tools/testing/selftests/resctrl/resctrl_val.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Memory bandwidth monitoring and allocation library
   4  *
   5  * Copyright (C) 2018 Intel Corporation
   6  *
   7  * Authors:
   8  *    Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>,
   9  *    Fenghua Yu <fenghua.yu@intel.com>
  10  */
  11 #include "resctrl.h"
  12
  13 #define UNCORE_IMC              "uncore_imc"
  14 #define READ_FILE_NAME          "events/cas_count_read"
  15 #define WRITE_FILE_NAME         "events/cas_count_write"
  16 #define DYN_PMU_PATH            "/sys/bus/event_source/devices"
  17 #define SCALE                   0.00006103515625
  18 #define MAX_IMCS                20
  19 #define MAX_TOKENS              5
  20 #define READ                    0
  21 #define WRITE                   1
  22 #define CON_MON_MBM_LOCAL_BYTES_PATH                            \
  23         "%s/%s/mon_groups/%s/mon_data/mon_L3_%02d/mbm_local_bytes"
  24
  25 #define CON_MBM_LOCAL_BYTES_PATH                \
  26         "%s/%s/mon_data/mon_L3_%02d/mbm_local_bytes"
  27
  28 #define MON_MBM_LOCAL_BYTES_PATH                \
  29         "%s/mon_groups/%s/mon_data/mon_L3_%02d/mbm_local_bytes"
  30
  31 #define MBM_LOCAL_BYTES_PATH                    \
  32         "%s/mon_data/mon_L3_%02d/mbm_local_bytes"
  33
  34 #define CON_MON_LCC_OCCUP_PATH          \
  35         "%s/%s/mon_groups/%s/mon_data/mon_L3_%02d/llc_occupancy"
  36
  37 #define CON_LCC_OCCUP_PATH              \
  38         "%s/%s/mon_data/mon_L3_%02d/llc_occupancy"
  39
  40 #define MON_LCC_OCCUP_PATH              \
  41         "%s/mon_groups/%s/mon_data/mon_L3_%02d/llc_occupancy"
  42
  43 #define LCC_OCCUP_PATH                  \
  44         "%s/mon_data/mon_L3_%02d/llc_occupancy"
  45
  46 struct membw_read_format {
  47         __u64 value;         /* The value of the event */
  48         __u64 time_enabled;  /* if PERF_FORMAT_TOTAL_TIME_ENABLED */
  49         __u64 time_running;  /* if PERF_FORMAT_TOTAL_TIME_RUNNING */
  50         __u64 id;            /* if PERF_FORMAT_ID */
  51 };
  52
  53 struct imc_counter_config {
  54         __u32 type;
  55         __u64 event;
  56         __u64 umask;
  57         struct perf_event_attr pe;
  58         struct membw_read_format return_value;
  59         int fd;
  60 };
  61
  62 static char mbm_total_path[1024];
  63 static int imcs;
  64 static struct imc_counter_config imc_counters_config[MAX_IMCS][2];
  65
  66 void membw_initialize_perf_event_attr(int i, int j)
  67 {
  68         memset(&imc_counters_config[i][j].pe, 0,
  69                sizeof(struct perf_event_attr));
  70         imc_counters_config[i][j].pe.type = imc_counters_config[i][j].type;
  71         imc_counters_config[i][j].pe.size = sizeof(struct perf_event_attr);
  72         imc_counters_config[i][j].pe.disabled = 1;
  73         imc_counters_config[i][j].pe.inherit = 1;
  74         imc_counters_config[i][j].pe.exclude_guest = 0;
  75         imc_counters_config[i][j].pe.config =
  76                 imc_counters_config[i][j].umask << 8 |
  77                 imc_counters_config[i][j].event;
  78         imc_counters_config[i][j].pe.sample_type = PERF_SAMPLE_IDENTIFIER;
  79         imc_counters_config[i][j].pe.read_format =
  80                 PERF_FORMAT_TOTAL_TIME_ENABLED | PERF_FORMAT_TOTAL_TIME_RUNNING;
  81 }
  82
  83 void membw_ioctl_perf_event_ioc_reset_enable(int i, int j)
  84 {
  85         ioctl(imc_counters_config[i][j].fd, PERF_EVENT_IOC_RESET, 0);
  86         ioctl(imc_counters_config[i][j].fd, PERF_EVENT_IOC_ENABLE, 0);
  87 }
  88
  89 void membw_ioctl_perf_event_ioc_disable(int i, int j)
  90 {
  91         ioctl(imc_counters_config[i][j].fd, PERF_EVENT_IOC_DISABLE, 0);
  92 }
  93
  94 /*
  95  * get_event_and_umask: Parse config into event and umask
  96  * @cas_count_cfg:      Config
  97  * @count:              iMC number
  98  * @op:                 Operation (read/write)
  99  */
 100 void get_event_and_umask(char *cas_count_cfg, int count, bool op)
 101 {
 102         char *token[MAX_TOKENS];
 103         int i = 0;
 104
