433 lines · c
1// SPDX-License-Identifier: GPL-2.0-only2/*3 * intel_tpebs.c: Intel TPEBS support4 */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 29bool tpebs_recording;30static pid_t tpebs_pid = -1;31static size_t tpebs_event_size;32static LIST_HEAD(tpebs_results);33static pthread_t tpebs_reader_thread;34static struct child_process *tpebs_cmd;35 36struct 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 50static 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 85static 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 95static 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);116out:117 free(record_argv);118 return ret;119}120 121static 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 retire135 * latency value will be used. Save the number of samples and the sum of136 * 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 150static 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 158static 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 */186static 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 sampled206 * to get the average retire_latency value.207 *208 * This function will be called from evlist level later when evlist__open() is209 * called consistently.210 */211int 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 and227 * prepare workload228 */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 hang307 * when perf record failed for any reason. The timeout value308 * 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 }329out:330 close(control_fd[0]);331 close(control_fd[1]);332 close(ack_fd[0]);333 close(ack_fd[1]);334 }335err:336 if (ret)337 tpebs_delete();338 return ret;339}340 341 342int 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 the355 * 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 is375 * not found from sampling data (record_tpebs not set or 0376 * 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 else388 val = 0;389 390 count->val = val;391 return 0;392}393 394static 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 and403 * process by calling tpebs_stop().404 *405 * This function is called from evlist_delete() and also from builtin-stat406 * stat_handle_error(). If tpebs_start() is called from places other then perf407 * stat, need to ensure tpebs_delete() is also called to safely free mem and408 * close the data read thread and the forked perf record process.409 *410 * This function is also called in evsel__close() to be symmetric with411 * tpebs_start() being called in evsel__open(). We will update this call site412 * when move tpebs_start() to evlist level.413 */414void 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