Re: [PATCH v5 1/3] perf bench: add a multi-threaded synthesize benchmark

[Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>]

Em Tue, Apr 14, 2020 at 10:40:48PM -0700, Ian Rogers escreveu:
> 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.

Thanks, applied,

- Arnaldo
 
> 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
> 

-- 

- Arnaldo