1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2021 Red Hat Inc, Daniel Bristot de Oliveira <bristot@kernel.org> 4 */ 5 6 #define _GNU_SOURCE 7 #ifdef HAVE_LIBCPUPOWER_SUPPORT 8 #include <cpuidle.h> 9 #endif /* HAVE_LIBCPUPOWER_SUPPORT */ 10 #include <dirent.h> 11 #include <stdarg.h> 12 #include <stdlib.h> 13 #include <string.h> 14 #include <unistd.h> 15 #include <ctype.h> 16 #include <errno.h> 17 #include <fcntl.h> 18 #include <sched.h> 19 #include <stdio.h> 20 #include <limits.h> 21 22 #include "utils.h" 23 24 #define MAX_MSG_LENGTH 1024 25 int config_debug; 26 27 /* 28 * err_msg - print an error message to the stderr 29 */ 30 void err_msg(const char *fmt, ...) 31 { 32 char message[MAX_MSG_LENGTH]; 33 va_list ap; 34 35 va_start(ap, fmt); 36 vsnprintf(message, sizeof(message), fmt, ap); 37 va_end(ap); 38 39 fprintf(stderr, "%s", message); 40 } 41 42 /* 43 * debug_msg - print a debug message to stderr if debug is set 44 */ 45 void debug_msg(const char *fmt, ...) 46 { 47 char message[MAX_MSG_LENGTH]; 48 va_list ap; 49 50 if (!config_debug) 51 return; 52 53 va_start(ap, fmt); 54 vsnprintf(message, sizeof(message), fmt, ap); 55 va_end(ap); 56 57 fprintf(stderr, "%s", message); 58 } 59 60 /* 61 * fatal - print an error message and EOL to stderr and exit with ERROR 62 */ 63 void fatal(const char *fmt, ...) 64 { 65 va_list ap; 66 67 va_start(ap, fmt); 68 vfprintf(stderr, fmt, ap); 69 va_end(ap); 70 fprintf(stderr, "\n"); 71 72 exit(ERROR); 73 } 74 75 /* 76 * get_llong_from_str - get a long long int from a string 77 */ 78 long long get_llong_from_str(char *start) 79 { 80 long long value; 81 char *end; 82 83 errno = 0; 84 value = strtoll(start, &end, 10); 85 if (errno || start == end) 86 return -1; 87 88 return value; 89 } 90 91 /* 92 * get_duration - fill output with a human readable duration since start_time 93 */ 94 void get_duration(time_t start_time, char *output, int output_size) 95 { 96 time_t now = time(NULL); 97 struct tm *tm_info; 98 time_t duration; 99 100 duration = difftime(now, start_time); 101 tm_info = gmtime(&duration); 102 103 snprintf(output, output_size, "%3d %02d:%02d:%02d", 104 tm_info->tm_yday, 105 tm_info->tm_hour, 106 tm_info->tm_min, 107 tm_info->tm_sec); 108 } 109 110 /* 111 * parse_cpu_set - parse a cpu_list filling cpu_set_t argument 112 * 113 * Receives a cpu list, like 1-3,5 (cpus 1, 2, 3, 5), and then set 114 * filling cpu_set_t argument. 115 * 116 * Returns 1 on success, 0 otherwise. 117 */ 118 int parse_cpu_set(char *cpu_list, cpu_set_t *set) 119 { 120 const char *p; 121 int end_cpu; 122 int nr_cpus; 123 int cpu; 124 int i; 125 126 CPU_ZERO(set); 127 128 nr_cpus = sysconf(_SC_NPROCESSORS_CONF); 129 130 for (p = cpu_list; *p; ) { 131 if (strtoi(p, &cpu)) 132 goto err; 133 if (cpu < 0 || cpu >= nr_cpus) 134 goto err; 135 136 while (isdigit(*p)) 137 p++; 138 if (*p == '-') { 139 p++; 140 if (strtoi(p, &end_cpu)) 141 goto err; 142 if (end_cpu < cpu || end_cpu >= nr_cpus) 143 goto err; 144 while (isdigit(*p)) 145 p++; 146 } else 147 end_cpu = cpu; 148 149 if (cpu == end_cpu) { 150 debug_msg("cpu_set: