xref: /linux/tools/perf/tests/sw-clock.c (revision d198b34f3855eee2571dda03eea75a09c7c31480)
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;
46 	struct perf_thread_map *threads;
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("perf_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_free_maps;
70 	}
71 
72 	perf_evlist__set_maps(&evlist->core, cpus, threads);
73 
74 	cpus	= NULL;
75 	threads = NULL;
76 
77 	if (evlist__open(evlist)) {
78 		const char *knob = "/proc/sys/kernel/perf_event_max_sample_rate";
79 
80 		err = -errno;
81 		pr_debug("Couldn't open evlist: %s\nHint: check %s, using %" PRIu64 " in this test.\n",
82 			 str_error_r(errno, sbuf, sizeof(sbuf)),
83 			 knob, (u64)attr.sample_freq);
84 		goto out_delete_evlist;
85 	}
86 
87 	err = evlist__mmap(evlist, 128);
88 	if (err < 0) {
89 		pr_debug("failed to mmap event: %d (%s)\n", errno,
90 			 str_error_r(errno, sbuf, sizeof(sbuf)));
91 		goto out_delete_evlist;
92 	}
93 
94 	evlist__enable(evlist);
95 
96 	/* collect samples */
97 	for (i = 0; i < NR_LOOPS; i++)
98 		tmp++;
99 
100 	evlist__disable(evlist);
101 
102 	md = &evlist->mmap[0];
103 	if (perf_mmap__read_init(&md->core) < 0)
104 		goto out_init;
105 
106 	while ((event = perf_mmap__read_event(&md->core)) != NULL) {
107 		struct perf_sample sample;
108 
109 		if (event->header.type != PERF_RECORD_SAMPLE)
110 			goto next_event;
111 
112 		err = perf_evlist__parse_sample(evlist, event, &sample);
113 		if (err < 0) {
114 			pr_debug("Error during parse sample\n");
115 			goto out_delete_evlist;
116 		}
117 
118 		total_periods += sample.period;
119 		nr_samples++;
120 next_event:
121 		perf_mmap__consume(&md->core);
122 	}
123 	perf_mmap__read_done(&md->core);
124 
125 out_init:
126 	if ((u64) nr_samples == total_periods) {
127 		pr_debug("All (%d) samples have period value of 1!\n",
128 			 nr_samples);
129 		err = -1;
130 	}
131 
132 out_free_maps:
133 	perf_cpu_map__put(cpus);
134 	perf_thread_map__put(threads);
135 out_delete_evlist:
136 	evlist__delete(evlist);
137 	return err;
138 }
139 
140 int test__sw_clock_freq(struct test *test __maybe_unused, int subtest __maybe_unused)
141 {
142 	int ret;
143 
144 	ret = __test__sw_clock_freq(PERF_COUNT_SW_CPU_CLOCK);
145 	if (!ret)
146 		ret = __test__sw_clock_freq(PERF_COUNT_SW_TASK_CLOCK);
147 
148 	return ret;
149 }
150