1 // SPDX-License-Identifier: GPL-2.0
3 * Basic resctrl file system operations
5 * Copyright (C) 2018 Intel Corporation
8 * Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>,
9 * Fenghua Yu <fenghua.yu@intel.com>
16 static int find_resctrl_mount(char *buffer)
19 char line[256], *fs, *mntpoint;
21 mounts = fopen("/proc/mounts", "r");
23 ksft_perror("/proc/mounts");
26 while (!feof(mounts)) {
27 if (!fgets(line, 256, mounts))
29 fs = strtok(line, " \t");
32 mntpoint = strtok(NULL, " \t");
35 fs = strtok(NULL, " \t");
38 if (strcmp(fs, "resctrl"))
43 strncpy(buffer, mntpoint, 256);
54 * mount_resctrlfs - Mount resctrl FS at /sys/fs/resctrl
56 * Mounts resctrl FS. Fails if resctrl FS is already mounted to avoid
57 * pre-existing settings interfering with the test results.
59 * Return: 0 on success, < 0 on error.
61 int mount_resctrlfs(void)
65 ret = find_resctrl_mount(NULL);
69 ksft_print_msg("Mounting resctrl to \"%s\"\n", RESCTRL_PATH);
70 ret = mount("resctrl", RESCTRL_PATH, "resctrl", 0, NULL);
77 int umount_resctrlfs(void)
82 ret = find_resctrl_mount(mountpoint);
88 if (umount(mountpoint)) {
89 ksft_perror("Unable to umount resctrl");
98 * get_cache_level - Convert cache level from string to integer
99 * @cache_type: Cache level as string
101 * Return: cache level as integer or -1 if @cache_type is invalid.
103 static int get_cache_level(const char *cache_type)
105 if (!strcmp(cache_type, "L3"))
107 if (!strcmp(cache_type, "L2"))
110 ksft_print_msg("Invalid cache level\n");
114 static int get_resource_cache_level(const char *resource)
116 /* "MB" use L3 (LLC) as resource */
117 if (!strcmp(resource, "MB"))
119 return get_cache_level(resource);
123 * get_domain_id - Get resctrl domain ID for a specified CPU
124 * @resource: resource name
125 * @cpu_no: CPU number
126 * @domain_id: domain ID (cache ID; for MB, L3 cache ID)
128 * Return: >= 0 on success, < 0 on failure.
130 int get_domain_id(const char *resource, int cpu_no, int *domain_id)
132 char phys_pkg_path[1024];
136 cache_num = get_resource_cache_level(resource);
140 sprintf(phys_pkg_path, "%s%d/cache/index%d/id", PHYS_ID_PATH, cpu_no, cache_num);
142 fp = fopen(phys_pkg_path, "r");
144 ksft_perror("Failed to open cache id file");
148 if (fscanf(fp, "%d", domain_id) <= 0) {
149 ksft_perror("Could not get domain ID");
160 * get_cache_size - Get cache size for a specified CPU
161 * @cpu_no: CPU number
162 * @cache_type: Cache level L2/L3
163 * @cache_size: pointer to cache_size
165 * Return: = 0 on success, < 0 on failure.
167 int get_cache_size(int cpu_no, const char *cache_type, unsigned long *cache_size)
169 char cache_path[1024], cache_str[64];
170 int length, i, cache_num;
173 cache_num = get_cache_level(cache_type);
177 sprintf(cache_path, "/sys/bus/cpu/devices/cpu%d/cache/index%d/size",
179 fp = fopen(cache_path, "r");
181 ksft_perror("Failed to open cache size");
185 if (fscanf(fp, "%s", cache_str) <= 0) {
186 ksft_perror("Could not get cache_size");
193 length = (int)strlen(cache_str);
197 for (i = 0; i < length; i++) {
198 if ((cache_str[i] >= '0') && (cache_str[i] <= '9'))
200 *cache_size = *cache_size * 10 + (cache_str[i] - '0');
202 else if (cache_str[i] == 'K')
204 *cache_size = *cache_size * 1024;
206 else if (cache_str[i] == 'M')
208 *cache_size = *cache_size * 1024 * 1024;
217 #define CORE_SIBLINGS_PATH "/sys/bus/cpu/devices/cpu"
220 * get_bit_mask - Get bit mask from given file
221 * @filename: File containing the mask
222 * @mask: The bit mask returned as unsigned long
224 * Return: = 0 on success, < 0 on failure.
