xref: /linux/tools/perf/tests/sw-clock.c (revision bbcd53c960713507ae764bf81970651b5577b95a)
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 #include <linux/string.h>
9 
10 #include "tests.h"
11 #include "util/debug.h"
12 #include "util/evsel.h"
13 #include "util/evlist.h"
14 #include "util/cpumap.h"
15 #include "util/mmap.h"
16 #include "util/thread_map.h"
17 #include <perf/evlist.h>
18 #include <perf/mmap.h>
19 
20 #define NR_LOOPS  10000000
21 
22 /*
23  * This test will open software clock events (cpu-clock, task-clock)
24  * then check their frequency -> period conversion has no artifact of
25  * setting period to 1 forcefully.
26  */
27 static int __test__sw_clock_freq(enum perf_sw_ids clock_id)
28 {
29 	int i, err = -1;
30 	volatile int tmp = 0;
31 	u64 total_periods = 0;
32 	int nr_samples = 0;
33 	char sbuf[STRERR_BUFSIZE];
34 	union perf_event *event;
35 	struct evsel *evsel;
36 	struct evlist *evlist;
37 	struct perf_event_attr attr = {
38 		.type = PERF_TYPE_SOFTWARE,
39 		.config = clock_id,
40 		.sample_type = PERF_SAMPLE_PERIOD,
41 		.exclude_kernel = 1,
42 		.disabled = 1,
43 		.freq = 1,
44 	};
45 	struct perf_cpu_map *cpus = NULL;
46 	struct perf_thread_map *threads = NULL;
47 	struct mmap *md;
48 
49 	attr.sample_freq = 500;
50 
51 	evlist = evlist__new();
52 	if (evlist == NULL) {
53 		pr_debug("evlist__new\n");
54 		return -1;
55 	}
56 
57 	evsel = evsel__new(&attr);
58 	if (evsel == NULL) {
59 		pr_debug("evsel__new\n");
60 		goto out_delete_evlist;
61 	}
62 	evlist__add(evlist, evsel);
63 
64 	cpus = perf_cpu_map__dummy_new();
65 	threads = thread_map__new_by_tid(getpid());
66 	if (!cpus || !threads) {
67 		err = -ENOMEM;
68 		pr_debug("Not enough memory to create thread/cpu maps\n");
69 		goto out_delete_evlist;
70 	}
71 
72 	perf_evlist__set_maps(&evlist->core, cpus, threads);
73 
74 	if (evlist__open(evlist)) {
75 		const char *knob = "/proc/sys/kernel/perf_event_max_sample_rate";
76 
77 		err = -errno;
78 		pr_debug("Couldn't open evlist: %s\nHint: check %s, using %" PRIu64 " in this test.\n",
79 			 str_error_r(errno, sbuf, sizeof(sbuf)),
80 			 knob, (u64)attr.sample_freq);
81 		goto out_delete_evlist;
82 	}
83 
84 	err = evlist__mmap(evlist, 128);
85 	if (err < 0) {
86 		pr_debug("failed to mmap event: %d (%s)\n", errno,
87 			 str_error_r(errno, sbuf, sizeof(sbuf)));
88 		goto out_delete_evlist;
89 	}
90 
91 	evlist__enable(evlist);
92 
93 	/* collect samples */
94 	for (i = 0; i < NR_LOOPS; i++)
95 		tmp++;
96 
97 	evlist__disable(evlist);
98 
99 	md = &evlist->mmap[0];
100 	if (perf_mmap__read_init(&md->core) < 0)
101 		goto out_init;
102 
103 	while ((event = perf_mmap__read_event(&md->core)) != NULL) {
104 		struct perf_sample sample;
105 
106 		if (event->header.type != PERF_RECORD_SAMPLE)
107 			goto next_event;
108 
109 		err = evlist__parse_sample(evlist, event, &sample);
110 		if (err < 0) {
111 			pr_debug("Error during parse sample\n");
112 			goto out_delete_evlist;
113 		}
114 
115 		total_periods += sample.period;
116 		nr_samples++;
117 next_event:
118 		perf_mmap__consume(&md->core);
119 	}
120 	perf_mmap__read_done(&md->core);
121 
122 out_init:
123 	if ((u64) nr_samples == total_periods) {
124 		pr_debug("All (%d) samples have period value of 1!\n",
125 			 nr_samples);
126 		err = -1;
127 	}
128 
129 out_delete_evlist:
130 	perf_cpu_map__put(cpus);
131 	perf_thread_map__put(threads);
132 	evlist__delete(evlist);
133 	return err;
134 }
135 
136 int test__sw_clock_freq(struct test *test __maybe_unused, int subtest __maybe_unused)
137 {
138 	int ret;
139 
140 	ret = __test__sw_clock_freq(PERF_COUNT_SW_CPU_CLOCK);
141 	if (!ret)
142 		ret = __test__sw_clock_freq(PERF_COUNT_SW_TASK_CLOCK);
143 
144 	return ret;
145 }
146