perf/tests/sw-clock.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 #include <errno.h>
0003 #include <inttypes.h>
0004 #include <unistd.h>
0005 #include <stdlib.h>
0006 #include <signal.h>
0007 #include <sys/mman.h>
0008 #include <linux/string.h>
0009
0010 #include "tests.h"
0011 #include "util/debug.h"
0012 #include "util/evsel.h"
0013 #include "util/evlist.h"
0014 #include "util/cpumap.h"
0015 #include "util/mmap.h"
0016 #include "util/thread_map.h"
0017 #include <perf/evlist.h>
0018 #include <perf/mmap.h>
0019
0020 #define NR_LOOPS  10000000
0021
0022 /*
0023  * This test will open software clock events (cpu-clock, task-clock)
0024  * then check their frequency -> period conversion has no artifact of
0025  * setting period to 1 forcefully.
0026  */
0027 static int __test__sw_clock_freq(enum perf_sw_ids clock_id)
0028 {
0029     int i, err = -1;
0030     volatile int tmp = 0;
0031     u64 total_periods = 0;
0032     int nr_samples = 0;
0033     char sbuf[STRERR_BUFSIZE];
0034     union perf_event *event;
0035     struct evsel *evsel;
0036     struct evlist *evlist;
0037     struct perf_event_attr attr = {
0038         .type = PERF_TYPE_SOFTWARE,
0039         .config = clock_id,
0040         .sample_type = PERF_SAMPLE_PERIOD,
0041         .exclude_kernel = 1,
0042         .disabled = 1,
0043         .freq = 1,
0044     };
0045     struct perf_cpu_map *cpus = NULL;
0046     struct perf_thread_map *threads = NULL;
0047     struct mmap *md;
0048
0049     attr.sample_freq = 500;
0050
0051     evlist = evlist__new();
0052     if (evlist == NULL) {
0053         pr_debug("evlist__new\n");
0054         return -1;
0055     }
0056
0057     evsel = evsel__new(&attr);
0058     if (evsel == NULL) {
0059         pr_debug("evsel__new\n");
0060         goto out_delete_evlist;
0061     }
0062     evlist__add(evlist, evsel);
0063
0064     cpus = perf_cpu_map__dummy_new();
0065     threads = thread_map__new_by_tid(getpid());
0066     if (!cpus || !threads) {
0067         err = -ENOMEM;
0068         pr_debug("Not enough memory to create thread/cpu maps\n");
0069         goto out_delete_evlist;
0070     }
0071
0072     perf_evlist__set_maps(&evlist->core, cpus, threads);
0073
0074     if (evlist__open(evlist)) {
0075         const char *knob = "/proc/sys/kernel/perf_event_max_sample_rate";
0076
0077         err = -errno;
0078         pr_debug("Couldn't open evlist: %s\nHint: check %s, using %" PRIu64 " in this test.\n",
0079              str_error_r(errno, sbuf, sizeof(sbuf)),
0080              knob, (u64)attr.sample_freq);
0081         goto out_delete_evlist;
0082     }
0083
0084     err = evlist__mmap(evlist, 128);
0085     if (err < 0) {
0086         pr_debug("failed to mmap event: %d (%s)\n", errno,
0087              str_error_r(errno, sbuf, sizeof(sbuf)));
0088         goto out_delete_evlist;
0089     }
0090
0091     evlist__enable(evlist);
0092
0093     /* collect samples */
0094     for (i = 0; i < NR_LOOPS; i++)
0095         tmp++;
0096
0097     evlist__disable(evlist);
0098
0099     md = &evlist->mmap[0];
0100     if (perf_mmap__read_init(&md->core) < 0)
0101         goto out_init;
0102
0103     while ((event = perf_mmap__read_event(&md->core)) != NULL) {
0104         struct perf_sample sample;
0105
0106         if (event->header.type != PERF_RECORD_SAMPLE)
0107             goto next_event;
0108
0109         err = evlist__parse_sample(evlist, event, &sample);
0110         if (err < 0) {
0111             pr_debug("Error during parse sample\n");
0112             goto out_delete_evlist;
0113         }
0114
0115         total_periods += sample.period;
0116         nr_samples++;
0117 next_event:
0118         perf_mmap__consume(&md->core);
0119     }
0120     perf_mmap__read_done(&md->core);
0121
0122 out_init:
0123     if ((u64) nr_samples == total_periods) {
0124         pr_debug("All (%d) samples have period value of 1!\n",
0125              nr_samples);
0126         err = -1;
0127     }
0128
0129 out_delete_evlist:
0130     perf_cpu_map__put(cpus);
0131     perf_thread_map__put(threads);
0132     evlist__delete(evlist);
0133     return err;
0134 }
0135
0136 static int test__sw_clock_freq(struct test_suite *test __maybe_unused, int subtest __maybe_unused)
0137 {
0138     int ret;
0139
0140     ret = __test__sw_clock_freq(PERF_COUNT_SW_CPU_CLOCK);
0141     if (!ret)
0142         ret = __test__sw_clock_freq(PERF_COUNT_SW_TASK_CLOCK);
0143
0144     return ret;
0145 }
0146
0147 DEFINE_SUITE("Software clock events period values", sw_clock_freq);