1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * intel_tpebs.c: Intel TPEBS support 4 */ 5 6 7 #include <sys/param.h> 8 #include <subcmd/run-command.h> 9 #include <thread.h> 10 #include "intel-tpebs.h" 11 #include <linux/list.h> 12 #include <linux/zalloc.h> 13 #include <linux/err.h> 14 #include "sample.h" 15 #include "debug.h" 16 #include "evlist.h" 17 #include "evsel.h" 18 #include "session.h" 19 #include "tool.h" 20 #include "cpumap.h" 21 #include "metricgroup.h" 22 #include <sys/stat.h> 23 #include <sys/file.h> 24 #include <poll.h> 25 #include <math.h> 26 27 #define PERF_DATA "-" 28 29 bool tpebs_recording; 30 static pid_t tpebs_pid = -1; 31 static size_t tpebs_event_size; 32 static LIST_HEAD(tpebs_results); 33 static pthread_t tpebs_reader_thread; 34 static struct child_process *tpebs_cmd; 35 36 struct tpebs_retire_lat { 37 struct list_head nd; 38 /* Event name */ 39 const char *name; 40 /* Event name with the TPEBS modifier R */ 41 const char *tpebs_name; 42 /* Count of retire_latency values found in sample data */ 43 size_t count; 44 /* Sum of all the retire_latency values in sample data */ 45 int sum; 46 /* Average of retire_latency, val = sum / count */ 47 double val; 48 }; 49 50 static int get_perf_record_args(const char **record_argv, char buf[], 51 const char *cpumap_buf) 52 { 53 struct tpebs_retire_lat *e; 54 int i = 0; 55 56 pr_debug("tpebs: Prepare perf record for retire_latency\n"); 57 58 record_argv[i++] = "perf"; 59 record_argv[i++] = "record"; 60 record_argv[i++] = "-W"; 61 record_argv[i++] = "--synth=no"; 62 record_argv[i++] = buf; 63 64 if (!cpumap_buf) { 65 pr_err("tpebs: Require cpumap list to run sampling\n"); 66 return -ECANCELED; 67 } 68 /* Use -C when cpumap_buf is not "-1" */ 69 if (strcmp(cpumap_buf, "-1")) { 70 record_argv[i++] = "-C"; 71 record_argv[i++] = cpumap_buf; 72 } 73 74 list_for_each_entry(e, &tpebs_results, nd) { 75 record_argv[i++] = "-e"; 76 record_argv[i++] = e->name; 77 } 78 79 record_argv[i++] = "-o"; 80 record_argv[i++] = PERF_DATA; 81 82 return 0; 83 } 84 85 static int prepare_run_command(const char **argv) 86 { 87 tpebs_cmd = zalloc(sizeof(struct child_process)); 88 if (!tpebs_cmd) 89 return -ENOMEM; 90 tpebs_cmd->argv = argv; 91 tpebs_cmd->out = -1; 92 return 0; 93 } 94 95 static int start_perf_record(int control_fd[], int ack_fd[], 96 const char *cpumap_buf) 97 { 98 const char **record_argv; 99 int ret; 100 char buf[32]; 101 102 scnprintf(buf, sizeof(buf), "--control=fd:%d,%d", control_fd[0], ack_fd[1]); 103 104 record_argv = calloc(12 + 2 * tpebs_event_size, sizeof(char *)); 105 if (!record_argv) 106 return -ENOMEM; 107 108 ret = get_perf_record_args(record_argv, buf, cpumap_buf); 109 if (ret) 110 goto out; 111 112 ret = prepare_run_command(record_argv); 113 if (ret) 114 goto out; 115 ret = start_command(tpebs_cmd); 116 out: 117 free(record_argv); 118 return ret; 119 } 120 121 static int process_sample_event(const struct perf_tool *tool __maybe_unused, 122 union perf_event *event __maybe_unused, 123 struct perf_sample *sample, 124 struct evsel *evsel, 125 struct machine *machine __maybe_unused) 126 { 127 int ret = 0; 128 const char *evname; 129 struct tpebs_retire_lat *t; 130 131 evname = evsel__name(evsel); 132 133 /* 134 * Need to handle per core results? We are assuming average retire 135 * latency value will be used. Save the number of samples and the sum of 136 * retire latency value for each event. 