226 static int get_bit_mask(const char *filename, unsigned long *mask)
230 if (!filename || !mask)
233 fp = fopen(filename, "r");
235 ksft_print_msg("Failed to open bit mask file '%s': %s\n",
236 filename, strerror(errno));
240 if (fscanf(fp, "%lx", mask) <= 0) {
241 ksft_print_msg("Could not read bit mask file '%s': %s\n",
242 filename, strerror(errno));
253 * resource_info_unsigned_get - Read an unsigned value from
254 * /sys/fs/resctrl/info/@resource/@filename
255 * @resource: Resource name that matches directory name in
256 * /sys/fs/resctrl/info
257 * @filename: File in /sys/fs/resctrl/info/@resource
258 * @val: Contains read value on success.
260 * Return: = 0 on success, < 0 on failure. On success the read
261 * value is saved into @val.
263 int resource_info_unsigned_get(const char *resource, const char *filename,
266 char file_path[PATH_MAX];
269 snprintf(file_path, sizeof(file_path), "%s/%s/%s", INFO_PATH, resource,
272 fp = fopen(file_path, "r");
274 ksft_print_msg("Error opening %s: %m\n", file_path);
278 if (fscanf(fp, "%u", val) <= 0) {
279 ksft_print_msg("Could not get contents of %s: %m\n", file_path);
289 * create_bit_mask- Create bit mask from start, len pair
290 * @start: LSB of the mask
291 * @len Number of bits in the mask
293 unsigned long create_bit_mask(unsigned int start, unsigned int len)
295 return ((1UL << len) - 1UL) << start;
299 * count_contiguous_bits - Returns the longest train of bits in a bit mask
301 * @start The location of the least-significant bit of the longest train
303 * Return: The length of the contiguous bits in the longest train of bits
305 unsigned int count_contiguous_bits(unsigned long val, unsigned int *start)
307 unsigned long last_val;
308 unsigned int count = 0;
318 *start = ffsl(last_val) - 1;
327 * get_full_cbm - Get full Cache Bit Mask (CBM)
328 * @cache_type: Cache type as "L2" or "L3"
329 * @mask: Full cache bit mask representing the maximal portion of cache
330 * available for allocation, returned as unsigned long.
332 * Return: = 0 on success, < 0 on failure.
334 int get_full_cbm(const char *cache_type, unsigned long *mask)
336 char cbm_path[PATH_MAX];
342 snprintf(cbm_path, sizeof(cbm_path), "%s/%s/cbm_mask",
343 INFO_PATH, cache_type);
345 ret = get_bit_mask(cbm_path, mask);
353 * get_shareable_mask - Get shareable mask from shareable_bits
354 * @cache_type: Cache type as "L2" or "L3"
355 * @shareable_mask: Shareable mask returned as unsigned long
357 * Return: = 0 on success, < 0 on failure.
359 static int get_shareable_mask(const char *cache_type, unsigned long *shareable_mask)
361 char mask_path[PATH_MAX];
366 snprintf(mask_path, sizeof(mask_path), "%s/%s/shareable_bits",
367 INFO_PATH, cache_type);
369 return get_bit_mask(mask_path, shareable_mask);
373 * get_mask_no_shareable - Get Cache Bit Mask (CBM) without shareable bits
374 * @cache_type: Cache type as "L2" or "L3"
375 * @mask: The largest exclusive portion of the cache out of the
376 * full CBM, returned as unsigned long
378 * Parts of a cache may be shared with other devices such as GPU. This function
379 * calculates the largest exclusive portion of the cache where no other devices
380 * besides CPU have access to the cache portion.
382 * Return: = 0 on success, < 0 on failure.
384 int get_mask_no_shareable(const char *cache_type, unsigned long *mask)
386 unsigned long full_mask, shareable_mask;
387 unsigned int start, len;
389 if (get_full_cbm(cache_type, &full_mask) < 0)
391 if (get_shareable_mask(cache_type, &shareable_mask) < 0)
394 len = count_contiguous_bits(full_mask & ~shareable_mask, &start);
398 *mask = create_bit_mask(start, len);
404 * taskset_benchmark - Taskset PID (i.e. benchmark) to a specified cpu
405 * @bm_pid: PID that should be binded
406 * @cpu_no: CPU number at which the PID would be binded
407 * @old_affinity: When not NULL, set to old CPU affinity
409 * Return: 0 on success, < 0 on error.
