// SPDX-License-Identifier: GPL-2.0
/*
* Benchmark synthesis of perf events such as at the start of a 'perf
* record'. Synthesis is done on the current process and the 'dummy' event
* handlers are invoked that support dump_trace but otherwise do nothing.
*
* Copyright 2019 Google LLC.
*/
#include <stdio.h>
#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 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_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 bench_usage[] = {
"perf bench internals synthesize <options>",
NULL
};
static atomic_t event_count;
static int process_synthesized_event(const 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 time_average, time_stddev, event_average, event_stddev;
int err;
struct stats time_stats, event_stats;
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,
true, 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));
}
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;
}
static int run_single_threaded(void)
{
struct perf_session *session;
struct target target = {
.pid = "self",
};
struct perf_thread_map *threads;
int err;
perf_set_singlethreaded();
session = perf_session__new(NULL, NULL);
if (IS_ERR(session)) {
pr_err("Session creation failed.\n");
return PTR_ERR(session);
}
threads = thread_map__new_by_pid(getpid());
if (!threads) {
pr_err("Thread map creation failed.\n");
err = -ENOMEM;
goto err_out;
}
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_run_single_threaded(session, threads, &target, true);
err_out:
if (threads)
perf_thread_map__put(threads);
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, NULL);
if (IS_ERR(session))
return PTR_ERR(session);
atomic_set(&event_count, 0);
gettimeofday(&start, NULL);
err = __machine__synthesize_threads(&session->machines.host,
NULL,
target, NULL,
process_synthesized_event,
true, 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;
}
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