adding cpu %d\n", cpu); 151 CPU_SET(cpu, set); 152 } else { 153 for (i = cpu; i <= end_cpu; i++) { 154 debug_msg("cpu_set: adding cpu %d\n", i); 155 CPU_SET(i, set); 156 } 157 } 158 159 if (*p == ',') 160 p++; 161 } 162 163 return 0; 164 err: 165 debug_msg("Error parsing the cpu set %s\n", cpu_list); 166 return 1; 167 } 168 169 /* 170 * parse_duration - parse duration with s/m/h/d suffix converting it to seconds 171 */ 172 long parse_seconds_duration(char *val) 173 { 174 char *end; 175 long t; 176 177 t = strtol(val, &end, 10); 178 179 if (end) { 180 switch (*end) { 181 case 's': 182 case 'S': 183 break; 184 case 'm': 185 case 'M': 186 t *= 60; 187 break; 188 case 'h': 189 case 'H': 190 t *= 60 * 60; 191 break; 192 193 case 'd': 194 case 'D': 195 t *= 24 * 60 * 60; 196 break; 197 } 198 } 199 200 return t; 201 } 202 203 /* 204 * parse_ns_duration - parse duration with ns/us/ms/s converting it to nanoseconds 205 */ 206 long parse_ns_duration(char *val) 207 { 208 char *end; 209 long t; 210 211 t = strtol(val, &end, 10); 212 213 if (end) { 214 if (!strncmp(end, "ns", 2)) { 215 return t; 216 } else if (!strncmp(end, "us", 2)) { 217 t *= 1000; 218 return t; 219 } else if (!strncmp(end, "ms", 2)) { 220 t *= 1000 * 1000; 221 return t; 222 } else if (!strncmp(end, "s", 1)) { 223 t *= 1000 * 1000 * 1000; 224 return t; 225 } 226 return -1; 227 } 228 229 return t; 230 } 231 232 /* 233 * This is a set of helper functions to use SCHED_DEADLINE. 234 */ 235 #ifndef __NR_sched_setattr 236 # ifdef __x86_64__ 237 # define __NR_sched_setattr 314 238 # elif __i386__ 239 # define __NR_sched_setattr 351 240 # elif __arm__ 241 # define __NR_sched_setattr 380 242 # elif __aarch64__ || __riscv 243 # define __NR_sched_setattr 274 244 # elif __powerpc__ 245 # define __NR_sched_setattr 355 246 # elif __s390x__ 247 # define __NR_sched_setattr 345 248 # elif __loongarch__ 249 # define __NR_sched_setattr 274 250 # endif 251 #endif 252 253 #define SCHED_DEADLINE 6 254 255 static inline int syscall_sched_setattr(pid_t pid, const struct sched_attr *attr, 256 unsigned int flags) { 257 return syscall(__NR_sched_setattr, pid, attr, flags); 258 } 259 260 int __set_sched_attr(int pid, struct sched_attr *attr) 261 { 262 int flags = 0; 263 int retval; 264 265 retval = syscall_sched_setattr(pid, attr, flags); 266 if (retval < 0) { 267 err_msg("Failed to set sched attributes to the pid %d: %s\n", 268 pid, strerror(errno)); 269 return 1; 270 } 271 272 return 0; 273 } 274 275 /* 276 * procfs_is_workload_pid - check if a procfs entry contains a comm_prefix* comm 277 * 278 * Check if the procfs entry is a directory of a process, and then check if the 279 * process has a comm with the prefix set in char *comm_prefix. As the 280 * current users of this function only check for kernel threads, there is no 281 * need to check for the threads for the process. 282 * 283 * Return: True if the proc_entry contains a comm file with comm_prefix*. 284 * Otherwise returns false. 