1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Test backward bit in event attribute, read ring buffer from end to
4 * beginning
5 */
6
7 #include <evlist.h>
8 #include <sys/prctl.h>
9 #include "record.h"
10 #include "tests.h"
11 #include "debug.h"
12 #include "parse-events.h"
13 #include "util/mmap.h"
14 #include <errno.h>
15 #include <linux/string.h>
16 #include <perf/mmap.h>
17
18 #define NR_ITERS 111
19
testcase(void)20 static void testcase(void)
21 {
22 int i;
23
24 for (i = 0; i < NR_ITERS; i++) {
25 char proc_name[15];
26
27 snprintf(proc_name, sizeof(proc_name), "p:%d\n", i);
28 prctl(PR_SET_NAME, proc_name);
29 }
30 }
31
count_samples(struct evlist * evlist,int * sample_count,int * comm_count)32 static int count_samples(struct evlist *evlist, int *sample_count,
33 int *comm_count)
34 {
35 int i;
36
37 for (i = 0; i < evlist->core.nr_mmaps; i++) {
38 struct mmap *map = &evlist->overwrite_mmap[i];
39 union perf_event *event;
40
41 perf_mmap__read_init(&map->core);
42 while ((event = perf_mmap__read_event(&map->core)) != NULL) {
43 const u32 type = event->header.type;
44
45 switch (type) {
46 case PERF_RECORD_SAMPLE:
47 (*sample_count)++;
48 break;
49 case PERF_RECORD_COMM:
50 (*comm_count)++;
51 break;
52 default:
53 pr_err("Unexpected record of type %d\n", type);
54 return TEST_FAIL;
55 }
56 }
57 perf_mmap__read_done(&map->core);
58 }
59 return TEST_OK;
60 }
61
do_test(struct evlist * evlist,int mmap_pages,int * sample_count,int * comm_count)62 static int do_test(struct evlist *evlist, int mmap_pages,
63 int *sample_count, int *comm_count)
64 {
65 int err;
66 char sbuf[STRERR_BUFSIZE];
67
68 err = evlist__mmap(evlist, mmap_pages);
69 if (err < 0) {
70 pr_debug("evlist__mmap: %s\n",
71 str_error_r(errno, sbuf, sizeof(sbuf)));
72 return TEST_FAIL;
73 }
74
75 evlist__enable(evlist);
76 testcase();
77 evlist__disable(evlist);
78
79 err = count_samples(evlist, sample_count, comm_count);
80 evlist__munmap(evlist);
81 return err;
82 }
83
84
test__backward_ring_buffer(struct test_suite * test __maybe_unused,int subtest __maybe_unused)85 static int test__backward_ring_buffer(struct test_suite *test __maybe_unused, int subtest __maybe_unused)
86 {
87 int ret = TEST_SKIP, err, sample_count = 0, comm_count = 0;
88 char pid[16], sbuf[STRERR_BUFSIZE];
89 struct evlist *evlist;
90 struct evsel *evsel __maybe_unused;
91 struct parse_events_error parse_error;
92 struct record_opts opts = {
93 .target = {
94 .uses_mmap = true,
95 },
96 .freq = 0,
97 .mmap_pages = 256,
98 .default_interval = 1,
99 };
100
101 snprintf(pid, sizeof(pid), "%d", getpid());
102 pid[sizeof(pid) - 1] = '\0';
103 opts.target.tid = opts.target.pid = pid;
104
105 evlist = evlist__new();
106 if (!evlist) {
107 pr_debug("Not enough memory to create evlist\n");
108 return TEST_FAIL;
109 }
110
111 err = evlist__create_maps(evlist, &opts.target);
112 if (err < 0) {
113 pr_debug("Not enough memory to create thread/cpu maps\n");
114 goto out_delete_evlist;
115 }
116
117 parse_events_error__init(&parse_error);
118 /*
119 * Set backward bit, ring buffer should be writing from end. Record
120 * it in aux evlist
121 */
122 err = parse_events(evlist, "syscalls:sys_enter_prctl/overwrite/", &parse_error);
123 parse_events_error__exit(&parse_error);
124 if (err) {
125 pr_debug("Failed to parse tracepoint event, try use root\n");
126 ret = TEST_SKIP;
127 goto out_delete_evlist;
128 }
129
130 evlist__config(evlist, &opts, NULL);
131
132 err = evlist__open(evlist);
133 if (err < 0) {
134 pr_debug("perf_evlist__open: %s\n",
135 str_error_r(errno, sbuf, sizeof(sbuf)));
136 goto out_delete_evlist;
137 }
138
139 ret = TEST_FAIL;
140 err = do_test(evlist, opts.mmap_pages, &sample_count,
141 &comm_count);
142 if (err != TEST_OK)
143 goto out_delete_evlist;
144
145 if ((sample_count != NR_ITERS) || (comm_count != NR_ITERS)) {
146 pr_err("Unexpected counter: sample_count=%d, comm_count=%d\n",
147 sample_count, comm_count);
148 goto out_delete_evlist;
149 }
150
151 evlist__close(evlist);
152
153 err = evlist__open(evlist);
154 if (err < 0) {
155 pr_debug("perf_evlist__open: %s\n",
156 str_error_r(errno, sbuf, sizeof(sbuf)));
157 goto out_delete_evlist;
158 }
159
160 err = do_test(evlist, 1, &sample_count, &comm_count);
161 if (err != TEST_OK)
162 goto out_delete_evlist;
163
164 ret = TEST_OK;
165 out_delete_evlist:
166 evlist__delete(evlist);
167 return ret;
168 }
169
170 DEFINE_SUITE("Read backward ring buffer", backward_ring_buffer);
171