xref: /openbmc/linux/tools/perf/tests/sw-clock.c (revision 8795a739)
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 
19 #define NR_LOOPS  10000000
20 
21 /*
22  * This test will open software clock events (cpu-clock, task-clock)
23  * then check their frequency -> period conversion has no artifact of
24  * setting period to 1 forcefully.
25  */
26 static int __test__sw_clock_freq(enum perf_sw_ids clock_id)
27 {
28 	int i, err = -1;
29 	volatile int tmp = 0;
30 	u64 total_periods = 0;
31 	int nr_samples = 0;
32 	char sbuf[STRERR_BUFSIZE];
33 	union perf_event *event;
34 	struct evsel *evsel;
35 	struct evlist *evlist;
36 	struct perf_event_attr attr = {
37 		.type = PERF_TYPE_SOFTWARE,
38 		.config = clock_id,
39 		.sample_type = PERF_SAMPLE_PERIOD,
40 		.exclude_kernel = 1,
41 		.disabled = 1,
42 		.freq = 1,
43 	};
44 	struct perf_cpu_map *cpus;
45 	struct perf_thread_map *threads;
46 	struct mmap *md;
47 
48 	attr.sample_freq = 500;
49 
50 	evlist = evlist__new();
51 	if (evlist == NULL) {
52 		pr_debug("evlist__new\n");
53 		return -1;
54 	}
55 
56 	evsel = evsel__new(&attr);
57 	if (evsel == NULL) {
58 		pr_debug("perf_evsel__new\n");
59 		goto out_delete_evlist;
60 	}
61 	evlist__add(evlist, evsel);
62 
63 	cpus = perf_cpu_map__dummy_new();
64 	threads = thread_map__new_by_tid(getpid());
65 	if (!cpus || !threads) {
66 		err = -ENOMEM;
67 		pr_debug("Not enough memory to create thread/cpu maps\n");
68 		goto out_free_maps;
69 	}
70 
71 	perf_evlist__set_maps(&evlist->core, cpus, threads);
72 
73 	cpus	= NULL;
74 	threads = NULL;
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) < 0)
103 		goto out_init;
104 
105 	while ((event = perf_mmap__read_event(md)) != NULL) {
106 		struct perf_sample sample;
107 
108 		if (event->header.type != PERF_RECORD_SAMPLE)
109 			goto next_event;
110 
111 		err = perf_evlist__parse_sample(evlist, event, &sample);
112 		if (err < 0) {
113 			pr_debug("Error during parse sample\n");
114 			goto out_delete_evlist;
115 		}
116 
117 		total_periods += sample.period;
118 		nr_samples++;
119 next_event:
120 		perf_mmap__consume(md);
121 	}
122 	perf_mmap__read_done(md);
123 
124 out_init:
125 	if ((u64) nr_samples == total_periods) {
126 		pr_debug("All (%d) samples have period value of 1!\n",
127 			 nr_samples);
128 		err = -1;
129 	}
130 
131 out_free_maps:
132 	perf_cpu_map__put(cpus);
133 	perf_thread_map__put(threads);
134 out_delete_evlist:
135 	evlist__delete(evlist);
136 	return err;
137 }
138 
139 int test__sw_clock_freq(struct test *test __maybe_unused, int subtest __maybe_unused)
140 {
141 	int ret;
142 
143 	ret = __test__sw_clock_freq(PERF_COUNT_SW_CPU_CLOCK);
144 	if (!ret)
145 		ret = __test__sw_clock_freq(PERF_COUNT_SW_TASK_CLOCK);
146 
147 	return ret;
148 }
149