285 */ 286 static int procfs_is_workload_pid(const char *comm_prefix, struct dirent *proc_entry) 287 { 288 char buffer[MAX_PATH]; 289 int comm_fd, retval; 290 char *t_name; 291 292 if (proc_entry->d_type != DT_DIR) 293 return 0; 294 295 if (*proc_entry->d_name == '.') 296 return 0; 297 298 /* check if the string is a pid */ 299 for (t_name = proc_entry->d_name; t_name; t_name++) { 300 if (!isdigit(*t_name)) 301 break; 302 } 303 304 if (*t_name != '\0') 305 return 0; 306 307 snprintf(buffer, MAX_PATH, "/proc/%s/comm", proc_entry->d_name); 308 comm_fd = open(buffer, O_RDONLY); 309 if (comm_fd < 0) 310 return 0; 311 312 memset(buffer, 0, MAX_PATH); 313 retval = read(comm_fd, buffer, MAX_PATH); 314 315 close(comm_fd); 316 317 if (retval <= 0) 318 return 0; 319 320 retval = strncmp(comm_prefix, buffer, strlen(comm_prefix)); 321 if (retval) 322 return 0; 323 324 /* comm already have \n */ 325 debug_msg("Found workload pid:%s comm:%s", proc_entry->d_name, buffer); 326 327 return 1; 328 } 329 330 /* 331 * set_comm_sched_attr - set sched params to threads starting with char *comm_prefix 332 * 333 * This function uses procfs to list the currently running threads and then set the 334 * sched_attr *attr to the threads that start with char *comm_prefix. It is 335 * mainly used to set the priority to the kernel threads created by the 336 * tracers. 337 */ 338 int set_comm_sched_attr(const char *comm_prefix, struct sched_attr *attr) 339 { 340 struct dirent *proc_entry; 341 DIR *procfs; 342 int retval; 343 int pid; 344 345 if (strlen(comm_prefix) >= MAX_PATH) { 346 err_msg("Command prefix is too long: %d < strlen(%s)\n", 347 MAX_PATH, comm_prefix); 348 return 1; 349 } 350 351 procfs = opendir("/proc"); 352 if (!procfs) { 353 err_msg("Could not open procfs\n"); 354 return 1; 355 } 356 357 while ((proc_entry = readdir(procfs))) { 358 359 retval = procfs_is_workload_pid(comm_prefix, proc_entry); 360 if (!retval) 361 continue; 362 363 if (strtoi(proc_entry->d_name, &pid)) { 364 err_msg("'%s' is not a valid pid", proc_entry->d_name); 365 goto out_err; 366 } 367 /* procfs_is_workload_pid confirmed it is a pid */ 368 retval = __set_sched_attr(pid, attr); 369 if (retval) { 370 err_msg("Error setting sched attributes for pid:%s\n", proc_entry->d_name); 371 goto out_err; 372 } 373 374 debug_msg("Set sched attributes for pid:%s\n", proc_entry->d_name); 375 } 376 return 0; 377 378 out_err: 379 closedir(procfs); 380 return 1; 381 } 382 383 #define INVALID_VAL (~0L) 384 static long get_long_ns_after_colon(char *start) 385 { 386 long val = INVALID_VAL; 387 388 /* find the ":" */ 389 start = strstr(start, ":"); 390 if (!start) 391 return -1; 392 393 /* skip ":" */ 394 start++; 395 val = parse_ns_duration(start); 396 397 return val; 398 } 399 400 static long get_long_after_colon(char *start) 401 { 402 long val = INVALID_VAL; 403 404 /* find the ":" */ 405 start = strstr(start, ":"); 406 if (!start) 407 return -1; 408 409 /* skip ":" */ 410 start++; 411 val = get_llong_from_str(start); 412 413 return val; 414 } 415 416 /* 417 * parse priority in the format: 418 * SCHED_OTHER: 419 * o:<prio> 420 * O:<prio> 421 * SCHED_RR: 422 * r:<prio> 423 * R:<prio> 424 * SCHED_FIFO: 425 * f:<prio> 426 * F:<prio> 427 * SCHED_DEADLINE: 428 * d:runtime:period 429 * D:runtime:period 430 */ 431 int parse_prio(char *arg, struct sched_attr *sched_param) 432 { 433 long prio; 434 long runtime; 435 long period; 436 437 memset(sched_param, 0, sizeof(*sched_param)); 438 sched_param->size = sizeof(*sched_param); 439 440 switch (arg[0]) { 441 case 'd': 442 case 'D': 443 /* d:runtime:period */ 444 if (strlen(arg) < 4) 445 return -1; 446 447 runtime = get_long_ns_after_colon(arg); 448 if (runtime == INVALID_VAL) 449 return -1; 450 451 period = get_long_ns_after_colon(&arg[2]); 452 if (period == INVALID_VAL) 453 return -1; 454 455 if (runtime > period) 456 return -1; 457 458 sched_param->sched_policy = SCHED_DEADLINE; 459 sched_param->sched_runtime = runtime; 460 sched_param->sched_deadline = period; 461 sched_param->sched_period = period; 462 break; 463 case 'f': 464 case 'F': 465 /* f:prio */ 466 prio = get_long_after_colon(arg); 467 if (prio == INVALID_VAL) 468 return -1; 469 470 if (prio < sched_get_priority_min(SCHED_FIFO)) 471 return -1; 472 if (prio > sched_get_priority_max(SCHED_FIFO)) 473 return -1; 474 475 sched_param->sched_policy = SCHED_FIFO; 476 sched_param->sched_priority = prio; 477 break; 478 case 'r': 479 case 'R': 480 /* r:prio */ 481 prio = get_long_after_colon(arg); 482 if (prio == INVALID_VAL) 483 return -1; 484 485 if (prio < sched_get_priority_min(SCHED_RR)) 486 return -1; 487 if (prio > sched_get_priority_max(SCHED_RR)) 488 return -1; 489 490 sched_param->sched_policy = SCHED_RR; 491 sched_param->sched_priority = prio; 492 break; 493 case 'o': 494 case 'O': 495 /* o:prio */ 496 prio = get_long_after_colon(arg); 497 if (prio == INVALID_VAL) 498 return -1; 499 500 if (prio < MIN_NICE) 501 return -1; 502 if (prio > MAX_NICE) 503 return -1; 504 505 sched_param->sched_policy = SCHED_OTHER; 506 sched_param->sched_nice = prio; 507 break; 508 default: 509 return -1; 510 } 511 return 0; 512 } 513 514 /* 515 * set_cpu_dma_latency - set the /dev/cpu_dma_latecy 516 * 517 * This is used to reduce the exit from idle latency. The value 518 * will be reset once the file descriptor of /dev/cpu_dma_latecy 519 * is closed. 520 * 521 * Return: the /dev/cpu_dma_latecy file descriptor 522 */ 523 int set_cpu_dma_latency(int32_t latency) 524 { 525 int retval; 526 int fd; 527 528 fd = open("/dev/cpu_dma_latency", O_RDWR); 529 if (fd < 0) { 530 err_msg("Error opening /dev/cpu_dma_latency\n"); 531 return -1; 532 } 533 534 retval = write(fd, &latency, 4); 535 if (retval < 1) { 536 err_msg("Error setting /dev/cpu_dma_latency\n"); 537 close(fd); 538 return -1; 539 } 540 541 debug_msg("Set /dev/cpu_dma_latency to %d\n", latency); 542 543 return fd; 544 } 545 546 #ifdef HAVE_LIBCPUPOWER_SUPPORT 547 static unsigned int **saved_cpu_idle_disable_state; 548 static size_t saved_cpu_idle_disable_state_alloc_ctr; 549 550 /* 551 * save_cpu_idle_state_disable - save disable for all idle states of a cpu 552 * 553 * Saves the current disable of all idle states of a cpu, to be subsequently 554 * restored via restore_cpu_idle_disable_state. 