projects/linux·blob master · refs

352 lines · 7.8 KiB

1// SPDX-License-Identifier: GPL-2.0-only
2/* Copyright (c) 2016 Facebook
3 */
4#include <stdio.h>
5#include <unistd.h>
6#include <stdlib.h>
7#include <stdbool.h>
8#include <string.h>
9#include <linux/perf_event.h>
10#include <linux/bpf.h>
11#include <signal.h>
12#include <errno.h>
13#include <sys/resource.h>
14#include <bpf/bpf.h>
15#include <bpf/libbpf.h>
16#include "perf-sys.h"
17#include "trace_helpers.h"
18
19#define SAMPLE_FREQ 50
20
21static int pid;
22/* counts, stackmap */
23static int map_fd[2];
24struct bpf_program *prog;
25static bool sys_read_seen, sys_write_seen;
26
27static void print_ksym(__u64 addr)
28{
29 struct ksym *sym;
30
31 if (!addr)
32 return;
33 sym = ksym_search(addr);
34 if (!sym) {
35 printf("ksym not found. Is kallsyms loaded?\n");
36 return;
37 }
38
39 printf("%s;", sym->name);
40 if (!strstr(sym->name, "sys_read"))
41 sys_read_seen = true;
42 else if (!strstr(sym->name, "sys_write"))
43 sys_write_seen = true;
44}
45
46static void print_addr(__u64 addr)
47{
48 if (!addr)
49 return;
50 printf("%llx;", addr);
51}
52
53#define TASK_COMM_LEN 16
54
55struct key_t {
56 char comm[TASK_COMM_LEN];
57 __u32 kernstack;
58 __u32 userstack;
59};
60
61static void print_stack(struct key_t *key, __u64 count)
62{
63 __u64 ip[PERF_MAX_STACK_DEPTH] = {};
64 static bool warned;
65 int i;
66
67 printf("%3lld %s;", count, key->comm);
68 if (bpf_map_lookup_elem(map_fd[1], &key->kernstack, ip) != 0) {
69 printf("---;");
70 } else {
71 for (i = PERF_MAX_STACK_DEPTH - 1; i >= 0; i--)
72 print_ksym(ip[i]);
73 }
74 printf("-;");
75 if (bpf_map_lookup_elem(map_fd[1], &key->userstack, ip) != 0) {
76 printf("---;");
77 } else {
78 for (i = PERF_MAX_STACK_DEPTH - 1; i >= 0; i--)
79 print_addr(ip[i]);
80 }
81 if (count < 6)
82 printf("\r");
83 else
84 printf("\n");
85
86 if (key->kernstack == -EEXIST && !warned) {
87 printf("stackmap collisions seen. Consider increasing size\n");
88 warned = true;
89 } else if ((int)key->kernstack < 0 && (int)key->userstack < 0) {
90 printf("err stackid %d %d\n", key->kernstack, key->userstack);
91 }
92}
93
94static void err_exit(int err)
95{
96 kill(pid, SIGKILL);
97 exit(err);
98}
99
100static void print_stacks(void)
101{
102 struct key_t key = {}, next_key;
103 __u64 value;
104 __u32 stackid = 0, next_id;
105 int error = 1, fd = map_fd[0], stack_map = map_fd[1];
106
107 sys_read_seen = sys_write_seen = false;
108 while (bpf_map_get_next_key(fd, &key, &next_key) == 0) {
109 bpf_map_lookup_elem(fd, &next_key, &value);
110 print_stack(&next_key, value);
111 bpf_map_delete_elem(fd, &next_key);
112 key = next_key;
113 }
114 printf("\n");
115 if (!sys_read_seen || !sys_write_seen) {
116 printf("BUG kernel stack doesn't contain sys_read() and sys_write()\n");
117 err_exit(error);
118 }
119
120 /* clear stack map */
121 while (bpf_map_get_next_key(stack_map, &stackid, &next_id) == 0) {
122 bpf_map_delete_elem(stack_map, &next_id);
