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Subject[PATCH v5 1/3] perf bench: add a multi-threaded synthesize benchmark
From
By default this isn't run as it reads /proc and may not have access.
For consistency, modify the single threaded benchmark to compute an
average time per event.

Signed-off-by: Ian Rogers <irogers@google.com>
---
tools/perf/bench/synthesize.c | 211 ++++++++++++++++++++++++++++++----
1 file changed, 186 insertions(+), 25 deletions(-)

diff --git a/tools/perf/bench/synthesize.c b/tools/perf/bench/synthesize.c
index 6291257bc9c9..8d624aea1c5e 100644
--- a/tools/perf/bench/synthesize.c
+++ b/tools/perf/bench/synthesize.c
@@ -10,60 +10,105 @@
#include "bench.h"
#include "../util/debug.h"
#include "../util/session.h"
+#include "../util/stat.h"
#include "../util/synthetic-events.h"
#include "../util/target.h"
#include "../util/thread_map.h"
#include "../util/tool.h"
+#include "../util/util.h"
+#include <linux/atomic.h>
#include <linux/err.h>
#include <linux/time64.h>
#include <subcmd/parse-options.h>

-static unsigned int iterations = 10000;
+static unsigned int min_threads = 1;
+static unsigned int max_threads = UINT_MAX;
+static unsigned int single_iterations = 10000;
+static unsigned int multi_iterations = 10;
+static bool run_st;
+static bool run_mt;

static const struct option options[] = {
- OPT_UINTEGER('i', "iterations", &iterations,
- "Number of iterations used to compute average"),
+ OPT_BOOLEAN('s', "st", &run_st, "Run single threaded benchmark"),
+ OPT_BOOLEAN('t', "mt", &run_mt, "Run multi-threaded benchmark"),
+ OPT_UINTEGER('m', "min-threads", &min_threads,
+ "Minimum number of threads in multithreaded bench"),
+ OPT_UINTEGER('M', "max-threads", &max_threads,
+ "Maximum number of threads in multithreaded bench"),
+ OPT_UINTEGER('i', "single-iterations", &single_iterations,
+ "Number of iterations used to compute single-threaded average"),
+ OPT_UINTEGER('I', "multi-iterations", &multi_iterations,
+ "Number of iterations used to compute multi-threaded average"),
OPT_END()
};

-static const char *const usage[] = {
+static const char *const bench_usage[] = {
"perf bench internals synthesize <options>",
NULL
};

+static atomic_t event_count;

-static int do_synthesize(struct perf_session *session,
- struct perf_thread_map *threads,
- struct target *target, bool data_mmap)
+static int process_synthesized_event(struct perf_tool *tool __maybe_unused,
+ union perf_event *event __maybe_unused,
+ struct perf_sample *sample __maybe_unused,
+ struct machine *machine __maybe_unused)
+{
+ atomic_inc(&event_count);
+ return 0;
+}
+
+static int do_run_single_threaded(struct perf_session *session,
+ struct perf_thread_map *threads,
+ struct target *target, bool data_mmap)
{
const unsigned int nr_threads_synthesize = 1;
struct timeval start, end, diff;
u64 runtime_us;
unsigned int i;
- double average;
+ double time_average, time_stddev, event_average, event_stddev;
int err;
+ struct stats time_stats, event_stats;

- gettimeofday(&start, NULL);
- for (i = 0; i < iterations; i++) {
- err = machine__synthesize_threads(&session->machines.host,
- target, threads, data_mmap,
+ init_stats(&time_stats);
+ init_stats(&event_stats);
+
+ for (i = 0; i < single_iterations; i++) {
+ atomic_set(&event_count, 0);
+ gettimeofday(&start, NULL);
+ err = __machine__synthesize_threads(&session->machines.host,
+ NULL,
+ target, threads,
+ process_synthesized_event,
+ data_mmap,
nr_threads_synthesize);
if (err)
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);
+ update_stats(&event_stats, atomic_read(&event_count));
}

- gettimeofday(&end, NULL);
- timersub(&end, &start, &diff);
- runtime_us = diff.tv_sec * USEC_PER_SEC + diff.tv_usec;
- average = (double)runtime_us/(double)iterations;
- printf("Average %ssynthesis took: %f usec\n",
- data_mmap ? "data " : "", average);
+ time_average = avg_stats(&time_stats);
+ time_stddev = stddev_stats(&time_stats);
+ printf(" Average %ssynthesis took: %.3f usec (+- %.3f usec)\n",
+ data_mmap ? "data " : "", time_average, time_stddev);
+
+ event_average = avg_stats(&event_stats);
+ event_stddev = stddev_stats(&event_stats);
+ printf(" Average num. events: %.3f (+- %.3f)\n",
+ event_average, event_stddev);
+
+ printf(" Average time per event %.3f usec\n",
+ time_average / event_average);
return 0;
}