555 * 556 * Return: idle state count on success, negative on error 557 */ 558 int save_cpu_idle_disable_state(unsigned int cpu) 559 { 560 unsigned int nr_states; 561 unsigned int state; 562 int disabled; 563 int nr_cpus; 564 565 nr_states = cpuidle_state_count(cpu); 566 567 if (nr_states == 0) 568 return 0; 569 570 if (saved_cpu_idle_disable_state == NULL) { 571 nr_cpus = sysconf(_SC_NPROCESSORS_CONF); 572 saved_cpu_idle_disable_state = calloc(nr_cpus, sizeof(unsigned int *)); 573 if (!saved_cpu_idle_disable_state) 574 return -1; 575 } 576 577 saved_cpu_idle_disable_state[cpu] = calloc(nr_states, sizeof(unsigned int)); 578 if (!saved_cpu_idle_disable_state[cpu]) 579 return -1; 580 saved_cpu_idle_disable_state_alloc_ctr++; 581 582 for (state = 0; state < nr_states; state++) { 583 disabled = cpuidle_is_state_disabled(cpu, state); 584 if (disabled < 0) 585 return disabled; 586 saved_cpu_idle_disable_state[cpu][state] = disabled; 587 } 588 589 return nr_states; 590 } 591 592 /* 593 * restore_cpu_idle_disable_state - restore disable for all idle states of a cpu 594 * 595 * Restores the current disable state of all idle states of a cpu that was 596 * previously saved by save_cpu_idle_disable_state. 597 * 598 * Return: idle state count on success, negative on error 599 */ 600 int restore_cpu_idle_disable_state(unsigned int cpu) 601 { 602 unsigned int nr_states; 603 unsigned int state; 604 int disabled; 605 int result; 606 607 nr_states = cpuidle_state_count(cpu); 608 609 if (nr_states == 0) 610 return 0; 611 612 if (!saved_cpu_idle_disable_state) 613 return -1; 614 615 for (state = 0; state < nr_states; state++) { 616 if (!saved_cpu_idle_disable_state[cpu]) 617 return -1; 618 disabled = saved_cpu_idle_disable_state[cpu][state]; 619 result = cpuidle_state_disable(cpu, state, disabled); 620 if (result < 0) 621 return result; 622 } 623 624 free(saved_cpu_idle_disable_state[cpu]); 625 saved_cpu_idle_disable_state[cpu] = NULL; 626 saved_cpu_idle_disable_state_alloc_ctr--; 627 if (saved_cpu_idle_disable_state_alloc_ctr == 0) { 628 free(saved_cpu_idle_disable_state); 629 saved_cpu_idle_disable_state = NULL; 630 } 631 632 return nr_states; 633 } 634 635 /* 636 * free_cpu_idle_disable_states - free saved idle state disable for all cpus 637 * 638 * Frees the memory used for storing cpu idle state disable for all cpus 639 * and states. 640 * 641 * Normally, the memory is freed automatically in 642 * restore_cpu_idle_disable_state; this is mostly for cleaning up after an 643 * error. 644 */ 645 void free_cpu_idle_disable_states(void) 646 { 647 int cpu; 648 int nr_cpus; 649 650 if (!saved_cpu_idle_disable_state) 651 return; 652 653 nr_cpus = sysconf(_SC_NPROCESSORS_CONF); 654 655 for (cpu = 0; cpu < nr_cpus; cpu++) { 656 free(saved_cpu_idle_disable_state[cpu]); 657 saved_cpu_idle_disable_state[cpu] = NULL; 658 } 659 660 free(saved_cpu_idle_disable_state); 661 saved_cpu_idle_disable_state = NULL; 662 } 663 664 /* 665 * set_deepest_cpu_idle_state - limit idle state of cpu 666 * 667 * Disables all idle states deeper than the one given in 668 * deepest_state (assuming states with higher number are deeper). 