 105         strcat(cas_count_cfg, ",");
 106         token[0] = strtok(cas_count_cfg, "=,");
 107
 108         for (i = 1; i < MAX_TOKENS; i++)
 109                 token[i] = strtok(NULL, "=,");
 110
 111         for (i = 0; i < MAX_TOKENS; i++) {
 112                 if (!token[i])
 113                         break;
 114                 if (strcmp(token[i], "event") == 0) {
 115                         if (op == READ)
 116                                 imc_counters_config[count][READ].event =
 117                                 strtol(token[i + 1], NULL, 16);
 118                         else
 119                                 imc_counters_config[count][WRITE].event =
 120                                 strtol(token[i + 1], NULL, 16);
 121                 }
 122                 if (strcmp(token[i], "umask") == 0) {
 123                         if (op == READ)
 124                                 imc_counters_config[count][READ].umask =
 125                                 strtol(token[i + 1], NULL, 16);
 126                         else
 127                                 imc_counters_config[count][WRITE].umask =
 128                                 strtol(token[i + 1], NULL, 16);
 129                 }
 130         }
 131 }
 132
 133 static int open_perf_event(int i, int cpu_no, int j)
 134 {
 135         imc_counters_config[i][j].fd =
 136                 perf_event_open(&imc_counters_config[i][j].pe, -1, cpu_no, -1,
 137                                 PERF_FLAG_FD_CLOEXEC);
 138
 139         if (imc_counters_config[i][j].fd == -1) {
 140                 fprintf(stderr, "Error opening leader %llx\n",
 141                         imc_counters_config[i][j].pe.config);
 142
 143                 return -1;
 144         }
 145
 146         return 0;
 147 }
 148
 149 /* Get type and config (read and write) of an iMC counter */
 150 static int read_from_imc_dir(char *imc_dir, int count)
 151 {
 152         char cas_count_cfg[1024], imc_counter_cfg[1024], imc_counter_type[1024];
 153         FILE *fp;
 154
 155         /* Get type of iMC counter */
 156         sprintf(imc_counter_type, "%s%s", imc_dir, "type");
 157         fp = fopen(imc_counter_type, "r");
 158         if (!fp) {
 159                 perror("Failed to open imc counter type file");
 160
 161                 return -1;
 162         }
 163         if (fscanf(fp, "%u", &imc_counters_config[count][READ].type) <= 0) {
 164                 perror("Could not get imc type");
 165                 fclose(fp);
 166
 167                 return -1;
 168         }
 169         fclose(fp);
 170
 171         imc_counters_config[count][WRITE].type =
 172                                 imc_counters_config[count][READ].type;
 173
 174         /* Get read config */
 175         sprintf(imc_counter_cfg, "%s%s", imc_dir, READ_FILE_NAME);
 176         fp = fopen(imc_counter_cfg, "r");
 177         if (!fp) {
 178                 perror("Failed to open imc config file");
 179
 180                 return -1;
 181         }
 182         if (fscanf(fp, "%s", cas_count_cfg) <= 0) {
 183                 perror("Could not get imc cas count read");
 184                 fclose(fp);
 185
 186                 return -1;
 187         }
 188         fclose(fp);
 189
 190         get_event_and_umask(cas_count_cfg, count, READ);
 191
 192         /* Get write config */
 193         sprintf(imc_counter_cfg, "%s%s", imc_dir, WRITE_FILE_NAME);
 194         fp = fopen(imc_counter_cfg, "r");
 195         if (!fp) {
 196                 perror("Failed to open imc config file");
 197
 198                 return -1;
 199         }
 200         if  (fscanf(fp, "%s", cas_count_cfg) <= 0) {
 201                 perror("Could not get imc cas count write");
 202                 fclose(fp);
 203
 204                 return -1;
 205         }
 206         fclose(fp);
 207
 208         get_event_and_umask(cas_count_cfg, count, WRITE);
 209
 210         return 0;
 211 }
 212
 213 /*
 214  * A system can have 'n' number of iMC (Integrated Memory Controller)
 215  * counters, get that 'n'. For each iMC counter get it's type and config.
