100644
--- a/tools/perf/bench/Build
+++ b/tools/perf/bench/Build
@@ -13,6 +13,7 @@ perf-y += synthesize.o
perf-y += kallsyms-parse.o
perf-y += find-bit-bench.o
perf-y += inject-buildid.o
+perf-y += evlist-open-close.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 eac36afab2b39fa5..b3480bc33fe84885 100644
--- a/tools/perf/bench/bench.h
+++ b/tools/perf/bench/bench.h
@@ -48,6 +48,7 @@ int bench_epoll_ctl(int argc, const char **argv);
int bench_synthesize(int argc, const char **argv);
int bench_kallsyms_parse(int argc, const char **argv);
int bench_inject_build_id(int argc, const char **argv);
+int bench_evlist_open_close(int argc, const char **argv);

#define BENCH_FORMAT_DEFAULT_STR "default"
#define BENCH_FORMAT_DEFAULT 0
diff --git a/tools/perf/bench/evlist-open-close.c b/tools/perf/bench/evlist-open-close.c
new file mode 100644
index 0000000000000000..40bce06f5ca7bef3
--- /dev/null
+++ b/tools/perf/bench/evlist-open-close.c
@@ -0,0 +1,275 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <stdio.h>
+#include <stdlib.h>
+#include <limits.h>
+#include "bench.h"
+#include "../util/debug.h"
+#include "../util/stat.h"
+#include "../util/evlist.h"
+#include "../util/evsel.h"
+#include "../util/strbuf.h"
+#include "../util/record.h"
+#include "../util/parse-events.h"
+#include "internal/threadmap.h"
+#include "internal/cpumap.h"
+#include <linux/perf_event.h>
+#include <linux/kernel.h>
+#include <linux/time64.h>
+#include <linux/string.h>
+#include <subcmd/parse-options.h>
+
+#define MMAP_FLUSH_DEFAULT 1
+
+static int iterations = 100;
+static int nr_events = 1;
+static const char *event_string = "dummy";
+
+static struct record_opts opts = {
+ .sample_time = true,
+ .mmap_pages = UINT_MAX,
+ .user_freq = UINT_MAX,
+ .user_interval = ULLONG_MAX,
+ .freq = 4000,
+ .target = {
+ .uses_mmap = true,
+ .default_per_cpu = true,
+ },
+ .mmap_flush = MMAP_FLUSH_DEFAULT,
+ .nr_threads_synthesize = 1,
+ .ctl_fd = -1,
+ .ctl_fd_ack = -1,
+};
+
+static const struct option options[] = {
+ OPT_STRING('e', "event", &event_string, "event",
+ "event selector. use 'perf list' to list available events"),
+ OPT_INTEGER('n', "nr-events", &nr_events,
+ "number of dummy events to create (default 1). If used with -e, it clones those events n times (1 = no change)"),
+ OPT_INTEGER('i', "iterations", &iterations,
+ "Number of iterations used to compute average (default=100)"),
+ OPT_BOOLEAN('a', "all-cpus", &opts.target.system_wide,
+ "system-wide collection from all CPUs"),
+ OPT_STRING('C', "cpu", &opts.target.cpu_list, "cpu",
+ "list of cpus where to open events"),
+ OPT_STRING('p', "pid", &opts.target.pid, "pid",
+ "record events on existing process id"),
+ OPT_STRING('t', "tid", &opts.target.tid, "tid",
+ "record events on existing thread id"),
+ OPT_STRING('u', "uid", &opts.target.uid_str, "user",
+ "user to profile"),
+ OPT_BOOLEAN(0, "per-thread", &opts.target.per_thread,
+ "use per-thread mmaps"),
+ OPT_END()
+};
+
+static const char *const bench_usage[] = {
+ "perf bench internals evlist-open-close <options>",
+ NULL
+};
+
+static int evlist__count_evsel_fds(struct evlist *evlist)
+{
+ struct evsel *evsel;
+ int cnt = 0;
+
+ evlist__for_each_entry(evlist, evsel) {
+ cnt += evsel->core.threads->nr * evsel->core.cpus->nr;
+ }
+
+ return cnt;
+}
+
+static struct evlist *bench__create_evlist(char *evstr)
+{
+ struct evlist *evlist;
+ struct parse_events_error err;
+ int ret;
+
+ evlist = evlist__new();
+ if (!evlist) {
+ pr_err("Not enough memory to create evlist\n");
+ return NULL;
+ }
+
+ bzero(&err, sizeof(err));
+ ret = parse_events(evlist, evstr, &err);
+ if (ret) {
+ parse_events_print_error(&err, evstr);
+ pr_err("Run 'perf list' for a list of valid events\n");
+ ret = 1;
+ goto out_delete_evlist;
+ }
+
+ ret = evlist__create_maps(evlist, &opts.target);
+ if (ret < 0) {
+ pr_err("Not enough memory to create thread/cpu maps\n");
+ goto out_delete_evlist;
+ }
+
+ evlist__config(evlist, &opts, NULL);
+
+ return evlist;
+
+out_delete_evlist:
+ evlist__delete(evlist);
