Quelle  evlist-open-close.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0
#include <inttypes.h>
#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 inline u64 timeval2usec(struct timeval *tv)
{
 return tv->tv_sec * USEC_PER_SEC + tv->tv_usec;
}

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 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 * perf_cpu_map__nr(evsel->core.cpus);

 return cnt;
}

static struct evlist *bench__create_evlist(char *evstr, const char *uid_str)
{
 struct parse_events_error err;
 struct evlist *evlist = evlist__new();
 int ret;

 if (!evlist) {
  pr_err("Not enough memory to create evlist\n");
  return NULL;
 }

 parse_events_error__init(&err);
 ret = parse_events(evlist, evstr, &err);
 if (ret) {
  parse_events_error__print(&err, evstr);
  parse_events_error__exit(&err);
  pr_err("Run 'perf list' for a list of valid events\n");
  ret = 1;
  goto out_delete_evlist;
 }
 parse_events_error__exit(&err);
 if (uid_str) {
  uid_t uid = parse_uid(uid_str);

  if (uid == UINT_MAX) {
   pr_err("Invalid User: %s", uid_str);
   ret = -EINVAL;
   goto out_delete_evlist;
  }
  ret = parse_uid_filter(evlist, uid);
  if (ret)
   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)
{
 char sbuf[STRERR_BUFSIZE];
 int 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, const char *uid_str)
{
 // used to print statistics only
 struct evlist *evlist = bench__create_evlist(evstr, uid_str);
 double time_average, time_stddev;
 struct timeval start, end, diff;
 struct stats time_stats;
 u64 runtime_us;
 int i, err;

 if (!evlist)
  return -ENOMEM;

 init_stats(&time_stats);

 printf(" Number of cpus:\t%d\n", perf_cpu_map__nr(evlist->core.user_requested_cpus));
 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, uid_str);
  if (!evlist)
   return -ENOMEM;

  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 = timeval2usec(&diff);
  update_stats(&time_stats, runtime_us);

  evlist__delete(evlist);
  pr_debug("Iteration %d took:\t%" PRIu64 "us\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)
{
 char sbuf[STRERR_BUFSIZE];
 struct strbuf buf;
 int i, 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)
{
 const char *uid_str = NULL;
 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", &uid_str, "user", "user to profile"),
  OPT_BOOLEAN(0, "per-thread", &opts.target.per_thread, "use per-thread mmaps"),
  OPT_END()
 };
 const char *const bench_usage[] = {
  "perf bench internals evlist-open-close ",
  NULL
 };
 char *evstr, errbuf[BUFSIZ];
 int err;

 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, sizeof(errbuf));
  pr_err("%s\n", errbuf);
  goto out;
 }

 /* Enable ignoring missing threads when -p option is defined. */
 opts.ignore_missing_thread = 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, uid_str);

 free(evstr);
out:
 return err;
}