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