 216  * Also, each counter has two configs, one for read and the other for write.
 217  * A config again has two parts, event and umask.
 218  * Enumerate all these details into an array of structures.
 219  *
 220  * Return: >= 0 on success. < 0 on failure.
 221  */
 222 static int num_of_imcs(void)
 223 {
 224         char imc_dir[512], *temp;
 225         unsigned int count = 0;
 226         struct dirent *ep;
 227         int ret;
 228         DIR *dp;
 229
 230         dp = opendir(DYN_PMU_PATH);
 231         if (dp) {
 232                 while ((ep = readdir(dp))) {
 233                         temp = strstr(ep->d_name, UNCORE_IMC);
 234                         if (!temp)
 235                                 continue;
 236
 237                         /*
 238                          * imc counters are named as "uncore_imc_<n>", hence
 239                          * increment the pointer to point to <n>. Note that
 240                          * sizeof(UNCORE_IMC) would count for null character as
 241                          * well and hence the last underscore character in
 242                          * uncore_imc'_' need not be counted.
 243                          */
 244                         temp = temp + sizeof(UNCORE_IMC);
 245
 246                         /*
 247                          * Some directories under "DYN_PMU_PATH" could have
 248                          * names like "uncore_imc_free_running", hence, check if
 249                          * first character is a numerical digit or not.
 250                          */
 251                         if (temp[0] >= '0' && temp[0] <= '9') {
 252                                 sprintf(imc_dir, "%s/%s/", DYN_PMU_PATH,
 253                                         ep->d_name);
 254                                 ret = read_from_imc_dir(imc_dir, count);
 255                                 if (ret) {
 256                                         closedir(dp);
 257
 258                                         return ret;
 259                                 }
 260                                 count++;
 261                         }
 262                 }
 263                 closedir(dp);
 264                 if (count == 0) {
 265                         perror("Unable find iMC counters!\n");
 266
 267                         return -1;
 268                 }
 269         } else {
 270                 perror("Unable to open PMU directory!\n");
 271
 272                 return -1;
 273         }
 274
 275         return count;
 276 }
 277
 278 static int initialize_mem_bw_imc(void)
 279 {
 280         int imc, j;
 281
 282         imcs = num_of_imcs();
 283         if (imcs <= 0)
 284                 return imcs;
 285
 286         /* Initialize perf_event_attr structures for all iMC's */
 287         for (imc = 0; imc < imcs; imc++) {
 288                 for (j = 0; j < 2; j++)
 289                         membw_initialize_perf_event_attr(imc, j);
 290         }
 291
 292         return 0;
 293 }
 294
 295 /*
 296  * get_mem_bw_imc:      Memory band width as reported by iMC counters
 297  * @cpu_no:             CPU number that the benchmark PID is binded to
 298  * @bw_report:          Bandwidth report type (reads, writes)
 299  *
 300  * Memory B/W utilized by a process on a socket can be calculated using
 301  * iMC counters. Perf events are used to read these counters.
