xref: /openbmc/linux/tools/perf/tests/sw-clock.c (revision 20ff1cb5)
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/thread_map.h"
16 #include <perf/evlist.h>
17 
18 #define NR_LOOPS  10000000
19 
20 /*
21  * This test will open software clock events (cpu-clock, task-clock)
22  * then check their frequency -> period conversion has no artifact of
23  * setting period to 1 forcefully.
24  */
25 static int __test__sw_clock_freq(enum perf_sw_ids clock_id)
26 {
27 	int i, err = -1;
28 	volatile int tmp = 0;
29 	u64 total_periods = 0;
30 	int nr_samples = 0;
31 	char sbuf[STRERR_BUFSIZE];
32 	union perf_event *event;
33 	struct evsel *evsel;
34 	struct evlist *evlist;
35 	struct perf_event_attr attr = {
36 		.type = PERF_TYPE_SOFTWARE,
37 		.config = clock_id,
38 		.sample_type = PERF_SAMPLE_PERIOD,
39 		.exclude_kernel = 1,
40 		.disabled = 1,
41 		.freq = 1,
42 	};
43 	struct perf_cpu_map *cpus;
44 	struct perf_thread_map *threads;
45 	struct perf_mmap *md;
46 
47 	attr.sample_freq = 500;
48 
49 	evlist = evlist__new();
50 	if (evlist == NULL) {
51 		pr_debug("evlist__new\n");
52 		return -1;
53 	}
54 
55 	evsel = evsel__new(&attr);
56 	if (evsel == NULL) {
57 		pr_debug("perf_evsel__new\n");
58 		goto out_delete_evlist;
59 	}
60 	evlist__add(evlist, evsel);
61 
62 	cpus = perf_cpu_map__dummy_new();
63 	threads = thread_map__new_by_tid(getpid());
64 	if (!cpus || !threads) {
65 		err = -ENOMEM;
66 		pr_debug("Not enough memory to create thread/cpu maps\n");
67 		goto out_free_maps;
68 	}
69 
70 	perf_evlist__set_maps(&evlist->core, cpus, threads);
71 
72 	cpus	= NULL;
73 	threads = NULL;
74 
75 	if (evlist__open(evlist)) {
76 		const char *knob = "/proc/sys/kernel/perf_event_max_sample_rate";
77 
78 		err = -errno;
79 		pr_debug("Couldn't open evlist: %s\nHint: check %s, using %" PRIu64 " in this test.\n",
80 			 str_error_r(errno, sbuf, sizeof(sbuf)),
81 			 knob, (u64)attr.sample_freq);
82 		goto out_delete_evlist;
83 	}
84 
85 	err = perf_evlist__mmap(evlist, 128);
86 	if (err < 0) {
87 		pr_debug("failed to mmap event: %d (%s)\n", errno,
88 			 str_error_r(errno, sbuf, sizeof(sbuf)));
89 		goto out_delete_evlist;
90 	}
91 
92 	evlist__enable(evlist);
93 
94 	/* collect samples */
95 	for (i = 0; i < NR_LOOPS; i++)
96 		tmp++;
97 
98 	evlist__disable(evlist);
99 
100 	md = &evlist->mmap[0];
101 	if (perf_mmap__read_init(md) < 0)
102 		goto out_init;
103 
104 	while ((event = perf_mmap__read_event(md)) != NULL) {
105 		struct perf_sample sample;
106 
107 		if (event->header.type != PERF_RECORD_SAMPLE)
108 			goto next_event;
109 
110 		err = perf_evlist__parse_sample(evlist, event, &sample);
111 		if (err < 0) {
112 			pr_debug("Error during parse sample\n");
113 			goto out_delete_evlist;
114 		}
115 
116 		total_periods += sample.period;
117 		nr_samples++;
118 next_event:
119 		perf_mmap__consume(md);
120 	}
121 	perf_mmap__read_done(md);
122 
123 out_init:
124 	if ((u64) nr_samples == total_periods) {
125 		pr_debug("All (%d) samples have period value of 1!\n",
126 			 nr_samples);
127 		err = -1;
128 	}
129 
130 out_free_maps:
131 	perf_cpu_map__put(cpus);
132 	perf_thread_map__put(threads);
133 out_delete_evlist:
134 	evlist__delete(evlist);
135 	return err;
136 }
137 
138 int test__sw_clock_freq(struct test *test __maybe_unused, int subtest __maybe_unused)
139 {
140 	int ret;
141 
142 	ret = __test__sw_clock_freq(PERF_COUNT_SW_CPU_CLOCK);
143 	if (!ret)
144 		ret = __test__sw_clock_freq(PERF_COUNT_SW_TASK_CLOCK);
145 
146 	return ret;
147 }
148