-int bench_synthesize(int argc, const char **argv)
+static int run_single_threaded(void)
{
- struct perf_tool tool;
struct perf_session *session;
struct target target = {
.pid = "self",
@@ -71,8 +116,7 @@ int bench_synthesize(int argc, const char **argv)
struct perf_thread_map *threads;
int err;

- argc = parse_options(argc, argv, options, usage, 0);
-
+ perf_set_singlethreaded();
session = perf_session__new(NULL, false, NULL);
if (IS_ERR(session)) {
pr_err("Session creation failed.\n");
@@ -84,13 +128,16 @@ int bench_synthesize(int argc, const char **argv)
err = -ENOMEM;
goto err_out;
}
- perf_tool__fill_defaults(&tool);

- err = do_synthesize(session, threads, &target, false);
+ puts(
+"Computing performance of single threaded perf event synthesis by\n"
+"synthesizing events on the perf process itself:");
+
+ err = do_run_single_threaded(session, threads, &target, false);
if (err)
goto err_out;

- err = do_synthesize(session, threads, &target, true);
+ err = do_run_single_threaded(session, threads, &target, true);

err_out:
if (threads)
@@ -99,3 +146,117 @@ int bench_synthesize(int argc, const char **argv)
perf_session__delete(session);
return err;
}
+
+static int do_run_multi_threaded(struct target *target,
+ unsigned int nr_threads_synthesize)
+{
+ struct timeval start, end, diff;
+ u64 runtime_us;
+ unsigned int i;
+ double time_average, time_stddev, event_average, event_stddev;
+ int err;
+ struct stats time_stats, event_stats;
+ struct perf_session *session;
+
+ init_stats(&time_stats);
+ init_stats(&event_stats);
+ for (i = 0; i < multi_iterations; i++) {
+ session = perf_session__new(NULL, false, NULL);
+ if (!session)
+ return -ENOMEM;
+
+ atomic_set(&event_count, 0);
+ gettimeofday(&start, NULL);
+ err = __machine__synthesize_threads(&session->machines.host,
+ NULL,
+ target, NULL,
+ process_synthesized_event,
+ false,
+ nr_threads_synthesize);
+ if (err) {
+ perf_session__delete(session);
+ 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);
+ update_stats(&event_stats, atomic_read(&event_count));
+ perf_session__delete(session);
+ }
+
+ time_average = avg_stats(&time_stats);
+ time_stddev = stddev_stats(&time_stats);
+ printf(" Average synthesis took: %.3f usec (+- %.3f usec)\n",
+ time_average, time_stddev);
+
+ event_average = avg_stats(&event_stats);
+ event_stddev = stddev_stats(&event_stats);
+ printf(" Average num. events: %.3f (+- %.3f)\n",
+ event_average, event_stddev);
+
+ printf(" Average time per event %.3f usec\n",
+ time_average / event_average);
+ return 0;
+}
+
+static int run_multi_threaded(void)
+{
+ struct target target = {
+ .cpu_list = "0"
+ };
+ unsigned int nr_threads_synthesize;
+ int err;
+
+ if (max_threads == UINT_MAX)
+ max_threads = sysconf(_SC_NPROCESSORS_ONLN);
+
+ puts(
+"Computing performance of multi threaded perf event synthesis by\n"
+"synthesizing events on CPU 0:");
+
+ for (nr_threads_synthesize = min_threads;
+ nr_threads_synthesize <= max_threads;
+ nr_threads_synthesize++) {
+ if (nr_threads_synthesize == 1)
+ perf_set_singlethreaded();
+ else
+ perf_set_multithreaded();
+
+ printf(" Number of synthesis threads: %u\n",
+ nr_threads_synthesize);
+
+ err = do_run_multi_threaded(&target, nr_threads_synthesize);
+ if (err)
+ return err;
+ }
+ perf_set_singlethreaded();
+ return 0;
+}
+
+int bench_synthesize(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);
+ }
+
+ /*
+ * If neither single threaded or multi-threaded are specified, default
+ * to running just single threaded.
+ */
+ if (!run_st && !run_mt)
+ run_st = true;
+
+ if (run_st)
+ err = run_single_threaded();
+
+ if (!err && run_mt)
+ err = run_multi_threaded();
+
+ return err;
+}
--
2.26.0.110.g2183baf09c-goog
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