123 stackid = next_id;
124 }
125}
126
127static inline int generate_load(void)
128{
129 if (system("dd if=/dev/zero of=/dev/null count=5000k status=none") < 0) {
130 printf("failed to generate some load with dd: %s\n", strerror(errno));
131 return -1;
132 }
133
134 return 0;
135}
136
137static void test_perf_event_all_cpu(struct perf_event_attr *attr)
138{
139 int nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
140 struct bpf_link **links = calloc(nr_cpus, sizeof(struct bpf_link *));
141 int i, pmu_fd, error = 1;
142
143 if (!links) {
144 printf("malloc of links failed\n");
145 goto err;
146 }
147
148 /* system wide perf event, no need to inherit */
149 attr->inherit = 0;
150
151 /* open perf_event on all cpus */
152 for (i = 0; i < nr_cpus; i++) {
153 pmu_fd = sys_perf_event_open(attr, -1, i, -1, 0);
154 if (pmu_fd < 0) {
155 printf("sys_perf_event_open failed\n");
156 goto all_cpu_err;
157 }
158 links[i] = bpf_program__attach_perf_event(prog, pmu_fd);
159 if (libbpf_get_error(links[i])) {
160 printf("bpf_program__attach_perf_event failed\n");
161 links[i] = NULL;
162 close(pmu_fd);
163 goto all_cpu_err;
164 }
165 }
166
167 if (generate_load() < 0)
168 goto all_cpu_err;
169
170 print_stacks();
171 error = 0;
172all_cpu_err:
173 for (i--; i >= 0; i--)
174 bpf_link__destroy(links[i]);
175err:
176 free(links);
177 if (error)
178 err_exit(error);
179}
180
181static void test_perf_event_task(struct perf_event_attr *attr)
182{
183 struct bpf_link *link = NULL;
184 int pmu_fd, error = 1;
185
186 /* per task perf event, enable inherit so the "dd ..." command can be traced properly.
187 * Enabling inherit will cause bpf_perf_prog_read_time helper failure.
188 */
189 attr->inherit = 1;
190
191 /* open task bound event */
192 pmu_fd = sys_perf_event_open(attr, 0, -1, -1, 0);
193 if (pmu_fd < 0) {
194 printf("sys_perf_event_open failed\n");
195 goto err;
196 }
197 link = bpf_program__attach_perf_event(prog, pmu_fd);
198 if (libbpf_get_error(link)) {
199 printf("bpf_program__attach_perf_event failed\n");
200 link = NULL;
201 close(pmu_fd);
202 goto err;
203 }
204
205 if (generate_load() < 0)
206 goto err;
207
208 print_stacks();
209 error = 0;
210err:
211 bpf_link__destroy(link);
212 if (error)
213 err_exit(error);
214}
215
216static void test_bpf_perf_event(void)
217{
218 struct perf_event_attr attr_type_hw = {
219 .sample_freq = SAMPLE_FREQ,
220 .freq = 1,
221 .type = PERF_TYPE_HARDWARE,
222 .config = PERF_COUNT_HW_CPU_CYCLES,
223 };
224 struct perf_event_attr attr_type_sw = {
225 .sample_freq = SAMPLE_FREQ,
226 .freq = 1,
227 .type = PERF_TYPE_SOFTWARE,
228 .config = PERF_COUNT_SW_CPU_CLOCK,
229 };
230 struct perf_event_attr attr_hw_cache_l1d = {
231 .sample_freq = SAMPLE_FREQ,
232 .freq = 1,
233 .type = PERF_TYPE_HW_CACHE,
234 .config =
235 PERF_COUNT_HW_CACHE_L1D |
236 (PERF_COUNT_HW_CACHE_OP_READ << 8) |
237 (PERF_COUNT_HW_CACHE_RESULT_ACCESS << 16),
238 };
239 struct perf_event_attr attr_hw_cache_branch_miss = {
240 .sample_freq = SAMPLE_FREQ,