137 */ 138 list_for_each_entry(t, &tpebs_results, nd) { 139 if (!strcmp(evname, t->name)) { 140 t->count += 1; 141 t->sum += sample->retire_lat; 142 t->val = (double) t->sum / t->count; 143 break; 144 } 145 } 146 147 return ret; 148 } 149 150 static int process_feature_event(struct perf_session *session, 151 union perf_event *event) 152 { 153 if (event->feat.feat_id < HEADER_LAST_FEATURE) 154 return perf_event__process_feature(session, event); 155 return 0; 156 } 157 158 static void *__sample_reader(void *arg) 159 { 160 struct child_process *child = arg; 161 struct perf_session *session; 162 struct perf_data data = { 163 .mode = PERF_DATA_MODE_READ, 164 .path = PERF_DATA, 165 .file.fd = child->out, 166 }; 167 struct perf_tool tool; 168 169 perf_tool__init(&tool, /*ordered_events=*/false); 170 tool.sample = process_sample_event; 171 tool.feature = process_feature_event; 172 tool.attr = perf_event__process_attr; 173 174 session = perf_session__new(&data, &tool); 175 if (IS_ERR(session)) 176 return NULL; 177 perf_session__process_events(session); 178 perf_session__delete(session); 179 180 return NULL; 181 } 182 183 /* 184 * tpebs_stop - stop the sample data read thread and the perf record process. 185 */ 186 static int tpebs_stop(void) 187 { 188 int ret = 0; 189 190 /* Like tpebs_start, we should only run tpebs_end once. */ 191 if (tpebs_pid != -1) { 192 kill(tpebs_cmd->pid, SIGTERM); 193 tpebs_pid = -1; 194 pthread_join(tpebs_reader_thread, NULL); 195 close(tpebs_cmd->out); 196 ret = finish_command(tpebs_cmd); 197 if (ret == -ERR_RUN_COMMAND_WAITPID_SIGNAL) 198 ret = 0; 199 } 200 return ret; 201 } 202 203 /* 204 * tpebs_start - start tpebs execution. 205 * @evsel_list: retire_latency evsels in this list will be selected and sampled 206 * to get the average retire_latency value. 207 * 208 * This function will be called from evlist level later when evlist__open() is 209 * called consistently. 210 */ 211 int tpebs_start(struct evlist *evsel_list) 212 { 213 int ret = 0; 214 struct evsel *evsel; 215 char cpumap_buf[50]; 216 217 /* 218 * We should only run tpebs_start when tpebs_recording is enabled. 219 * And we should only run it once with all the required events. 220 */ 221 if (tpebs_pid != -1 || !tpebs_recording) 222 return 0; 223 224 cpu_map__snprint(evsel_list->core.user_requested_cpus, cpumap_buf, sizeof(cpumap_buf)); 225 /* 226 * Prepare perf record for sampling event retire_latency before fork and 227 * prepare workload 228 */ 229 evlist__for_each_entry(evsel_list, evsel) { 230 int i; 231 char *name; 232 struct tpebs_retire_lat *new; 233 234 if (!evsel->retire_lat) 235 continue; 236 237 pr_debug("tpebs: Retire_latency of event %s is required\n", evsel->name); 238 for (i = strlen(evsel->name) - 1; i > 0; i--) { 239 if (evsel->name[i] == 'R') 240 break; 241 } 242 if (i <= 0 || evsel->name[i] != 'R') { 243 ret = -1; 244 goto err; 245 } 246 247 name = strdup(evsel->name); 248 if (!name) { 249 ret = -ENOMEM; 250 goto err; 251 } 252 name[i] = 'p'; 253 254 new = zalloc(sizeof(*new)); 255 if (!new) { 256 ret = -1; 257 zfree(name); 258 goto err; 259 } 260 new->name = name; 261 new->tpebs_name = evsel->name; 262 list_add_tail(&new->nd, &tpebs_results); 263 tpebs_event_size += 1; 264 } 265 266 if (tpebs_event_size > 0) { 267 struct pollfd pollfd = { .events = POLLIN, }; 268 int control_fd[2], ack_fd[2], len; 269 char ack_buf[8]; 270 271 /*Create control and ack fd for --control*/ 272 if (pipe(control_fd) < 0) { 273 pr_err("tpebs: Failed to create control fifo"); 274 ret = -1; 275 goto out; 276 } 277 if (pipe(ack_fd) < 0) { 278 pr_err("tpebs: Failed to create control fifo"); 279 ret = -1; 280 goto out; 281 } 282 283 ret = start_perf_record(control_fd, ack_fd, cpumap_buf); 284 if (ret) 285 goto out; 286 tpebs_pid = tpebs_cmd->pid; 287 if (pthread_create(&tpebs_reader_thread, NULL, __sample_reader, tpebs_cmd)) { 288 kill(tpebs_cmd->pid, SIGTERM); 289 close(tpebs_cmd->out); 290 pr_err("Could not create thread to process sample data.