+ return NULL;
+}
+
+static int bench__do_evlist_open_close(struct evlist *evlist)
+{
+ int err = -1;
+ char sbuf[STRERR_BUFSIZE];
+
+ err = evlist__open(evlist);
+ if (err < 0) {
+ pr_err("evlist__open: %s\n",
+ str_error_r(errno, sbuf, sizeof(sbuf)));
+ return err;
+ }
+
+ err = evlist__mmap(evlist, opts.mmap_pages);
+ if (err < 0) {
+ pr_err("evlist__mmap: %s\n",
+ str_error_r(errno, sbuf, sizeof(sbuf)));
+ return err;
+ }
+
+ evlist__enable(evlist);
+
+ evlist__disable(evlist);
+ evlist__munmap(evlist);
+ evlist__close(evlist);
+
+ return 0;
+}
+
+static int bench_evlist_open_close__run(char *evstr)
+{
+ struct evlist *evlist;
+ struct timeval start, end, diff;
+ double time_average, time_stddev;
+ int i;
+ int err;
+ u64 runtime_us;
+ struct stats time_stats;
+
+ init_stats(&time_stats);
+
+ // used to print statistics only
+ evlist = bench__create_evlist(evstr);
+
+ printf(" Number of cpus:\t%d\n", evlist->core.cpus->nr);
+ printf(" Number of threads:\t%d\n", evlist->core.threads->nr);
+ printf(" Number of events:\t%d (%d fds)\n",
+ evlist->core.nr_entries, evlist__count_evsel_fds(evlist));
+ printf(" Number of iterations:\t%d\n", iterations);
+
+ evlist__delete(evlist);
+
+ for (i = 0; i < iterations; i++) {
+ pr_debug("Started iteration %d\n", i);
+ evlist = bench__create_evlist(evstr);
+ gettimeofday(&start, NULL);
+ err = bench__do_evlist_open_close(evlist);
+ if (err) {
+ evlist__delete(evlist);
+ return err;
+ }
+
+ gettimeofday(&end, NULL);
+ timersub(&end, &start, &diff);
+ runtime_us = diff.tv_sec * USEC_PER_SEC + diff.tv_usec;
+ update_stats(&time_stats, runtime_us);
+
+ evlist__delete(evlist);
+ pr_debug("Iteration %d took:\t%ldus\n", i, runtime_us);
+ }
+
+ time_average = avg_stats(&time_stats);
+ time_stddev = stddev_stats(&time_stats);
+ printf(" Average open-close took: %.3f usec (+- %.3f usec)\n",
+ time_average, time_stddev);
+
+ return 0;
+}
+
+static char *bench__repeat_event_string(const char *evstr, int n)
+{
+ int err, i, final_size, str_size;
+ struct strbuf buf;
+ char sbuf[STRERR_BUFSIZE];
+
+ str_size = strlen(evstr);
+ final_size = str_size * n + n;
+
+ err = strbuf_init(&buf, final_size);
+ if (err) {
+ pr_err("strbuf_init: %s\n",
+ str_error_r(err, sbuf, sizeof(sbuf)));
+ goto out_error;
+ }
+
+ for (i = 0; i < n; i++) {
+ err = strbuf_add(&buf, evstr, str_size);
+ if (err) {
+ pr_err("strbuf_add: %s\n",
+ str_error_r(err, sbuf, sizeof(sbuf)));
+ goto out_error;
+ }
+
+ err = strbuf_addch(&buf, i == n-1 ? '\0' : ',');
+ if (err) {
+ pr_err("strbuf_addch: %s\n",
+ str_error_r(err, sbuf, sizeof(sbuf)));
+ goto out_error;
+ }
+ }
+
+ return strbuf_detach(&buf, NULL);
+
+out_error:
+ strbuf_release(&buf);
+ return NULL;
+}
+
+
+int bench_evlist_open_close(int argc, const char **argv)
+{
+ int err = 0;
+ char *evstr, errbuf[BUFSIZ];
+
+ argc = parse_options(argc, argv, options, bench_usage, 0);
+ if (argc) {
+ usage_with_options(bench_usage, options);
+ exit(EXIT_FAILURE);
+ }
+
+ err = target__validate(&opts.target);
+ if (err) {
+ target__strerror(&opts.target, err, errbuf, BUFSIZ);
+ pr_err("%s\n", errbuf);
+ goto out;
+ }
+
+ err = target__parse_uid(&opts.target);
+ if (err) {
+ target__strerror(&opts.target, err, errbuf, BUFSIZ);
+ pr_err("%s", errbuf);
+ goto out;
+ }
+
+ /* Enable ignoring missing threads when -u/-p option is defined. */
+ opts.ignore_missing_thread = opts.target.uid != UINT_MAX || opts.target.pid;
+
+ evstr = bench__repeat_event_string(event_string, nr_events);
+ if (!evstr) {
+ err = -ENOMEM;
+ goto out;
+ }
+
+ err = bench_evlist_open_close__run(evstr);
+
+ free(evstr);
+out:
+ return err;
+}
diff --git a/tools/perf/builtin-bench.c b/tools/perf/builtin-bench.c
index 62a7b7420a448517..d0895162c2ba6411 100644
--- a/tools/perf/builtin-bench.c
+++ b/tools/perf/builtin-bench.c
@@ -88,6 +88,7 @@ static struct bench internals_benchmarks[] = {
{ "synthesize", "Benchmark perf event synthesis", bench_synthesize },
{ "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 },
{ NULL, NULL, NULL }
};

--
2.31.1