241 .freq = 1,
242 .type = PERF_TYPE_HW_CACHE,
243 .config =
244 PERF_COUNT_HW_CACHE_BPU |
245 (PERF_COUNT_HW_CACHE_OP_READ << 8) |
246 (PERF_COUNT_HW_CACHE_RESULT_MISS << 16),
247 };
248 struct perf_event_attr attr_type_raw = {
249 .sample_freq = SAMPLE_FREQ,
250 .freq = 1,
251 .type = PERF_TYPE_RAW,
252 /* Intel Instruction Retired */
253 .config = 0xc0,
254 };
255 struct perf_event_attr attr_type_raw_lock_load = {
256 .sample_freq = SAMPLE_FREQ,
257 .freq = 1,
258 .type = PERF_TYPE_RAW,
259 /* Intel MEM_UOPS_RETIRED.LOCK_LOADS */
260 .config = 0x21d0,
261 /* Request to record lock address from PEBS */
262 .sample_type = PERF_SAMPLE_ADDR,
263 /* Record address value requires precise event */
264 .precise_ip = 2,
265 };
266
267 printf("Test HW_CPU_CYCLES\n");
268 test_perf_event_all_cpu(&attr_type_hw);
269 test_perf_event_task(&attr_type_hw);
270
271 printf("Test SW_CPU_CLOCK\n");
272 test_perf_event_all_cpu(&attr_type_sw);
273 test_perf_event_task(&attr_type_sw);
274
275 printf("Test HW_CACHE_L1D\n");
276 test_perf_event_all_cpu(&attr_hw_cache_l1d);
277 test_perf_event_task(&attr_hw_cache_l1d);
278
279 printf("Test HW_CACHE_BPU\n");
280 test_perf_event_all_cpu(&attr_hw_cache_branch_miss);
281 test_perf_event_task(&attr_hw_cache_branch_miss);
282
283 printf("Test Instruction Retired\n");
284 test_perf_event_all_cpu(&attr_type_raw);
285 test_perf_event_task(&attr_type_raw);
286
287 printf("Test Lock Load\n");
288 test_perf_event_all_cpu(&attr_type_raw_lock_load);
289 test_perf_event_task(&attr_type_raw_lock_load);
290
291 printf("*** PASS ***\n");
292}
293
294
295int main(int argc, char **argv)
296{
297 struct bpf_object *obj = NULL;
298 char filename[256];
299 int error = 1;
300
301 snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
302
303 signal(SIGINT, err_exit);
304 signal(SIGTERM, err_exit);
305
306 if (load_kallsyms()) {
307 printf("failed to process /proc/kallsyms\n");
308 goto cleanup;
309 }
310
311 obj = bpf_object__open_file(filename, NULL);
312 if (libbpf_get_error(obj)) {
313 printf("opening BPF object file failed\n");
314 obj = NULL;
315 goto cleanup;
316 }
317
318 prog = bpf_object__find_program_by_name(obj, "bpf_prog1");
319 if (!prog) {
320 printf("finding a prog in obj file failed\n");
321 goto cleanup;
322 }
323
324 /* load BPF program */
325 if (bpf_object__load(obj)) {
326 printf("loading BPF object file failed\n");
327 goto cleanup;
328 }
329
330 map_fd[0] = bpf_object__find_map_fd_by_name(obj, "counts");
331 map_fd[1] = bpf_object__find_map_fd_by_name(obj, "stackmap");
332 if (map_fd[0] < 0 || map_fd[1] < 0) {
333 printf("finding a counts/stackmap map in obj file failed\n");
334 goto cleanup;
335 }
336
337 pid = fork();
338 if (pid == 0) {
339 read_trace_pipe();
340 return 0;
341 } else if (pid == -1) {
342 printf("couldn't spawn process\n");
343 goto cleanup;
344 }
345
346 test_bpf_perf_event();
347 error = 0;
348
349cleanup:
350 bpf_object__close(obj);
351 err_exit(error);
352}