 302  *
 303  * Return: = 0 on success. < 0 on failure.
 304  */
 305 static int get_mem_bw_imc(int cpu_no, char *bw_report, float *bw_imc)
 306 {
 307         float reads, writes, of_mul_read, of_mul_write;
 308         int imc, j, ret;
 309
 310         /* Start all iMC counters to log values (both read and write) */
 311         reads = 0, writes = 0, of_mul_read = 1, of_mul_write = 1;
 312         for (imc = 0; imc < imcs; imc++) {
 313                 for (j = 0; j < 2; j++) {
 314                         ret = open_perf_event(imc, cpu_no, j);
 315                         if (ret)
 316                                 return -1;
 317                 }
 318                 for (j = 0; j < 2; j++)
 319                         membw_ioctl_perf_event_ioc_reset_enable(imc, j);
 320         }
 321
 322         sleep(1);
 323
 324         /* Stop counters after a second to get results (both read and write) */
 325         for (imc = 0; imc < imcs; imc++) {
 326                 for (j = 0; j < 2; j++)
 327                         membw_ioctl_perf_event_ioc_disable(imc, j);
 328         }
 329
 330         /*
 331          * Get results which are stored in struct type imc_counter_config
 332          * Take over flow into consideration before calculating total b/w
 333          */
 334         for (imc = 0; imc < imcs; imc++) {
 335                 struct imc_counter_config *r =
 336                         &imc_counters_config[imc][READ];
 337                 struct imc_counter_config *w =
 338                         &imc_counters_config[imc][WRITE];
 339
 340                 if (read(r->fd, &r->return_value,
 341                          sizeof(struct membw_read_format)) == -1) {
 342                         perror("Couldn't get read b/w through iMC");
 343
 344                         return -1;
 345                 }
 346
 347                 if (read(w->fd, &w->return_value,
 348                          sizeof(struct membw_read_format)) == -1) {
 349                         perror("Couldn't get write bw through iMC");
 350
 351                         return -1;
 352                 }
 353
 354                 __u64 r_time_enabled = r->return_value.time_enabled;
 355                 __u64 r_time_running = r->return_value.time_running;
 356
 357                 if (r_time_enabled != r_time_running)
 358                         of_mul_read = (float)r_time_enabled /
 359                                         (float)r_time_running;
 360
 361                 __u64 w_time_enabled = w->return_value.time_enabled;
 362                 __u64 w_time_running = w->return_value.time_running;
 363
 364                 if (w_time_enabled != w_time_running)
 365                         of_mul_write = (float)w_time_enabled /
 366                                         (float)w_time_running;
 367                 reads += r->return_value.value * of_mul_read * SCALE;
 368                 writes += w->return_value.value * of_mul_write * SCALE;
 369         }
 370
 371         for (imc = 0; imc < imcs; imc++) {
 372                 close(imc_counters_config[imc][READ].fd);
 373                 close(imc_counters_config[imc][WRITE].fd);
 374         }
 375
 376         if (strcmp(bw_report, "reads") == 0) {
 377                 *bw_imc = reads;
 378                 return 0;
 379         }
 380
 381         if (strcmp(bw_report, "writes") == 0) {
 382                 *bw_imc = writes;
 383                 return 0;
 384         }
 385
 386         *bw_imc = reads + writes;
 387         return 0;
 388 }
 389
 390 void set_mbm_path(const char *ctrlgrp, const char *mongrp, int resource_id)
 391 {
 392         if (ctrlgrp && mongrp)
 393                 sprintf(mbm_total_path, CON_MON_MBM_LOCAL_BYTES_PATH,
 394                         RESCTRL_PATH, ctrlgrp, mongrp, resource_id);
 395         else if (!ctrlgrp && mongrp)