\n"); 291 ret = -1; 292 goto out; 293 } 294 /* Wait for perf record initialization.*/ 295 len = strlen(EVLIST_CTL_CMD_ENABLE_TAG); 296 ret = write(control_fd[1], EVLIST_CTL_CMD_ENABLE_TAG, len); 297 if (ret != len) { 298 pr_err("perf record control write control message failed\n"); 299 goto out; 300 } 301 302 /* wait for an ack */ 303 pollfd.fd = ack_fd[0]; 304 305 /* 306 * We need this poll to ensure the ack_fd PIPE will not hang 307 * when perf record failed for any reason. The timeout value 308 * 3000ms is an empirical selection. 309 */ 310 if (!poll(&pollfd, 1, 3000)) { 311 pr_err("tpebs failed: perf record ack timeout\n"); 312 ret = -1; 313 goto out; 314 } 315 316 if (!(pollfd.revents & POLLIN)) { 317 pr_err("tpebs failed: did not received an ack\n"); 318 ret = -1; 319 goto out; 320 } 321 322 ret = read(ack_fd[0], ack_buf, sizeof(ack_buf)); 323 if (ret > 0) 324 ret = strcmp(ack_buf, EVLIST_CTL_CMD_ACK_TAG); 325 else { 326 pr_err("tpebs: perf record control ack failed\n"); 327 goto out; 328 } 329 out: 330 close(control_fd[0]); 331 close(control_fd[1]); 332 close(ack_fd[0]); 333 close(ack_fd[1]); 334 } 335 err: 336 if (ret) 337 tpebs_delete(); 338 return ret; 339 } 340 341 342 int tpebs_set_evsel(struct evsel *evsel, int cpu_map_idx, int thread) 343 { 344 __u64 val; 345 bool found = false; 346 struct tpebs_retire_lat *t; 347 struct perf_counts_values *count; 348 349 /* Non reitre_latency evsel should never enter this function. */ 350 if (!evsel__is_retire_lat(evsel)) 351 return -1; 352 353 /* 354 * Need to stop the forked record to ensure get sampled data from the 355 * PIPE to process and get non-zero retire_lat value for hybrid. 356 */ 357 tpebs_stop(); 358 count = perf_counts(evsel->counts, cpu_map_idx, thread); 359 360 list_for_each_entry(t, &tpebs_results, nd) { 361 if (t->tpebs_name == evsel->name || 362 (evsel->metric_id && !strcmp(t->tpebs_name, evsel->metric_id))) { 363 found = true; 364 break; 365 } 366 } 367 368 /* Set ena and run to non-zero */ 369 count->ena = count->run = 1; 370 count->lost = 0; 371 372 if (!found) { 373 /* 374 * Set default value or 0 when retire_latency for this event is 375 * not found from sampling data (record_tpebs not set or 0 376 * sample recorded). 377 */ 378 count->val = 0; 379 return 0; 380 } 381 382 /* 383 * Only set retire_latency value to the first CPU and thread. 384 */ 385 if (cpu_map_idx == 0 && thread == 0) 386 val = rint(t->val); 387 else 388 val = 0; 389 390 count->val = val; 391 return 0; 392 } 393 394 static void tpebs_retire_lat__delete(struct tpebs_retire_lat *r) 395 { 396 zfree(&r->name); 397 free(r); 398 } 399 400 401 /* 402 * tpebs_delete - delete tpebs related data and stop the created thread and 403 * process by calling tpebs_stop(). 404 * 405 * This function is called from evlist_delete() and also from builtin-stat 406 * stat_handle_error(). If tpebs_start() is called from places other then perf 407 * stat, need to ensure tpebs_delete() is also called to safely free mem and 408 * close the data read thread and the forked perf record process. 409 * 410 * This function is also called in evsel__close() to be symmetric with 411 * tpebs_start() being called in evsel__open(). We will update this call site 412 * when move tpebs_start() to evlist level. 413 */ 414 void tpebs_delete(void) 415 { 416 struct tpebs_retire_lat *r, *rtmp; 417 418 if (tpebs_pid == -1) 419 return; 420 421 tpebs_stop(); 422 423 list_for_each_entry_safe(r, rtmp, &tpebs_results, nd) { 424 list_del_init(&r->nd); 425 tpebs_retire_lat__delete(r); 426 } 427 428 if (tpebs_cmd) { 429 free(tpebs_cmd); 430 tpebs_cmd = NULL; 431 } 432 } 433