669 * 670 * This is used to reduce the exit from idle latency. Unlike 671 * set_cpu_dma_latency, it can disable idle states per cpu. 672 * 673 * Return: idle state count on success, negative on error 674 */ 675 int set_deepest_cpu_idle_state(unsigned int cpu, unsigned int deepest_state) 676 { 677 unsigned int nr_states; 678 unsigned int state; 679 int result; 680 681 nr_states = cpuidle_state_count(cpu); 682 683 for (state = deepest_state + 1; state < nr_states; state++) { 684 result = cpuidle_state_disable(cpu, state, 1); 685 if (result < 0) 686 return result; 687 } 688 689 return nr_states; 690 } 691 #endif /* HAVE_LIBCPUPOWER_SUPPORT */ 692 693 #define _STR(x) #x 694 #define STR(x) _STR(x) 695 696 /* 697 * find_mount - find a the mount point of a given fs 698 * 699 * Returns 0 if mount is not found, otherwise return 1 and fill mp 700 * with the mount point. 701 */ 702 static const int find_mount(const char *fs, char *mp, int sizeof_mp) 703 { 704 char mount_point[MAX_PATH+1]; 705 char type[100]; 706 int found = 0; 707 FILE *fp; 708 709 fp = fopen("/proc/mounts", "r"); 710 if (!fp) 711 return 0; 712 713 while (fscanf(fp, "%*s %" STR(MAX_PATH) "s %99s %*s %*d %*d\n", mount_point, type) == 2) { 714 if (strcmp(type, fs) == 0) { 715 found = 1; 716 break; 717 } 718 } 719 fclose(fp); 720 721 if (!found) 722 return 0; 723 724 memset(mp, 0, sizeof_mp); 725 strncpy(mp, mount_point, sizeof_mp - 1); 726 727 debug_msg("Fs %s found at %s\n", fs, mp); 728 return 1; 729 } 730 731 /* 732 * get_self_cgroup - get the current thread cgroup path 733 * 734 * Parse /proc/$$/cgroup file to get the thread's cgroup. As an example of line to parse: 735 * 736 * 0::/user.slice/user-0.slice/session-3.scope'\n' 737 * 738 * This function is interested in the content after the second : and before the '\n'. 739 * 740 * Returns 1 if a string was found, 0 otherwise. 741 */ 742 static int get_self_cgroup(char *self_cg, int sizeof_self_cg) 743 { 744 char path[MAX_PATH], *start; 745 int fd, retval; 746 747 snprintf(path, MAX_PATH, "/proc/%d/cgroup", getpid()); 748 749 fd = open(path, O_RDONLY); 750 if (fd < 0) 751 return 0; 752 753 retval = read(fd, path, MAX_PATH); 754 755 close(fd); 756 757 if (retval <= 0) 758 return 0; 759 760 start = path; 761 762 start = strstr(start, ":"); 763 if (!start) 764 return 0; 765 766 /* skip ":" */ 767 start++; 768 769 start = strstr(start, ":"); 770 if (!start) 771 return 0; 772 773 /* skip ":" */ 774 start++; 775 776 if (strlen(start) >= sizeof_self_cg) 777 return 0; 778 779 snprintf(self_cg, sizeof_self_cg, "%s", start); 780 781 /* Swap '\n' with '\0' */ 782 start = strstr(self_cg, "\n"); 783 784 /* there must be '\n' */ 785 if (!start) 786 return 0; 787 788 /* ok, it found a string after the second : and before the \n */ 789 *start = '\0'; 790 791 return 1; 792 } 793 794 /* 795 * open_cgroup_procs - Open the cgroup.procs file for the given cgroup 796 * 797 * If cgroup argument is not NULL, the cgroup.procs file for that cgroup 798 * will be opened. Otherwise, the cgroup of the calling, i.e., rtla, thread 799 * will be used. 800 * 801 * Supports cgroup v2. 