 396                 sprintf(mbm_total_path, MON_MBM_LOCAL_BYTES_PATH, RESCTRL_PATH,
 397                         mongrp, resource_id);
 398         else if (ctrlgrp && !mongrp)
 399                 sprintf(mbm_total_path, CON_MBM_LOCAL_BYTES_PATH, RESCTRL_PATH,
 400                         ctrlgrp, resource_id);
 401         else if (!ctrlgrp && !mongrp)
 402                 sprintf(mbm_total_path, MBM_LOCAL_BYTES_PATH, RESCTRL_PATH,
 403                         resource_id);
 404 }
 405
 406 /*
 407  * initialize_mem_bw_resctrl:   Appropriately populate "mbm_total_path"
 408  * @ctrlgrp:                    Name of the control monitor group (con_mon grp)
 409  * @mongrp:                     Name of the monitor group (mon grp)
 410  * @cpu_no:                     CPU number that the benchmark PID is binded to
 411  * @resctrl_val:                Resctrl feature (Eg: mbm, mba.. etc)
 412  */
 413 static void initialize_mem_bw_resctrl(const char *ctrlgrp, const char *mongrp,
 414                                       int cpu_no, char *resctrl_val)
 415 {
 416         int resource_id;
 417
 418         if (get_resource_id(cpu_no, &resource_id) < 0) {
 419                 perror("Could not get resource_id");
 420                 return;
 421         }
 422
 423         if (!strncmp(resctrl_val, MBM_STR, sizeof(MBM_STR)))
 424                 set_mbm_path(ctrlgrp, mongrp, resource_id);
 425
 426         if (!strncmp(resctrl_val, MBA_STR, sizeof(MBA_STR))) {
 427                 if (ctrlgrp)
 428                         sprintf(mbm_total_path, CON_MBM_LOCAL_BYTES_PATH,
 429                                 RESCTRL_PATH, ctrlgrp, resource_id);
 430                 else
 431                         sprintf(mbm_total_path, MBM_LOCAL_BYTES_PATH,
 432                                 RESCTRL_PATH, resource_id);
 433         }
 434 }
 435
 436 /*
 437  * Get MBM Local bytes as reported by resctrl FS
 438  * For MBM,
 439  * 1. If con_mon grp and mon grp are given, then read from con_mon grp's mon grp
 440  * 2. If only con_mon grp is given, then read from con_mon grp
 441  * 3. If both are not given, then read from root con_mon grp
 442  * For MBA,
 443  * 1. If con_mon grp is given, then read from it
 444  * 2. If con_mon grp is not given, then read from root con_mon grp
 445  */
 446 static int get_mem_bw_resctrl(unsigned long *mbm_total)
 447 {
 448         FILE *fp;
 449
 450         fp = fopen(mbm_total_path, "r");
 451         if (!fp) {
 452                 perror("Failed to open total bw file");
 453
 454                 return -1;
 455         }
 456         if (fscanf(fp, "%lu", mbm_total) <= 0) {
 457                 perror("Could not get mbm local bytes");
 458                 fclose(fp);
 459
 460                 return -1;
 461         }
 462         fclose(fp);
 463
 464         return 0;
 465 }
 466
 467 pid_t bm_pid, ppid;
 468
 469 void ctrlc_handler(int signum, siginfo_t *info, void *ptr)
 470 {
 471         kill(bm_pid, SIGKILL);
 472         umount_resctrlfs();
 473         tests_cleanup();
 474         ksft_print_msg("Ending\n\n");
 475
 476         exit(EXIT_SUCCESS);
 477 }
 478
 479 /*
 480  * Register CTRL-C handler for parent, as it has to kill
 481  * child process before exiting.
 482  */
 483 int signal_handler_register(void)
 484 {
 485         struct sigaction sigact;
 486         int ret = 0;
 487
 488         sigact.sa_sigaction = ctrlc_handler;
 489         sigemptyset(&sigact.sa_mask);
 490         sigact.sa_flags = SA_SIGINFO;
 491         if (sigaction(SIGINT, &sigact, NULL) ||
 492             sigaction(SIGTERM, &sigact, NULL) ||
 493             sigaction(SIGHUP, &sigact, NULL)) {
 494                 perror("# sigaction");
 495                 ret = -1;
 496         }
 497         return ret;
 498 }
 499
 500 /*
 501  * Reset signal handler to SIG_DFL.
