xref: /openbmc/linux/tools/perf/tests/sw-clock.c (revision 92b19ff5)
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 
38 	attr.sample_freq = 500;
39 
40 	evlist = perf_evlist__new();
41 	if (evlist == NULL) {
42 		pr_debug("perf_evlist__new\n");
43 		return -1;
44 	}
45 
46 	evsel = perf_evsel__new(&attr);
47 	if (evsel == NULL) {
48 		pr_debug("perf_evsel__new\n");
49 		goto out_delete_evlist;
50 	}
51 	perf_evlist__add(evlist, evsel);
52 
53 	evlist->cpus = cpu_map__dummy_new();
54 	evlist->threads = thread_map__new_by_tid(getpid());
55 	if (!evlist->cpus || !evlist->threads) {
56 		err = -ENOMEM;
57 		pr_debug("Not enough memory to create thread/cpu maps\n");
58 		goto out_delete_evlist;
59 	}
60 
61 	if (perf_evlist__open(evlist)) {
62 		const char *knob = "/proc/sys/kernel/perf_event_max_sample_rate";
63 
64 		err = -errno;
65 		pr_debug("Couldn't open evlist: %s\nHint: check %s, using %" PRIu64 " in this test.\n",
66 			 strerror_r(errno, sbuf, sizeof(sbuf)),
67 			 knob, (u64)attr.sample_freq);
68 		goto out_delete_evlist;
69 	}
70 
71 	err = perf_evlist__mmap(evlist, 128, true);
72 	if (err < 0) {
73 		pr_debug("failed to mmap event: %d (%s)\n", errno,
74 			 strerror_r(errno, sbuf, sizeof(sbuf)));
75 		goto out_delete_evlist;
76 	}
77 
78 	perf_evlist__enable(evlist);
79 
80 	/* collect samples */
81 	for (i = 0; i < NR_LOOPS; i++)
82 		tmp++;
83 
84 	perf_evlist__disable(evlist);
85 
86 	while ((event = perf_evlist__mmap_read(evlist, 0)) != NULL) {
87 		struct perf_sample sample;
88 
89 		if (event->header.type != PERF_RECORD_SAMPLE)
90 			goto next_event;
91 
92 		err = perf_evlist__parse_sample(evlist, event, &sample);
93 		if (err < 0) {
94 			pr_debug("Error during parse sample\n");
95 			goto out_delete_evlist;
96 		}
97 
98 		total_periods += sample.period;
99 		nr_samples++;
100 next_event:
101 		perf_evlist__mmap_consume(evlist, 0);
102 	}
103 
104 	if ((u64) nr_samples == total_periods) {
105 		pr_debug("All (%d) samples have period value of 1!\n",
106 			 nr_samples);
107 		err = -1;
108 	}
109 
110 out_delete_evlist:
111 	perf_evlist__delete(evlist);
112 	return err;
113 }
114 
115 int test__sw_clock_freq(void)
116 {
117 	int ret;
118 
119 	ret = __test__sw_clock_freq(PERF_COUNT_SW_CPU_CLOCK);
120 	if (!ret)
121 		ret = __test__sw_clock_freq(PERF_COUNT_SW_TASK_CLOCK);
122 
123 	return ret;
124 }
125