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/*
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
16static 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
28static 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 u64 start, end;
37
38 perf_mmap__read_init(map, true, &start, &end);
39 while ((event = perf_mmap__read_event(map, true, &start, end)) != NULL) {
40 const u32 type = event->header.type;
41
42 switch (type) {
43 case PERF_RECORD_SAMPLE:
44 (*sample_count)++;
45 break;
46 case PERF_RECORD_COMM:
47 (*comm_count)++;
48 break;
49 default:
50 pr_err("Unexpected record of type %d\n", type);
51 return TEST_FAIL;
52 }
53 }
54 perf_mmap__read_done(map);
55 }
56 return TEST_OK;
57}
58
59static int do_test(struct perf_evlist *evlist, int mmap_pages,
60 int *sample_count, int *comm_count)
61{
62 int err;
63 char sbuf[STRERR_BUFSIZE];
64
65 err = perf_evlist__mmap(evlist, mmap_pages);
66 if (err < 0) {
67 pr_debug("perf_evlist__mmap: %s\n",
68 str_error_r(errno, sbuf, sizeof(sbuf)));
69 return TEST_FAIL;
70 }
71
72 perf_evlist__enable(evlist);
73 testcase();
74 perf_evlist__disable(evlist);
75
76 err = count_samples(evlist, sample_count, comm_count);
77 perf_evlist__munmap(evlist);
78 return err;
79}
80
81
82int test__backward_ring_buffer(struct test *test __maybe_unused, int subtest __maybe_unused)
83{
84 int ret = TEST_SKIP, err, sample_count = 0, comm_count = 0;
85 char pid[16], sbuf[STRERR_BUFSIZE];
86 struct perf_evlist *evlist;
87 struct perf_evsel *evsel __maybe_unused;
88 struct parse_events_error parse_error;
89 struct record_opts opts = {
90 .target = {
91 .uid = UINT_MAX,
92 .uses_mmap = true,
93 },
94 .freq = 0,
95 .mmap_pages = 256,
96 .default_interval = 1,
97 };
98
99 snprintf(pid, sizeof(pid), "%d", getpid());
100 pid[sizeof(pid) - 1] = '\0';
101 opts.target.tid = opts.target.pid = pid;
102
103 evlist = perf_evlist__new();
104 if (!evlist) {
105 pr_debug("Not enough memory to create evlist\n");
106 return TEST_FAIL;
107 }
108
109 err = perf_evlist__create_maps(evlist, &opts.target);
110 if (err < 0) {
111 pr_debug("Not enough memory to create thread/cpu maps\n");
112 goto out_delete_evlist;
113 }
114
115 bzero(&parse_error, sizeof(parse_error));
116 /*
117 * Set backward bit, ring buffer should be writing from end. Record
118 * it in aux evlist
119 */
120 err = parse_events(evlist, "syscalls:sys_enter_prctl/overwrite/", &parse_error);
121 if (err) {
122 pr_debug("Failed to parse tracepoint event, try use root\n");
123 ret = TEST_SKIP;
124 goto out_delete_evlist;
125 }
126
127 perf_evlist__config(evlist, &opts, NULL);
128
129 err = perf_evlist__open(evlist);
130 if (err < 0) {
131 pr_debug("perf_evlist__open: %s\n",
132 str_error_r(errno, sbuf, sizeof(sbuf)));
133 goto out_delete_evlist;
134 }
135
136 ret = TEST_FAIL;
137 err = do_test(evlist, opts.mmap_pages, &sample_count,
138 &comm_count);
139 if (err != TEST_OK)
140 goto out_delete_evlist;
141
142 if ((sample_count != NR_ITERS) || (comm_count != NR_ITERS)) {
143 pr_err("Unexpected counter: sample_count=%d, comm_count=%d\n",
144 sample_count, comm_count);
145 goto out_delete_evlist;
146 }
147
148 err = do_test(evlist, 1, &sample_count, &comm_count);
149 if (err != TEST_OK)
150 goto out_delete_evlist;
151
152 ret = TEST_OK;
153out_delete_evlist:
154 perf_evlist__delete(evlist);
155 return ret;
156}