 502  * Non-Value return because the caller should keep
 503  * the error code of other path even if sigaction fails.
 504  */
 505 void signal_handler_unregister(void)
 506 {
 507         struct sigaction sigact;
 508
 509         sigact.sa_handler = SIG_DFL;
 510         sigemptyset(&sigact.sa_mask);
 511         if (sigaction(SIGINT, &sigact, NULL) ||
 512             sigaction(SIGTERM, &sigact, NULL) ||
 513             sigaction(SIGHUP, &sigact, NULL)) {
 514                 perror("# sigaction");
 515         }
 516 }
 517
 518 /*
 519  * print_results_bw:    the memory bandwidth results are stored in a file
 520  * @filename:           file that stores the results
 521  * @bm_pid:             child pid that runs benchmark
 522  * @bw_imc:             perf imc counter value
 523  * @bw_resc:            memory bandwidth value
 524  *
 525  * Return:              0 on success. non-zero on failure.
 526  */
 527 static int print_results_bw(char *filename,  int bm_pid, float bw_imc,
 528                             unsigned long bw_resc)
 529 {
 530         unsigned long diff = fabs(bw_imc - bw_resc);
 531         FILE *fp;
 532
 533         if (strcmp(filename, "stdio") == 0 || strcmp(filename, "stderr") == 0) {
 534                 printf("Pid: %d \t Mem_BW_iMC: %f \t ", bm_pid, bw_imc);
 535                 printf("Mem_BW_resc: %lu \t Difference: %lu\n", bw_resc, diff);
 536         } else {
 537                 fp = fopen(filename, "a");
 538                 if (!fp) {
 539                         perror("Cannot open results file");
 540
 541                         return errno;
 542                 }
 543                 if (fprintf(fp, "Pid: %d \t Mem_BW_iMC: %f \t Mem_BW_resc: %lu \t Difference: %lu\n",
 544                             bm_pid, bw_imc, bw_resc, diff) <= 0) {
 545                         fclose(fp);
 546                         perror("Could not log results.");
 547
 548                         return errno;
 549                 }
 550                 fclose(fp);
 551         }
 552
 553         return 0;
 554 }
 555
 556 static void set_cmt_path(const char *ctrlgrp, const char *mongrp, char sock_num)
 557 {
 558         if (strlen(ctrlgrp) && strlen(mongrp))
 559                 sprintf(llc_occup_path, CON_MON_LCC_OCCUP_PATH, RESCTRL_PATH,
 560                         ctrlgrp, mongrp, sock_num);
 561         else if (!strlen(ctrlgrp) && strlen(mongrp))
 562                 sprintf(llc_occup_path, MON_LCC_OCCUP_PATH, RESCTRL_PATH,
 563                         mongrp, sock_num);
 564         else if (strlen(ctrlgrp) && !strlen(mongrp))
 565                 sprintf(llc_occup_path, CON_LCC_OCCUP_PATH, RESCTRL_PATH,
 566                         ctrlgrp, sock_num);
 567         else if (!strlen(ctrlgrp) && !strlen(mongrp))
 568                 sprintf(llc_occup_path, LCC_OCCUP_PATH, RESCTRL_PATH, sock_num);
 569 }
 570
 571 /*
 572  * initialize_llc_occu_resctrl: Appropriately populate "llc_occup_path"
 573  * @ctrlgrp:                    Name of the control monitor group (con_mon grp)
 574  * @mongrp:                     Name of the monitor group (mon grp)
 575  * @cpu_no:                     CPU number that the benchmark PID is binded to
 576  * @resctrl_val:                Resctrl feature (Eg: cat, cmt.. etc)
 577  */
 578 static void initialize_llc_occu_resctrl(const char *ctrlgrp, const char *mongrp,
 579                                         int cpu_no, char *resctrl_val)
 580 {
 581         int resource_id;
 582
 583         if (get_resource_id(cpu_no, &resource_id) < 0) {
 584                 perror("# Unable to resource_id");
 585                 return;
 586         }
 587
 588         if (!strncmp(resctrl_val, CMT_STR, sizeof(CMT_STR)))
 589                 set_cmt_path(ctrlgrp, mongrp, resource_id);
 590 }
 591
 592 static int
 593 measure_vals(struct resctrl_val_param *param, unsigned long *bw_resc_start)
 594 {
 595         unsigned long bw_resc, bw_resc_end;
 596         float bw_imc;
 597         int ret;
 598
 599         /*
 600          * Measure memory bandwidth from resctrl and from
 601          * another source which is perf imc value or could
 602          * be something else if perf imc event is not available.
