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
46struct 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
53struct 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
62static char mbm_total_path[1024];
63static int imcs;
64static struct imc_counter_config imc_counters_config[MAX_IMCS][2];
65
66void 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
83void 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
89void 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 */
100void 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(p: cas_count_cfg, q: ",");
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
133static int open_perf_event(int i, int cpu_no, int j)
134{
135 imc_counters_config[i][j].fd =
136 perf_event_open(hw_event: &imc_counters_config[i][j].pe, pid: -1, cpu: cpu_no, group_fd: -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 */
150static 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(buf: imc_counter_type, fmt: "%s%s", imc_dir, "type");
157 fp = fopen(imc_counter_type, "r");
158 if (!fp) {
159 ksft_perror(msg: "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 ksft_perror(msg: "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(buf: imc_counter_cfg, fmt: "%s%s", imc_dir, READ_FILE_NAME);
176 fp = fopen(imc_counter_cfg, "r");
177 if (!fp) {
178 ksft_perror(msg: "Failed to open iMC config file");
179
180 return -1;
181 }
182 if (fscanf(fp, "%s", cas_count_cfg) <= 0) {
183 ksft_perror(msg: "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(buf: imc_counter_cfg, fmt: "%s%s", imc_dir, WRITE_FILE_NAME);
194 fp = fopen(imc_counter_cfg, "r");
195 if (!fp) {
196 ksft_perror(msg: "Failed to open iMC config file");
197
198 return -1;
199 }
200 if (fscanf(fp, "%s", cas_count_cfg) <= 0) {
201 ksft_perror(msg: "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 */
222static 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(buf: imc_dir, fmt: "%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 ksft_print_msg(msg: "Unable to find iMC counters\n");
266
267 return -1;
268 }
269 } else {
270 ksft_perror(msg: "Unable to open PMU directory");
271
272 return -1;
273 }
274
275 return count;
276}
277
278static 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(i: 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 */
305static 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(i: 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(i: 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(i: 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 ksft_perror(msg: "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 ksft_perror(msg: "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
390void set_mbm_path(const char *ctrlgrp, const char *mongrp, int domain_id)
391{
392 if (ctrlgrp && mongrp)
393 sprintf(buf: mbm_total_path, CON_MON_MBM_LOCAL_BYTES_PATH,
394 RESCTRL_PATH, ctrlgrp, mongrp, domain_id);
395 else if (!ctrlgrp && mongrp)
396 sprintf(buf: mbm_total_path, MON_MBM_LOCAL_BYTES_PATH, RESCTRL_PATH,
397 mongrp, domain_id);
398 else if (ctrlgrp && !mongrp)
399 sprintf(buf: mbm_total_path, CON_MBM_LOCAL_BYTES_PATH, RESCTRL_PATH,
400 ctrlgrp, domain_id);
401 else if (!ctrlgrp && !mongrp)
402 sprintf(buf: mbm_total_path, MBM_LOCAL_BYTES_PATH, RESCTRL_PATH,
403 domain_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 */
413static void initialize_mem_bw_resctrl(const char *ctrlgrp, const char *mongrp,
414 int cpu_no, char *resctrl_val)
415{
416 int domain_id;
417
418 if (get_domain_id(resource: "MB", cpu_no, domain_id: &domain_id) < 0) {
419 ksft_print_msg(msg: "Could not get domain ID\n");
420 return;
421 }
422
423 if (!strncmp(resctrl_val, MBM_STR, sizeof(MBM_STR)))
424 set_mbm_path(ctrlgrp, mongrp, domain_id);
425
426 if (!strncmp(resctrl_val, MBA_STR, sizeof(MBA_STR))) {
427 if (ctrlgrp)
428 sprintf(buf: mbm_total_path, CON_MBM_LOCAL_BYTES_PATH,
429 RESCTRL_PATH, ctrlgrp, domain_id);
430 else
431 sprintf(buf: mbm_total_path, MBM_LOCAL_BYTES_PATH,
432 RESCTRL_PATH, domain_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 */
446static 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 ksft_perror(msg: "Failed to open total bw file");
453
454 return -1;
455 }
456 if (fscanf(fp, "%lu", mbm_total) <= 0) {
457 ksft_perror(msg: "Could not get mbm local bytes");
458 fclose(fp);
459
460 return -1;
461 }
462 fclose(fp);
463
464 return 0;
465}
466
467pid_t bm_pid, ppid;
468
469void ctrlc_handler(int signum, siginfo_t *info, void *ptr)
470{
471 /* Only kill child after bm_pid is set after fork() */
472 if (bm_pid)
473 kill(bm_pid, SIGKILL);
474 umount_resctrlfs();
475 tests_cleanup();
476 ksft_print_msg(msg: "Ending\n\n");
477
478 exit(EXIT_SUCCESS);
479}
480
481/*
482 * Register CTRL-C handler for parent, as it has to kill
483 * child process before exiting.
