xref: /linux/tools/perf/tests/sw-clock.c (revision 42fc2e9ef9603a7948aaa4ffd8dfb94b30294ad8)
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 #include <perf/evlist.h>
15 
16 #define NR_LOOPS  10000000
17 
18 /*
19  * This test will open software clock events (cpu-clock, task-clock)
20  * then check their frequency -> period conversion has no artifact of
21  * setting period to 1 forcefully.
22  */
23 static int __test__sw_clock_freq(enum perf_sw_ids clock_id)
24 {
25 	int i, err = -1;
26 	volatile int tmp = 0;
27 	u64 total_periods = 0;
28 	int nr_samples = 0;
29 	char sbuf[STRERR_BUFSIZE];
30 	union perf_event *event;
31 	struct evsel *evsel;
32 	struct evlist *evlist;
33 	struct perf_event_attr attr = {
34 		.type = PERF_TYPE_SOFTWARE,
35 		.config = clock_id,
36 		.sample_type = PERF_SAMPLE_PERIOD,
37 		.exclude_kernel = 1,
38 		.disabled = 1,
39 		.freq = 1,
40 	};
41 	struct perf_cpu_map *cpus;
42 	struct perf_thread_map *threads;
43 	struct perf_mmap *md;
44 
45 	attr.sample_freq = 500;
46 
47 	evlist = evlist__new();
48 	if (evlist == NULL) {
49 		pr_debug("evlist__new\n");
50 		return -1;
51 	}
52 
53 	evsel = evsel__new(&attr);
54 	if (evsel == NULL) {
55 		pr_debug("perf_evsel__new\n");
56 		goto out_delete_evlist;
57 	}
58 	evlist__add(evlist, evsel);
59 
60 	cpus = perf_cpu_map__dummy_new();
61 	threads = thread_map__new_by_tid(getpid());
62 	if (!cpus || !threads) {
63 		err = -ENOMEM;
64 		pr_debug("Not enough memory to create thread/cpu maps\n");
65 		goto out_free_maps;
66 	}
67 
68 	perf_evlist__set_maps(&evlist->core, cpus, threads);
69 
70 	cpus	= NULL;
71 	threads = NULL;
72 
73 	if (evlist__open(evlist)) {
74 		const char *knob = "/proc/sys/kernel/perf_event_max_sample_rate";
75 
76 		err = -errno;
77 		pr_debug("Couldn't open evlist: %s\nHint: check %s, using %" PRIu64 " in this test.\n",
78 			 str_error_r(errno, sbuf, sizeof(sbuf)),
79 			 knob, (u64)attr.sample_freq);
80 		goto out_delete_evlist;
81 	}
82 
83 	err = perf_evlist__mmap(evlist, 128);
84 	if (err < 0) {
85 		pr_debug("failed to mmap event: %d (%s)\n", errno,
86 			 str_error_r(errno, sbuf, sizeof(sbuf)));
87 		goto out_delete_evlist;
88 	}
89 
90 	evlist__enable(evlist);
91 
92 	/* collect samples */
93 	for (i = 0; i < NR_LOOPS; i++)
94 		tmp++;
95 
96 	evlist__disable(evlist);
97 
98 	md = &evlist->mmap[0];
99 	if (perf_mmap__read_init(md) < 0)
100 		goto out_init;
101 
102 	while ((event = perf_mmap__read_event(md)) != NULL) {
103 		struct perf_sample sample;
104 
105 		if (event->header.type != PERF_RECORD_SAMPLE)
106 			goto next_event;
107 
108 		err = perf_evlist__parse_sample(evlist, event, &sample);
109 		if (err < 0) {
110 			pr_debug("Error during parse sample\n");
111 			goto out_delete_evlist;
112 		}
113 
114 		total_periods += sample.period;
115 		nr_samples++;
116 next_event:
117 		perf_mmap__consume(md);
118 	}
119 	perf_mmap__read_done(md);
120 
121 out_init:
122 	if ((u64) nr_samples == total_periods) {
123 		pr_debug("All (%d) samples have period value of 1!\n",
124 			 nr_samples);
125 		err = -1;
126 	}
127 
128 out_free_maps:
129 	perf_cpu_map__put(cpus);
130 	perf_thread_map__put(threads);
131 out_delete_evlist:
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