 603          * Compare the two values to validate resctrl value.
 604          * It takes 1sec to measure the data.
 605          */
 606         ret = get_mem_bw_imc(param->cpu_no, param->bw_report, &bw_imc);
 607         if (ret < 0)
 608                 return ret;
 609
 610         ret = get_mem_bw_resctrl(&bw_resc_end);
 611         if (ret < 0)
 612                 return ret;
 613
 614         bw_resc = (bw_resc_end - *bw_resc_start) / MB;
 615         ret = print_results_bw(param->filename, bm_pid, bw_imc, bw_resc);
 616         if (ret)
 617                 return ret;
 618
 619         *bw_resc_start = bw_resc_end;
 620
 621         return 0;
 622 }
 623
 624 /*
 625  * resctrl_val: execute benchmark and measure memory bandwidth on
 626  *                      the benchmark
 627  * @benchmark_cmd:      benchmark command and its arguments
 628  * @param:              parameters passed to resctrl_val()
 629  *
 630  * Return:              0 on success. non-zero on failure.
 631  */
 632 int resctrl_val(char **benchmark_cmd, struct resctrl_val_param *param)
 633 {
 634         char *resctrl_val = param->resctrl_val;
 635         unsigned long bw_resc_start = 0;
 636         struct sigaction sigact;
 637         int ret = 0, pipefd[2];
 638         char pipe_message = 0;
 639         union sigval value;
 640
 641         if (strcmp(param->filename, "") == 0)
 642                 sprintf(param->filename, "stdio");
 643
 644         if (!strncmp(resctrl_val, MBA_STR, sizeof(MBA_STR)) ||
 645             !strncmp(resctrl_val, MBM_STR, sizeof(MBM_STR))) {
 646                 ret = validate_bw_report_request(param->bw_report);
 647                 if (ret)
 648                         return ret;
 649         }
 650
 651         /*
 652          * If benchmark wasn't successfully started by child, then child should
 653          * kill parent, so save parent's pid
 654          */
 655         ppid = getpid();
 656
 657         if (pipe(pipefd)) {
 658                 perror("# Unable to create pipe");
 659
 660                 return -1;
 661         }
 662
 663         /*
 664          * Fork to start benchmark, save child's pid so that it can be killed
 665          * when needed
 666          */
 667         fflush(stdout);
 668         bm_pid = fork();
 669         if (bm_pid == -1) {
 670                 perror("# Unable to fork");
 671
 672                 return -1;
 673         }
 674
 675         if (bm_pid == 0) {
 676                 /*
 677                  * Mask all signals except SIGUSR1, parent uses SIGUSR1 to
 678                  * start benchmark
 679                  */
 680                 sigfillset(&sigact.sa_mask);
 681                 sigdelset(&sigact.sa_mask, SIGUSR1);
 682
 683                 sigact.sa_sigaction = run_benchmark;
 684                 sigact.sa_flags = SA_SIGINFO;
 685
 686                 /* Register for "SIGUSR1" signal from parent */
 687                 if (sigaction(SIGUSR1, &sigact, NULL))
 688                         PARENT_EXIT("Can't register child for signal");
 689
 690                 /* Tell parent that child is ready */
 691                 close(pipefd[0]);
 692                 pipe_message = 1;
 693                 if (write(pipefd[1], &pipe_message, sizeof(pipe_message)) <
 694                     sizeof(pipe_message)) {
 695                         perror("# failed signaling parent process");
 696                         close(pipefd[1]);
 697                         return -1;
 698                 }
 699                 close(pipefd[1]);
