xref: /linux/tools/perf/tests/sw-clock.c (revision bf4afc53b77aeaa48b5409da5c8da6bb4eff7f43)
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/compiler.h>
9 #include <linux/string.h>
10 
11 #include "tests.h"
12 #include "util/debug.h"
13 #include "util/evsel.h"
14 #include "util/evlist.h"
15 #include "util/cpumap.h"
16 #include "util/mmap.h"
17 #include "util/sample.h"
18 #include "util/thread_map.h"
19 #include <perf/evlist.h>
20 #include <perf/mmap.h>
21 
22 #define NR_LOOPS  10000000
23 
24 /*
25  * This test will open software clock events (cpu-clock, task-clock)
26  * then check their frequency -> period conversion has no artifact of
27  * setting period to 1 forcefully.
28  */
29 static int __test__sw_clock_freq(enum perf_sw_ids clock_id)
30 {
31 	int i, err = -1;
32 	volatile int tmp __maybe_unused = 0;
33 	u64 total_periods = 0;
34 	int nr_samples = 0;
35 	char sbuf[STRERR_BUFSIZE];
36 	union perf_event *event;
37 	struct evsel *evsel;
38 	struct evlist *evlist;
39 	struct perf_event_attr attr = {
40 		.type = PERF_TYPE_SOFTWARE,
41 		.config = clock_id,
42 		.sample_type = PERF_SAMPLE_PERIOD,
43 		.exclude_kernel = 1,
44 		.disabled = 1,
45 		.freq = 1,
46 	};
47 	struct perf_cpu_map *cpus = NULL;
48 	struct perf_thread_map *threads = NULL;
49 	struct mmap *md;
50 
51 	attr.sample_freq = 500;
52 
53 	evlist = evlist__new();
54 	if (evlist == NULL) {
55 		pr_debug("evlist__new\n");
56 		return -1;
57 	}
58 
59 	evsel = evsel__new(&attr);
60 	if (evsel == NULL) {
61 		pr_debug("evsel__new\n");
62 		goto out_delete_evlist;
63 	}
64 	evlist__add(evlist, evsel);
65 
66 	cpus = perf_cpu_map__new_any_cpu();
67 	threads = thread_map__new_by_tid(getpid());
68 	if (!cpus || !threads) {
69 		err = -ENOMEM;
70 		pr_debug("Not enough memory to create thread/cpu maps\n");
71 		goto out_delete_evlist;
72 	}
73 
74 	perf_evlist__set_maps(&evlist->core, cpus, threads);
75 
76 	if (evlist__open(evlist)) {
77 		const char *knob = "/proc/sys/kernel/perf_event_max_sample_rate";
78 
79 		err = -errno;
80 		pr_debug("Couldn't open evlist: %s\nHint: check %s, using %" PRIu64 " in this test.\n",
81 			 str_error_r(errno, sbuf, sizeof(sbuf)),
82 			 knob, (u64)attr.sample_freq);
83 		goto out_delete_evlist;
84 	}
85 
86 	err = evlist__mmap(evlist, 128);
87 	if (err < 0) {
88 		pr_debug("failed to mmap event: %d (%s)\n", errno,
89 			 str_error_r(errno, sbuf, sizeof(sbuf)));
90 		goto out_delete_evlist;
91 	}
92 
93 	evlist__enable(evlist);
94 
95 	/* collect samples */
96 	for (i = 0; i < NR_LOOPS; i++)
97 		tmp++;
98 
99 	evlist__disable(evlist);
100 
101 	md = &evlist->mmap[0];
102 	if (perf_mmap__read_init(&md->core) < 0)
103 		goto out_init;
104 
105 	while ((event = perf_mmap__read_event(&md->core)) != NULL) {
106 		struct perf_sample sample;
107 
108 		perf_sample__init(&sample, /*all=*/false);
109 		if (event->header.type != PERF_RECORD_SAMPLE)
110 			goto next_event;
111 
112 		err = evlist__parse_sample(evlist, event, &sample);
113 		if (err < 0) {
114 			pr_debug("Error during parse sample\n");
115 			perf_sample__exit(&sample);
116 			goto out_delete_evlist;
117 		}
118 
119 		total_periods += sample.period;
120 		nr_samples++;
121 next_event:
122 		perf_mmap__consume(&md->core);
123 		perf_sample__exit(&sample);
124 	}
125 	perf_mmap__read_done(&md->core);
126 
127 out_init:
128 	if ((u64) nr_samples == total_periods) {
129 		pr_debug("All (%d) samples have period value of 1!\n",
130 			 nr_samples);
131 		err = -1;
132 	}
133 
134 out_delete_evlist:
135 	perf_cpu_map__put(cpus);
136 	perf_thread_map__put(threads);
137 	evlist__delete(evlist);
138 	return err;
139 }
140 
141 static int test__sw_clock_freq(struct test_suite *test __maybe_unused, int subtest __maybe_unused)
142 {
143 	int ret;
144 
145 	ret = __test__sw_clock_freq(PERF_COUNT_SW_CPU_CLOCK);
146 	if (!ret)
147 		ret = __test__sw_clock_freq(PERF_COUNT_SW_TASK_CLOCK);
148 
149 	return ret;
150 }
151 
152 DEFINE_SUITE("Software clock events period values", sw_clock_freq);
153