484 */
485int signal_handler_register(void)
486{
487 struct sigaction sigact = {};
488 int ret = 0;
489
490 bm_pid = 0;
491
492 sigact.sa_sigaction = ctrlc_handler;
493 sigemptyset(set: &sigact.sa_mask);
494 sigact.sa_flags = SA_SIGINFO;
495 if (sigaction(SIGINT, &sigact, NULL) ||
496 sigaction(SIGTERM, &sigact, NULL) ||
497 sigaction(SIGHUP, &sigact, NULL)) {
498 ksft_perror(msg: "sigaction");
499 ret = -1;
500 }
501 return ret;
502}
503
504/*
505 * Reset signal handler to SIG_DFL.
506 * Non-Value return because the caller should keep
507 * the error code of other path even if sigaction fails.
508 */
509void signal_handler_unregister(void)
510{
511 struct sigaction sigact = {};
512
513 sigact.sa_handler = SIG_DFL;
514 sigemptyset(set: &sigact.sa_mask);
515 if (sigaction(SIGINT, &sigact, NULL) ||
516 sigaction(SIGTERM, &sigact, NULL) ||
517 sigaction(SIGHUP, &sigact, NULL)) {
518 ksft_perror(msg: "sigaction");
519 }
520}
521
522/*
523 * print_results_bw: the memory bandwidth results are stored in a file
524 * @filename: file that stores the results
525 * @bm_pid: child pid that runs benchmark
526 * @bw_imc: perf imc counter value
527 * @bw_resc: memory bandwidth value
528 *
529 * Return: 0 on success, < 0 on error.
530 */
531static int print_results_bw(char *filename, int bm_pid, float bw_imc,
532 unsigned long bw_resc)
533{
534 unsigned long diff = fabs(bw_imc - bw_resc);
535 FILE *fp;
536
537 if (strcmp(filename, "stdio") == 0 || strcmp(filename, "stderr") == 0) {
538 printf("Pid: %d \t Mem_BW_iMC: %f \t ", bm_pid, bw_imc);
539 printf("Mem_BW_resc: %lu \t Difference: %lu\n", bw_resc, diff);
540 } else {
541 fp = fopen(filename, "a");
542 if (!fp) {
543 ksft_perror(msg: "Cannot open results file");
544
545 return -1;
546 }
547 if (fprintf(fp, "Pid: %d \t Mem_BW_iMC: %f \t Mem_BW_resc: %lu \t Difference: %lu\n",
548 bm_pid, bw_imc, bw_resc, diff) <= 0) {
549 ksft_print_msg(msg: "Could not log results\n");
550 fclose(fp);
551
552 return -1;
553 }
554 fclose(fp);
555 }
556
557 return 0;
558}
559
560static void set_cmt_path(const char *ctrlgrp, const char *mongrp, char sock_num)
561{
562 if (strlen(ctrlgrp) && strlen(mongrp))
563 sprintf(buf: llc_occup_path, CON_MON_LCC_OCCUP_PATH, RESCTRL_PATH,
564 ctrlgrp, mongrp, sock_num);
565 else if (!strlen(ctrlgrp) && strlen(mongrp))
566 sprintf(buf: llc_occup_path, MON_LCC_OCCUP_PATH, RESCTRL_PATH,
567 mongrp, sock_num);
568 else if (strlen(ctrlgrp) && !strlen(mongrp))
569 sprintf(buf: llc_occup_path, CON_LCC_OCCUP_PATH, RESCTRL_PATH,
570 ctrlgrp, sock_num);
571 else if (!strlen(ctrlgrp) && !strlen(mongrp))
572 sprintf(buf: llc_occup_path, LCC_OCCUP_PATH, RESCTRL_PATH, sock_num);
573}
574
575/*
576 * initialize_llc_occu_resctrl: Appropriately populate "llc_occup_path"
577 * @ctrlgrp: Name of the control monitor group (con_mon grp)
578 * @mongrp: Name of the monitor group (mon grp)
579 * @cpu_no: CPU number that the benchmark PID is binded to
580 * @resctrl_val: Resctrl feature (Eg: cat, cmt.. etc)
581 */
582static void initialize_llc_occu_resctrl(const char *ctrlgrp, const char *mongrp,
583 int cpu_no, char *resctrl_val)
584{
585 int domain_id;
586
587 if (get_domain_id(resource: "L3", cpu_no, domain_id: &domain_id) < 0) {
588 ksft_print_msg(msg: "Could not get domain ID\n");
589 return;
590 }
591
592 if (!strncmp(resctrl_val, CMT_STR, sizeof(CMT_STR)))
593 set_cmt_path(ctrlgrp, mongrp, sock_num: domain_id);
594}
595
596static int measure_vals(const struct user_params *uparams,
597 struct resctrl_val_param *param,
598 unsigned long *bw_resc_start)
599{
600 unsigned long bw_resc, bw_resc_end;
601 float bw_imc;
602 int ret;
603
604 /*
605 * Measure memory bandwidth from resctrl and from
606 * another source which is perf imc value or could
607 * be something else if perf imc event is not available.