 700
 701                 /* Suspend child until delivery of "SIGUSR1" from parent */
 702                 sigsuspend(&sigact.sa_mask);
 703
 704                 PARENT_EXIT("Child is done");
 705         }
 706
 707         ksft_print_msg("Benchmark PID: %d\n", bm_pid);
 708
 709         ret = signal_handler_register();
 710         if (ret)
 711                 goto out;
 712
 713         value.sival_ptr = benchmark_cmd;
 714
 715         /* Taskset benchmark to specified cpu */
 716         ret = taskset_benchmark(bm_pid, param->cpu_no);
 717         if (ret)
 718                 goto unregister;
 719
 720         /* Write benchmark to specified control&monitoring grp in resctrl FS */
 721         ret = write_bm_pid_to_resctrl(bm_pid, param->ctrlgrp, param->mongrp,
 722                                       resctrl_val);
 723         if (ret)
 724                 goto unregister;
 725
 726         if (!strncmp(resctrl_val, MBM_STR, sizeof(MBM_STR)) ||
 727             !strncmp(resctrl_val, MBA_STR, sizeof(MBA_STR))) {
 728                 ret = initialize_mem_bw_imc();
 729                 if (ret)
 730                         goto unregister;
 731
 732                 initialize_mem_bw_resctrl(param->ctrlgrp, param->mongrp,
 733                                           param->cpu_no, resctrl_val);
 734         } else if (!strncmp(resctrl_val, CMT_STR, sizeof(CMT_STR)))
 735                 initialize_llc_occu_resctrl(param->ctrlgrp, param->mongrp,
 736                                             param->cpu_no, resctrl_val);
 737
 738         /* Parent waits for child to be ready. */
 739         close(pipefd[1]);
 740         while (pipe_message != 1) {
 741                 if (read(pipefd[0], &pipe_message, sizeof(pipe_message)) <
 742                     sizeof(pipe_message)) {
 743                         perror("# failed reading message from child process");
 744                         close(pipefd[0]);
 745                         goto unregister;
 746                 }
 747         }
 748         close(pipefd[0]);
 749
 750         /* Signal child to start benchmark */
 751         if (sigqueue(bm_pid, SIGUSR1, value) == -1) {
 752                 perror("# sigqueue SIGUSR1 to child");
 753                 ret = errno;
 754                 goto unregister;
 755         }
 756
 757         /* Give benchmark enough time to fully run */
 758         sleep(1);
 759
 760         /* Test runs until the callback setup() tells the test to stop. */
 761         while (1) {
 762                 ret = param->setup(param);
 763                 if (ret == END_OF_TESTS) {
 764                         ret = 0;
 765                         break;
 766                 }
 767                 if (ret < 0)
 768                         break;
 769
 770                 if (!strncmp(resctrl_val, MBM_STR, sizeof(MBM_STR)) ||
 771                     !strncmp(resctrl_val, MBA_STR, sizeof(MBA_STR))) {
 772                         ret = measure_vals(param, &bw_resc_start);
 773                         if (ret)
 774                                 break;
 775                 } else if (!strncmp(resctrl_val, CMT_STR, sizeof(CMT_STR))) {
 776                         sleep(1);
 777                         ret = measure_cache_vals(param, bm_pid);
 778                         if (ret)
 779                                 break;
 780                 }
 781         }
 782
 783 unregister:
 784         signal_handler_unregister();
 785 out:
 786         kill(bm_pid, SIGKILL);
 787
 788         return ret;
 789 }