802 * 803 * Returns the file descriptor on success, -1 otherwise. 804 */ 805 static int open_cgroup_procs(const char *cgroup) 806 { 807 char cgroup_path[MAX_PATH - strlen("/cgroup.procs")]; 808 char cgroup_procs[MAX_PATH]; 809 int retval; 810 int cg_fd; 811 812 retval = find_mount("cgroup2", cgroup_path, sizeof(cgroup_path)); 813 if (!retval) { 814 err_msg("Did not find cgroupv2 mount point\n"); 815 return -1; 816 } 817 818 if (!cgroup) { 819 retval = get_self_cgroup(&cgroup_path[strlen(cgroup_path)], 820 sizeof(cgroup_path) - strlen(cgroup_path)); 821 if (!retval) { 822 err_msg("Did not find self cgroup\n"); 823 return -1; 824 } 825 } else { 826 snprintf(&cgroup_path[strlen(cgroup_path)], 827 sizeof(cgroup_path) - strlen(cgroup_path), "%s/", cgroup); 828 } 829 830 snprintf(cgroup_procs, MAX_PATH, "%s/cgroup.procs", cgroup_path); 831 832 debug_msg("Using cgroup path at: %s\n", cgroup_procs); 833 834 cg_fd = open(cgroup_procs, O_RDWR); 835 if (cg_fd < 0) 836 return -1; 837 838 return cg_fd; 839 } 840 841 /* 842 * set_pid_cgroup - Set cgroup to pid_t pid 843 * 844 * If cgroup argument is not NULL, the threads will move to the given cgroup. 845 * Otherwise, the cgroup of the calling, i.e., rtla, thread will be used. 846 * 847 * Supports cgroup v2. 848 * 849 * Returns 1 on success, 0 otherwise. 850 */ 851 int set_pid_cgroup(pid_t pid, const char *cgroup) 852 { 853 char pid_str[24]; 854 int retval; 855 int cg_fd; 856 857 cg_fd = open_cgroup_procs(cgroup); 858 if (cg_fd < 0) 859 return 0; 860 861 snprintf(pid_str, sizeof(pid_str), "%d\n", pid); 862 863 retval = write(cg_fd, pid_str, strlen(pid_str)); 864 if (retval < 0) 865 err_msg("Error setting cgroup attributes for pid:%s - %s\n", 866 pid_str, strerror(errno)); 867 else 868 debug_msg("Set cgroup attributes for pid:%s\n", pid_str); 869 870 close(cg_fd); 871 872 return (retval >= 0); 873 } 874 875 /** 876 * set_comm_cgroup - Set cgroup to threads starting with char *comm_prefix 877 * 878 * If cgroup argument is not NULL, the threads will move to the given cgroup. 879 * Otherwise, the cgroup of the calling, i.e., rtla, thread will be used. 880 * 881 * Supports cgroup v2. 882 * 883 * Returns 1 on success, 0 otherwise. 884 */ 885 int set_comm_cgroup(const char *comm_prefix, const char *cgroup) 886 { 887 struct dirent *proc_entry; 888 DIR *procfs; 889 int retval; 890 int cg_fd; 891 892 if (strlen(comm_prefix) >= MAX_PATH) { 893 err_msg("Command prefix is too long: %d < strlen(%s)\n", 894 MAX_PATH, comm_prefix); 895 return 0; 896 } 897 898 cg_fd = open_cgroup_procs(cgroup); 899 if (cg_fd < 0) 900 return 0; 901 902 procfs = opendir("/proc"); 903 if (!procfs) { 904 err_msg("Could not open procfs\n"); 905 goto out_cg; 906 } 907 908 while ((proc_entry = readdir(procfs))) { 909 910 retval = procfs_is_workload_pid(comm_prefix, proc_entry); 911 if (!retval) 912 continue; 913 914 retval = write(cg_fd, proc_entry->d_name, strlen(proc_entry->d_name)); 915 if (retval < 0) { 916 