Quelle  kallsyms-parse.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0
/*
 * Benchmark of /proc/kallsyms parsing.
 *
 * Copyright 2020 Google LLC.
 */
#include <stdlib.h>
#include "bench.h"
#include "../util/stat.h"
#include <linux/time64.h>
#include <subcmd/parse-options.h>
#include <symbol/kallsyms.h>

static unsigned int iterations = 100;

static const struct option options[] = {
 OPT_UINTEGER('i', "iterations", &iterations,
  "Number of iterations used to compute average"),
 OPT_END()
};

static const char *const bench_usage[] = {
 "perf bench internals kallsyms-parse ",
 NULL
};

static int bench_process_symbol(void *arg __maybe_unused,
    const char *name __maybe_unused,
    char type __maybe_unused,
    u64 start __maybe_unused)
{
 return 0;
}

static int do_kallsyms_parse(void)
{
 struct timeval start, end, diff;
 u64 runtime_us;
 unsigned int i;
 double time_average, time_stddev;
 int err;
 struct stats time_stats;

 init_stats(&time_stats);

 for (i = 0; i < iterations; i++) {
  gettimeofday(&start, NULL);
  err = kallsyms__parse("/proc/kallsyms", NULL,
    bench_process_symbol);
  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);
 }

 time_average = avg_stats(&time_stats) / USEC_PER_MSEC;
 time_stddev = stddev_stats(&time_stats) / USEC_PER_MSEC;
 printf(" Average kallsyms__parse took: %.3f ms (+- %.3f ms)\n",
  time_average, time_stddev);
 return 0;
}

int bench_kallsyms_parse(int argc, const char **argv)
{
 argc = parse_options(argc, argv, options, bench_usage, 0);
 if (argc) {
  usage_with_options(bench_usage, options);
  exit(EXIT_FAILURE);
 }

 return do_kallsyms_parse();
}