Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0
2#include <errno.h>
3#include <inttypes.h>
4/* For the CLR_() macros */
5#include <pthread.h>
6#include <stdlib.h>
7#include <perf/cpumap.h>
8
9#include "debug.h"
10#include "evlist.h"
11#include "evsel.h"
12#include "thread_map.h"
13#include "tests.h"
14#include "util/mmap.h"
15#include <linux/err.h>
16#include <linux/kernel.h>
17#include <linux/string.h>
18#include <perf/evlist.h>
19#include <perf/mmap.h>
20
21/*
22 * This test will generate random numbers of calls to some getpid syscalls,
23 * then establish an mmap for a group of events that are created to monitor
24 * the syscalls.
25 *
26 * It will receive the events, using mmap, use its PERF_SAMPLE_ID generated
27 * sample.id field to map back to its respective perf_evsel instance.
28 *
29 * Then it checks if the number of syscalls reported as perf events by
30 * the kernel corresponds to the number of syscalls made.
31 */
32static int test__basic_mmap(struct test_suite *test __maybe_unused, int subtest __maybe_unused)
33{
34 int err = -1;
35 union perf_event *event;
36 struct perf_thread_map *threads;
37 struct perf_cpu_map *cpus;
38 struct evlist *evlist;
39 cpu_set_t cpu_set;
40 const char *syscall_names[] = { "getsid", "getppid", "getpgid", };
41 pid_t (*syscalls[])(void) = { (void *)getsid, getppid, (void*)getpgid };
42#define nsyscalls ARRAY_SIZE(syscall_names)
43 unsigned int nr_events[nsyscalls],
44 expected_nr_events[nsyscalls], i, j;
45 struct evsel *evsels[nsyscalls], *evsel;
46 char sbuf[STRERR_BUFSIZE];
47 struct mmap *md;
48
49 threads = thread_map__new(-1, getpid(), UINT_MAX);
50 if (threads == NULL) {
51 pr_debug("thread_map__new\n");
52 return -1;
53 }
54
55 cpus = perf_cpu_map__new(NULL);
56 if (cpus == NULL) {
57 pr_debug("perf_cpu_map__new\n");
58 goto out_free_threads;
59 }
60
61 CPU_ZERO(&cpu_set);
62 CPU_SET(perf_cpu_map__cpu(cpus, 0).cpu, &cpu_set);
63 sched_setaffinity(0, sizeof(cpu_set), &cpu_set);
64 if (sched_setaffinity(0, sizeof(cpu_set), &cpu_set) < 0) {
65 pr_debug("sched_setaffinity() failed on CPU %d: %s ",
66 perf_cpu_map__cpu(cpus, 0).cpu,
67 str_error_r(errno, sbuf, sizeof(sbuf)));
68 goto out_free_cpus;
69 }
70
71 evlist = evlist__new();
72 if (evlist == NULL) {
73 pr_debug("evlist__new\n");
74 goto out_free_cpus;
75 }
76
77 perf_evlist__set_maps(&evlist->core, cpus, threads);
78
79 for (i = 0; i < nsyscalls; ++i) {
80 char name[64];
81
82 snprintf(name, sizeof(name), "sys_enter_%s", syscall_names[i]);
83 evsels[i] = evsel__newtp("syscalls", name);
84 if (IS_ERR(evsels[i])) {
85 pr_debug("evsel__new(%s)\n", name);
86 goto out_delete_evlist;
87 }
88
89 evsels[i]->core.attr.wakeup_events = 1;
90 evsel__set_sample_id(evsels[i], false);
91
92 evlist__add(evlist, evsels[i]);
93
94 if (evsel__open(evsels[i], cpus, threads) < 0) {
95 pr_debug("failed to open counter: %s, "
96 "tweak /proc/sys/kernel/perf_event_paranoid?\n",
97 str_error_r(errno, sbuf, sizeof(sbuf)));
98 goto out_delete_evlist;
99 }
100
101 nr_events[i] = 0;
102 expected_nr_events[i] = 1 + rand() % 127;
103 }
104
105 if (evlist__mmap(evlist, 128) < 0) {
106 pr_debug("failed to mmap events: %d (%s)\n", errno,
107 str_error_r(errno, sbuf, sizeof(sbuf)));
108 goto out_delete_evlist;
109 }
110
111 for (i = 0; i < nsyscalls; ++i)
112 for (j = 0; j < expected_nr_events[i]; ++j) {
113 int foo = syscalls[i]();
114 ++foo;
115 }
116
117 md = &evlist->mmap[0];
118 if (perf_mmap__read_init(&md->core) < 0)
119 goto out_init;
120
121 while ((event = perf_mmap__read_event(&md->core)) != NULL) {
122 struct perf_sample sample;
123
124 if (event->header.type != PERF_RECORD_SAMPLE) {
125 pr_debug("unexpected %s event\n",
126 perf_event__name(event->header.type));
127 goto out_delete_evlist;
128 }
129
130 err = evlist__parse_sample(evlist, event, &sample);
131 if (err) {
132 pr_err("Can't parse sample, err = %d\n", err);
133 goto out_delete_evlist;
134 }
135
136 err = -1;
137 evsel = evlist__id2evsel(evlist, sample.id);
138 if (evsel == NULL) {
139 pr_debug("event with id %" PRIu64
140 " doesn't map to an evsel\n", sample.id);
141 goto out_delete_evlist;
142 }
143 nr_events[evsel->core.idx]++;
144 perf_mmap__consume(&md->core);
145 }
146 perf_mmap__read_done(&md->core);
147
148out_init:
149 err = 0;
150 evlist__for_each_entry(evlist, evsel) {
151 if (nr_events[evsel->core.idx] != expected_nr_events[evsel->core.idx]) {
152 pr_debug("expected %d %s events, got %d\n",
153 expected_nr_events[evsel->core.idx],
154 evsel__name(evsel), nr_events[evsel->core.idx]);
155 err = -1;
156 goto out_delete_evlist;
157 }
158 }
159
160out_delete_evlist:
161 evlist__delete(evlist);
162out_free_cpus:
163 perf_cpu_map__put(cpus);
164out_free_threads:
165 perf_thread_map__put(threads);
166 return err;
167}
168
169DEFINE_SUITE("Read samples using the mmap interface", basic_mmap);