xref: /openbmc/linux/tools/perf/tests/sw-clock.c (revision be709d48)
1 // SPDX-License-Identifier: GPL-2.0
2 #include <errno.h>
3 #include <inttypes.h>
4 #include <unistd.h>
5 #include <stdlib.h>
6 #include <signal.h>
7 #include <sys/mman.h>
8 
9 #include "tests.h"
10 #include "util/evsel.h"
11 #include "util/evlist.h"
12 #include "util/cpumap.h"
13 #include "util/thread_map.h"
14 
15 #define NR_LOOPS  10000000
16 
17 /*
18  * This test will open software clock events (cpu-clock, task-clock)
19  * then check their frequency -> period conversion has no artifact of
20  * setting period to 1 forcefully.
21  */
22 static int __test__sw_clock_freq(enum perf_sw_ids clock_id)
23 {
24 	int i, err = -1;
25 	volatile int tmp = 0;
26 	u64 total_periods = 0;
27 	int nr_samples = 0;
28 	char sbuf[STRERR_BUFSIZE];
29 	union perf_event *event;
30 	struct perf_evsel *evsel;
31 	struct perf_evlist *evlist;
32 	struct perf_event_attr attr = {
33 		.type = PERF_TYPE_SOFTWARE,
34 		.config = clock_id,
35 		.sample_type = PERF_SAMPLE_PERIOD,
36 		.exclude_kernel = 1,
37 		.disabled = 1,
38 		.freq = 1,
39 	};
40 	struct cpu_map *cpus;
41 	struct thread_map *threads;
42 	struct perf_mmap *md;
43 
44 	attr.sample_freq = 500;
45 
46 	evlist = perf_evlist__new();
47 	if (evlist == NULL) {
48 		pr_debug("perf_evlist__new\n");
49 		return -1;
50 	}
51 
52 	evsel = perf_evsel__new(&attr);
53 	if (evsel == NULL) {
54 		pr_debug("perf_evsel__new\n");
55 		goto out_delete_evlist;
56 	}
57 	perf_evlist__add(evlist, evsel);
58 
59 	cpus = cpu_map__dummy_new();
60 	threads = thread_map__new_by_tid(getpid());
61 	if (!cpus || !threads) {
62 		err = -ENOMEM;
63 		pr_debug("Not enough memory to create thread/cpu maps\n");
64 		goto out_free_maps;
65 	}
66 
67 	perf_evlist__set_maps(evlist, cpus, threads);
68 
69 	cpus	= NULL;
70 	threads = NULL;
71 
72 	if (perf_evlist__open(evlist)) {
73 		const char *knob = "/proc/sys/kernel/perf_event_max_sample_rate";
74 
75 		err = -errno;
76 		pr_debug("Couldn't open evlist: %s\nHint: check %s, using %" PRIu64 " in this test.\n",
77 			 str_error_r(errno, sbuf, sizeof(sbuf)),
78 			 knob, (u64)attr.sample_freq);
79 		goto out_delete_evlist;
80 	}
81 
82 	err = perf_evlist__mmap(evlist, 128);
83 	if (err < 0) {
84 		pr_debug("failed to mmap event: %d (%s)\n", errno,
85 			 str_error_r(errno, sbuf, sizeof(sbuf)));
86 		goto out_delete_evlist;
87 	}
88 
89 	perf_evlist__enable(evlist);
90 
91 	/* collect samples */
92 	for (i = 0; i < NR_LOOPS; i++)
93 		tmp++;
94 
95 	perf_evlist__disable(evlist);
96 
97 	md = &evlist->mmap[0];
98 	if (perf_mmap__read_init(md) < 0)
99 		goto out_init;
100 
101 	while ((event = perf_mmap__read_event(md)) != NULL) {
102 		struct perf_sample sample;
103 
104 		if (event->header.type != PERF_RECORD_SAMPLE)
105 			goto next_event;
106 
107 		err = perf_evlist__parse_sample(evlist, event, &sample);
108 		if (err < 0) {
109 			pr_debug("Error during parse sample\n");
110 			goto out_delete_evlist;
111 		}
112 
113 		total_periods += sample.period;
114 		nr_samples++;
115 next_event:
116 		perf_mmap__consume(md);
117 	}
118 	perf_mmap__read_done(md);
119 
120 out_init:
121 	if ((u64) nr_samples == total_periods) {
122 		pr_debug("All (%d) samples have period value of 1!\n",
123 			 nr_samples);
124 		err = -1;
125 	}
126 
127 out_free_maps:
128 	cpu_map__put(cpus);
129 	thread_map__put(threads);
130 out_delete_evlist:
131 	perf_evlist__delete(evlist);
132 	return err;
133 }
134 
135 int test__sw_clock_freq(struct test *test __maybe_unused, int subtest __maybe_unused)
136 {
137 	int ret;
138 
139 	ret = __test__sw_clock_freq(PERF_COUNT_SW_CPU_CLOCK);
140 	if (!ret)
141 		ret = __test__sw_clock_freq(PERF_COUNT_SW_TASK_CLOCK);
142 
143 	return ret;
144 }
145