xref: /openbmc/linux/tools/perf/tests/sw-clock.c (revision 275876e2)
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 	union perf_event *event;
26 	struct perf_evsel *evsel;
27 	struct perf_evlist *evlist;
28 	struct perf_event_attr attr = {
29 		.type = PERF_TYPE_SOFTWARE,
30 		.config = clock_id,
31 		.sample_type = PERF_SAMPLE_PERIOD,
32 		.exclude_kernel = 1,
33 		.disabled = 1,
34 		.freq = 1,
35 	};
36 
37 	attr.sample_freq = 500;
38 
39 	evlist = perf_evlist__new();
40 	if (evlist == NULL) {
41 		pr_debug("perf_evlist__new\n");
42 		return -1;
43 	}
44 
45 	evsel = perf_evsel__new(&attr);
46 	if (evsel == NULL) {
47 		pr_debug("perf_evsel__new\n");
48 		goto out_delete_evlist;
49 	}
50 	perf_evlist__add(evlist, evsel);
51 
52 	evlist->cpus = cpu_map__dummy_new();
53 	evlist->threads = thread_map__new_by_tid(getpid());
54 	if (!evlist->cpus || !evlist->threads) {
55 		err = -ENOMEM;
56 		pr_debug("Not enough memory to create thread/cpu maps\n");
57 		goto out_delete_evlist;
58 	}
59 
60 	if (perf_evlist__open(evlist)) {
61 		const char *knob = "/proc/sys/kernel/perf_event_max_sample_rate";
62 
63 		err = -errno;
64 		pr_debug("Couldn't open evlist: %s\nHint: check %s, using %" PRIu64 " in this test.\n",
65 			 strerror(errno), knob, (u64)attr.sample_freq);
66 		goto out_delete_evlist;
67 	}
68 
69 	err = perf_evlist__mmap(evlist, 128, true);
70 	if (err < 0) {
71 		pr_debug("failed to mmap event: %d (%s)\n", errno,
72 			 strerror(errno));
73 		goto out_delete_evlist;
74 	}
75 
76 	perf_evlist__enable(evlist);
77 
78 	/* collect samples */
79 	for (i = 0; i < NR_LOOPS; i++)
80 		tmp++;
81 
82 	perf_evlist__disable(evlist);
83 
84 	while ((event = perf_evlist__mmap_read(evlist, 0)) != NULL) {
85 		struct perf_sample sample;
86 
87 		if (event->header.type != PERF_RECORD_SAMPLE)
88 			goto next_event;
89 
90 		err = perf_evlist__parse_sample(evlist, event, &sample);
91 		if (err < 0) {
92 			pr_debug("Error during parse sample\n");
93 			goto out_delete_evlist;
94 		}
95 
96 		total_periods += sample.period;
97 		nr_samples++;
98 next_event:
99 		perf_evlist__mmap_consume(evlist, 0);
100 	}
101 
102 	if ((u64) nr_samples == total_periods) {
103 		pr_debug("All (%d) samples have period value of 1!\n",
104 			 nr_samples);
105 		err = -1;
106 	}
107 
108 out_delete_evlist:
109 	perf_evlist__delete(evlist);
110 	return err;
111 }
112 
113 int test__sw_clock_freq(void)
114 {
115 	int ret;
116 
117 	ret = __test__sw_clock_freq(PERF_COUNT_SW_CPU_CLOCK);
118 	if (!ret)
119 		ret = __test__sw_clock_freq(PERF_COUNT_SW_TASK_CLOCK);
120 
121 	return ret;
122 }
123