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Date:   Mon, 9 Aug 2021 17:23:31 -0300
From:   Arnaldo Carvalho de Melo <acme@kernel.org>
To:     Riccardo Mancini <rickyman7@gmail.com>
Cc:     Ian Rogers <irogers@google.com>,
        Namhyung Kim <namhyung@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Jiri Olsa <jolsa@redhat.com>, linux-kernel@vger.kernel.org,
        linux-perf-users@vger.kernel.org
Subject: Re: [PATCH] perf bench: add benchmark for evlist open/close
 operations
Message-ID: <YRGOwx3xlPRxNAXM@kernel.org>
References: <20210809201101.277594-1-rickyman7@gmail.com>
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Em Mon, Aug 09, 2021 at 10:11:02PM +0200, Riccardo Mancini escreveu:
> 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@gmail.com>
> ---
>  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));

man bzero

       The bzero() function is deprecated (marked as LEGACY in POSIX.1-2001); use memset(3) in new programs.  POSIX.1-2008 removes the specification of bzero().  The bzero() function first appeared in 4.3BSD.
       
I'm replacing it with a memset().

> +	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
> 

-- 

- Arnaldo