xref: /linux/tools/perf/tests/sw-clock.c (revision b85d45947951d23cb22d90caecf4c1eb81342c96)
1 #include <unistd.h>
2 #include <stdlib.h>
3 #include <signal.h>
4 #include <sys/mman.h>
5 
6 #include "tests.h"
7 #include "util/evsel.h"
8 #include "util/evlist.h"
9 #include "util/cpumap.h"
10 #include "util/thread_map.h"
11 
12 #define NR_LOOPS  10000000
13 
14 /*
15  * This test will open software clock events (cpu-clock, task-clock)
16  * then check their frequency -> period conversion has no artifact of
17  * setting period to 1 forcefully.
18  */
19 static int __test__sw_clock_freq(enum perf_sw_ids clock_id)
20 {
21 	int i, err = -1;
22 	volatile int tmp = 0;
23 	u64 total_periods = 0;
24 	int nr_samples = 0;
25 	char sbuf[STRERR_BUFSIZE];
26 	union perf_event *event;
27 	struct perf_evsel *evsel;
28 	struct perf_evlist *evlist;
29 	struct perf_event_attr attr = {
30 		.type = PERF_TYPE_SOFTWARE,
31 		.config = clock_id,
32 		.sample_type = PERF_SAMPLE_PERIOD,
33 		.exclude_kernel = 1,
34 		.disabled = 1,
35 		.freq = 1,
36 	};
37 	struct cpu_map *cpus;
38 	struct thread_map *threads;
39 
40 	attr.sample_freq = 500;
41 
42 	evlist = perf_evlist__new();
43 	if (evlist == NULL) {
44 		pr_debug("perf_evlist__new\n");
45 		return -1;
46 	}
47 
48 	evsel = perf_evsel__new(&attr);
49 	if (evsel == NULL) {
50 		pr_debug("perf_evsel__new\n");
51 		goto out_delete_evlist;
52 	}
53 	perf_evlist__add(evlist, evsel);
54 
55 	cpus = cpu_map__dummy_new();
56 	threads = thread_map__new_by_tid(getpid());
57 	if (!cpus || !threads) {
58 		err = -ENOMEM;
59 		pr_debug("Not enough memory to create thread/cpu maps\n");
60 		goto out_free_maps;
61 	}
62 
63 	perf_evlist__set_maps(evlist, cpus, threads);
64 
65 	cpus	= NULL;
66 	threads = NULL;
67 
68 	if (perf_evlist__open(evlist)) {
69 		const char *knob = "/proc/sys/kernel/perf_event_max_sample_rate";
70 
71 		err = -errno;
72 		pr_debug("Couldn't open evlist: %s\nHint: check %s, using %" PRIu64 " in this test.\n",
73 			 strerror_r(errno, sbuf, sizeof(sbuf)),
74 			 knob, (u64)attr.sample_freq);
75 		goto out_delete_evlist;
76 	}
77 
78 	err = perf_evlist__mmap(evlist, 128, true);
79 	if (err < 0) {
80 		pr_debug("failed to mmap event: %d (%s)\n", errno,
81 			 strerror_r(errno, sbuf, sizeof(sbuf)));
82 		goto out_delete_evlist;
83 	}
84 
85 	perf_evlist__enable(evlist);
86 
87 	/* collect samples */
88 	for (i = 0; i < NR_LOOPS; i++)
89 		tmp++;
90 
91 	perf_evlist__disable(evlist);
92 
93 	while ((event = perf_evlist__mmap_read(evlist, 0)) != NULL) {
94 		struct perf_sample sample;
95 
96 		if (event->header.type != PERF_RECORD_SAMPLE)
97 			goto next_event;
98 
99 		err = perf_evlist__parse_sample(evlist, event, &sample);
100 		if (err < 0) {
101 			pr_debug("Error during parse sample\n");
102 			goto out_delete_evlist;
103 		}
104 
105 		total_periods += sample.period;
106 		nr_samples++;
107 next_event:
108 		perf_evlist__mmap_consume(evlist, 0);
109 	}
110 
111 	if ((u64) nr_samples == total_periods) {
112 		pr_debug("All (%d) samples have period value of 1!\n",
113 			 nr_samples);
114 		err = -1;
115 	}
116 
117 out_free_maps:
118 	cpu_map__put(cpus);
119 	thread_map__put(threads);
120 out_delete_evlist:
121 	perf_evlist__delete(evlist);
122 	return err;
123 }
124 
125 int test__sw_clock_freq(void)
126 {
127 	int ret;
128 
129 	ret = __test__sw_clock_freq(PERF_COUNT_SW_CPU_CLOCK);
130 	if (!ret)
131 		ret = __test__sw_clock_freq(PERF_COUNT_SW_TASK_CLOCK);
132 
133 	return ret;
134 }
135