err_msg("Error setting cgroup attributes for pid:%s - %s\n", 917 proc_entry->d_name, strerror(errno)); 918 goto out_procfs; 919 } 920 921 debug_msg("Set cgroup attributes for pid:%s\n", proc_entry->d_name); 922 } 923 924 closedir(procfs); 925 close(cg_fd); 926 return 1; 927 928 out_procfs: 929 closedir(procfs); 930 out_cg: 931 close(cg_fd); 932 return 0; 933 } 934 935 /** 936 * auto_house_keeping - Automatically move rtla out of measurement threads 937 * 938 * Try to move rtla away from the tracer, if possible. 939 * 940 * Returns 1 on success, 0 otherwise. 941 */ 942 int auto_house_keeping(cpu_set_t *monitored_cpus) 943 { 944 cpu_set_t rtla_cpus, house_keeping_cpus; 945 int retval; 946 947 /* first get the CPUs in which rtla can actually run. */ 948 retval = sched_getaffinity(getpid(), sizeof(rtla_cpus), &rtla_cpus); 949 if (retval == -1) { 950 debug_msg("Could not get rtla affinity, rtla might run with the threads!\n"); 951 return 0; 952 } 953 954 /* then check if the existing setup is already good. */ 955 CPU_AND(&house_keeping_cpus, &rtla_cpus, monitored_cpus); 956 if (!CPU_COUNT(&house_keeping_cpus)) { 957 debug_msg("rtla and the monitored CPUs do not share CPUs."); 958 debug_msg("Skipping auto house-keeping\n"); 959 return 1; 960 } 961 962 /* remove the intersection */ 963 CPU_XOR(&house_keeping_cpus, &rtla_cpus, monitored_cpus); 964 965 /* get only those that rtla can run */ 966 CPU_AND(&house_keeping_cpus, &house_keeping_cpus, &rtla_cpus); 967 968 /* is there any cpu left? */ 969 if (!CPU_COUNT(&house_keeping_cpus)) { 970 debug_msg("Could not find any CPU for auto house-keeping\n"); 971 return 0; 972 } 973 974 retval = sched_setaffinity(getpid(), sizeof(house_keeping_cpus), &house_keeping_cpus); 975 if (retval == -1) { 976 debug_msg("Could not set affinity for auto house-keeping\n"); 977 return 0; 978 } 979 980 debug_msg("rtla automatically moved to an auto house-keeping cpu set\n"); 981 982 return 1; 983 } 984 985 /** 986 * parse_optional_arg - Parse optional argument value 987 * 988 * Parse optional argument value, which can be in the form of: 989 * -sarg, -s/--long=arg, -s/--long arg 990 * 991 * Returns arg value if found, NULL otherwise. 992 */ 993 char *parse_optional_arg(int argc, char **argv) 994 { 995 if (optarg) { 996 if (optarg[0] == '=') { 997 /* skip the = */ 998 return &optarg[1]; 999 } else { 1000 return optarg; 1001 } 1002 /* parse argument of form -s [arg] and --long [arg]*/ 1003 } else if (optind < argc && argv[optind][0] != '-') { 1004 /* consume optind */ 1005 return argv[optind++]; 1006 } else { 1007 return NULL; 1008 } 1009 } 1010 1011 /* 1012 * strtoi - convert string to integer with error checking 1013 * 1014 * Returns 0 on success, -1 if conversion fails or result is out of int range. 1015 */ 1016 int strtoi(const char *s, int *res) 1017 { 1018 char *end_ptr; 1019 long lres; 1020 1021 if (!*s) 1022 return -1; 1023 1024 errno = 0; 1025 lres = strtol(s, &end_ptr, 0); 1026 if (errno || *end_ptr || lres > INT_MAX || lres < INT_MIN) 1027 return -1; 1028 1029 *res = (int) lres; 1030 return 0; 1031 } 1032