1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Benchmark of /proc/kallsyms parsing.
4 *
5 * Copyright 2020 Google LLC.
6 */
7 #include <stdlib.h>
8 #include "bench.h"
9 #include "../util/stat.h"
10 #include <linux/time64.h>
11 #include <subcmd/parse-options.h>
12 #include <symbol/kallsyms.h>
13
14 static unsigned int iterations = 100;
15
16 static const struct option options[] = {
17 OPT_UINTEGER('i', "iterations", &iterations,
18 "Number of iterations used to compute average"),
19 OPT_END()
20 };
21
22 static const char *const bench_usage[] = {
23 "perf bench internals kallsyms-parse <options>",
24 NULL
25 };
26
bench_process_symbol(void * arg __maybe_unused,const char * name __maybe_unused,char type __maybe_unused,u64 start __maybe_unused)27 static int bench_process_symbol(void *arg __maybe_unused,
28 const char *name __maybe_unused,
29 char type __maybe_unused,
30 u64 start __maybe_unused)
31 {
32 return 0;
33 }
34
do_kallsyms_parse(void)35 static int do_kallsyms_parse(void)
36 {
37 struct timeval start, end, diff;
38 u64 runtime_us;
39 unsigned int i;
40 double time_average, time_stddev;
41 int err;
42 struct stats time_stats;
43
44 init_stats(&time_stats);
45
46 for (i = 0; i < iterations; i++) {
47 gettimeofday(&start, NULL);
48 err = kallsyms__parse("/proc/kallsyms", NULL,
49 bench_process_symbol);
50 if (err)
51 return err;
52
53 gettimeofday(&end, NULL);
54 timersub(&end, &start, &diff);
55 runtime_us = diff.tv_sec * USEC_PER_SEC + diff.tv_usec;
56 update_stats(&time_stats, runtime_us);
57 }
58
59 time_average = avg_stats(&time_stats) / USEC_PER_MSEC;
60 time_stddev = stddev_stats(&time_stats) / USEC_PER_MSEC;
61 printf(" Average kallsyms__parse took: %.3f ms (+- %.3f ms)\n",
62 time_average, time_stddev);
63 return 0;
64 }
65
bench_kallsyms_parse(int argc,const char ** argv)66 int bench_kallsyms_parse(int argc, const char **argv)
67 {
68 argc = parse_options(argc, argv, options, bench_usage, 0);
69 if (argc) {
70 usage_with_options(bench_usage, options);
71 exit(EXIT_FAILURE);
72 }
73
74 return do_kallsyms_parse();
75 }
76