608 * Compare the two values to validate resctrl value.
609 * It takes 1sec to measure the data.
610 */
611 ret = get_mem_bw_imc(cpu_no: uparams->cpu, bw_report: param->bw_report, bw_imc: &bw_imc);
612 if (ret < 0)
613 return ret;
614
615 ret = get_mem_bw_resctrl(mbm_total: &bw_resc_end);
616 if (ret < 0)
617 return ret;
618
619 bw_resc = (bw_resc_end - *bw_resc_start) / MB;
620 ret = print_results_bw(filename: param->filename, bm_pid, bw_imc, bw_resc);
621 if (ret)
622 return ret;
623
624 *bw_resc_start = bw_resc_end;
625
626 return 0;
627}
628
629/*
630 * run_benchmark - Run a specified benchmark or fill_buf (default benchmark)
631 * in specified signal. Direct benchmark stdio to /dev/null.
632 * @signum: signal number
633 * @info: signal info
634 * @ucontext: user context in signal handling
635 */
636static void run_benchmark(int signum, siginfo_t *info, void *ucontext)
637{
638 int operation, ret, memflush;
639 char **benchmark_cmd;
640 size_t span;
641 bool once;
642 FILE *fp;
643
644 benchmark_cmd = info->si_ptr;
645
646 /*
647 * Direct stdio of child to /dev/null, so that only parent writes to
648 * stdio (console)
649 */
650 fp = freopen("/dev/null", "w", stdout);
651 if (!fp) {
652 ksft_perror(msg: "Unable to direct benchmark status to /dev/null");
653 PARENT_EXIT();
654 }
655
656 if (strcmp(benchmark_cmd[0], "fill_buf") == 0) {
657 /* Execute default fill_buf benchmark */
658 span = strtoul(benchmark_cmd[1], NULL, 10);
659 memflush = atoi(benchmark_cmd[2]);
660 operation = atoi(benchmark_cmd[3]);
661 if (!strcmp(benchmark_cmd[4], "true")) {
662 once = true;
663 } else if (!strcmp(benchmark_cmd[4], "false")) {
664 once = false;
665 } else {
666 ksft_print_msg(msg: "Invalid once parameter\n");
667 PARENT_EXIT();
668 }
669
670 if (run_fill_buf(span, memflush, operation, once))
671 fprintf(stderr, "Error in running fill buffer\n");
672 } else {
673 /* Execute specified benchmark */
674 ret = execvp(benchmark_cmd[0], benchmark_cmd);
675 if (ret)
676 ksft_perror(msg: "execvp");
677 }
678
679 fclose(stdout);
680 ksft_print_msg(msg: "Unable to run specified benchmark\n");
681 PARENT_EXIT();
682}
683
684/*
685 * resctrl_val: execute benchmark and measure memory bandwidth on
686 * the benchmark
687 * @test: test information structure
688 * @uparams: user supplied parameters
689 * @benchmark_cmd: benchmark command and its arguments
690 * @param: parameters passed to resctrl_val()
691 *
692 * Return: 0 when the test was run, < 0 on error.
693 */
694int resctrl_val(const struct resctrl_test *test,
695 const struct user_params *uparams,
696 const char * const *benchmark_cmd,
697 struct resctrl_val_param *param)
698{
699 char *resctrl_val = param->resctrl_val;
700 unsigned long bw_resc_start = 0;
701 struct sigaction sigact;
702 int ret = 0, pipefd[2];
703 char pipe_message = 0;
704 union sigval value;
705
706 if (strcmp(param->filename, "") == 0)
707 sprintf(buf: param->filename, fmt: "stdio");
708
709 if (!strncmp(resctrl_val, MBA_STR, sizeof(MBA_STR)) ||
710 !strncmp(resctrl_val, MBM_STR, sizeof(MBM_STR))) {
711 ret = validate_bw_report_request(bw_report: param->bw_report);
712 if (ret)
713 return ret;
714 }
715
716 /*
717 * If benchmark wasn't successfully started by child, then child should
718 * kill parent, so save parent's pid
719 */
720 ppid = getpid();
721
722 if (pipe(pipefd)) {
723 ksft_perror(msg: "Unable to create pipe");
724
725 return -1;
726 }
727
728 /*
729 * Fork to start benchmark, save child's pid so that it can be killed
730 * when needed
731 */
732 fflush(stdout);
733 bm_pid = fork();
734 if (bm_pid == -1) {
735 ksft_perror(msg: "Unable to fork");
736
737 return -1;
738 }
739
740 if (bm_pid == 0) {
741 /*
742 * Mask all signals except SIGUSR1, parent uses SIGUSR1 to
743 * start benchmark
744 */
745 sigfillset(set: &sigact.sa_mask);
746 sigdelset(set: &sigact.sa_mask, SIGUSR1);
747
748 sigact.sa_sigaction = run_benchmark;
749 sigact.sa_flags = SA_SIGINFO;
750
751 /* Register for "SIGUSR1" signal from parent */
752 if (sigaction(SIGUSR1, &sigact, NULL)) {
753 ksft_perror(msg: "Can't register child for signal");
754 PARENT_EXIT();
755 }
756
757 /* Tell parent that child is ready */
758 close(pipefd[0]);
759 pipe_message = 1;
760 if (write(pipefd[1], &pipe_message, sizeof(pipe_message)) <
761 sizeof(pipe_message)) {
762 ksft_perror(msg: "Failed signaling parent process");
763 close(pipefd[1]);
764 return -1;
765 }
766 close(pipefd[1]);
767
768 /* Suspend child until delivery of "SIGUSR1" from parent */
769 sigsuspend(&sigact.sa_mask);
770
771 ksft_perror(msg: "Child is done");
772 PARENT_EXIT();
773 }
774
775 ksft_print_msg(msg: "Benchmark PID: %d\n", bm_pid);
776
777 /*
778 * The cast removes constness but nothing mutates benchmark_cmd within
779 * the context of this process. At the receiving process, it becomes
780 * argv, which is mutable, on exec() but that's after fork() so it
781 * doesn't matter for the process running the tests.
782 */
783 value.sival_ptr = (void *)benchmark_cmd;
784
785 /* Taskset benchmark to specified cpu */
786 ret = taskset_benchmark(bm_pid, uparams->cpu, NULL);
787 if (ret)
788 goto out;
789
790 /* Write benchmark to specified control&monitoring grp in resctrl FS */
791 ret = write_bm_pid_to_resctrl(bm_pid, ctrlgrp: param->ctrlgrp, mongrp: param->mongrp,
792 resctrl_val);
793 if (ret)
794 goto out;
795
796 if (!strncmp(resctrl_val, MBM_STR, sizeof(MBM_STR)) ||
797 !strncmp(resctrl_val, MBA_STR, sizeof(MBA_STR))) {
798 ret = initialize_mem_bw_imc();
799 if (ret)
800 goto out;
801
802 initialize_mem_bw_resctrl(ctrlgrp: param->ctrlgrp, mongrp: param->mongrp,
803 cpu_no: uparams->cpu, resctrl_val);
804 } else if (!strncmp(resctrl_val, CMT_STR, sizeof(CMT_STR)))
805 initialize_llc_occu_resctrl(ctrlgrp: param->ctrlgrp, mongrp: param->mongrp,
806 cpu_no: uparams->cpu, resctrl_val);
807
808 /* Parent waits for child to be ready. */
809 close(pipefd[1]);
810 while (pipe_message != 1) {
811 if (read(pipefd[0], &pipe_message, sizeof(pipe_message)) <
812 sizeof(pipe_message)) {
813 ksft_perror(msg: "Failed reading message from child process");
814 close(pipefd[0]);
815 goto out;
816 }
817 }
818 close(pipefd[0]);
819
820 /* Signal child to start benchmark */
821 if (sigqueue(bm_pid, SIGUSR1, value) == -1) {
822 ksft_perror(msg: "sigqueue SIGUSR1 to child");
823 ret = -1;
824 goto out;
825 }
826
827 /* Give benchmark enough time to fully run */
828 sleep(1);
829
830 /* Test runs until the callback setup() tells the test to stop. */
831 while (1) {
832 ret = param->setup(test, uparams, param);
833 if (ret == END_OF_TESTS) {
834 ret = 0;
835 break;
836 }
837 if (ret < 0)
838 break;
839
840 if (!strncmp(resctrl_val, MBM_STR, sizeof(MBM_STR)) ||
841 !strncmp(resctrl_val, MBA_STR, sizeof(MBA_STR))) {
842 ret = measure_vals(uparams, param, bw_resc_start: &bw_resc_start);
843 if (ret)
844 break;
845 } else if (!strncmp(resctrl_val, CMT_STR, sizeof(CMT_STR))) {
846 sleep(1);
847 ret = measure_llc_resctrl(filename: param->filename, bm_pid);
848 if (ret)
849 break;
850 }
851 }
852
853out:
854 kill(bm_pid, SIGKILL);
855
856 return ret;
857}
858

source code of linux/tools/testing/selftests/resctrl/resctrl_val.c