411 int taskset_benchmark(pid_t bm_pid, int cpu_no, cpu_set_t *old_affinity)
416 CPU_ZERO(old_affinity);
417 if (sched_getaffinity(bm_pid, sizeof(*old_affinity),
419 ksft_perror("Unable to read CPU affinity");
425 CPU_SET(cpu_no, &my_set);
427 if (sched_setaffinity(bm_pid, sizeof(cpu_set_t), &my_set)) {
428 ksft_perror("Unable to taskset benchmark");
437 * taskset_restore - Taskset PID to the earlier CPU affinity
438 * @bm_pid: PID that should be reset
439 * @old_affinity: The old CPU affinity to restore
441 * Return: 0 on success, < 0 on error.
443 int taskset_restore(pid_t bm_pid, cpu_set_t *old_affinity)
445 if (sched_setaffinity(bm_pid, sizeof(*old_affinity), old_affinity)) {
446 ksft_perror("Unable to restore CPU affinity");
454 * create_grp - Create a group only if one doesn't exist
455 * @grp_name: Name of the group
456 * @grp: Full path and name of the group
457 * @parent_grp: Full path and name of the parent group
459 * Return: 0 on success, < 0 on error.
461 static int create_grp(const char *grp_name, char *grp, const char *parent_grp)
468 * At this point, we are guaranteed to have resctrl FS mounted and if
469 * length of grp_name == 0, it means, user wants to use root con_mon
472 if (strlen(grp_name) == 0)
475 /* Check if requested grp exists or not */
476 dp = opendir(parent_grp);
478 while ((ep = readdir(dp)) != NULL) {
479 if (strcmp(ep->d_name, grp_name) == 0)
484 ksft_perror("Unable to open resctrl for group");
489 /* Requested grp doesn't exist, hence create it */
490 if (found_grp == 0) {
491 if (mkdir(grp, 0) == -1) {
492 ksft_perror("Unable to create group");
501 static int write_pid_to_tasks(char *tasks, pid_t pid)
505 fp = fopen(tasks, "w");
507 ksft_perror("Failed to open tasks file");
511 if (fprintf(fp, "%d\n", pid) < 0) {
512 ksft_print_msg("Failed to write pid to tasks file\n");
523 * write_bm_pid_to_resctrl - Write a PID (i.e. benchmark) to resctrl FS
524 * @bm_pid: PID that should be written
525 * @ctrlgrp: Name of the control monitor group (con_mon grp)
526 * @mongrp: Name of the monitor group (mon grp)
527 * @resctrl_val: Resctrl feature (Eg: mbm, mba.. etc)
529 * If a con_mon grp is requested, create it and write pid to it, otherwise
530 * write pid to root con_mon grp.
531 * If a mon grp is requested, create it and write pid to it, otherwise
532 * pid is not written, this means that pid is in con_mon grp and hence
533 * should consult con_mon grp's mon_data directory for results.
535 * Return: 0 on success, < 0 on error.
537 int write_bm_pid_to_resctrl(pid_t bm_pid, char *ctrlgrp, char *mongrp,
540 char controlgroup[128], monitorgroup[512], monitorgroup_p[256];
545 sprintf(controlgroup, "%s/%s", RESCTRL_PATH, ctrlgrp);
547 sprintf(controlgroup, "%s", RESCTRL_PATH);
549 /* Create control and monitoring group and write pid into it */
550 ret = create_grp(ctrlgrp, controlgroup, RESCTRL_PATH);
553 sprintf(tasks, "%s/tasks", controlgroup);
554 ret = write_pid_to_tasks(tasks, bm_pid);
558 /* Create mon grp and write pid into it for "mbm" and "cmt" test */
559 if (!strncmp(resctrl_val, CMT_STR, sizeof(CMT_STR)) ||
560 !strncmp(resctrl_val, MBM_STR, sizeof(MBM_STR))) {
561 if (strlen(mongrp)) {
562 sprintf(monitorgroup_p, "%s/mon_groups", controlgroup);
563 sprintf(monitorgroup, "%s/%s", monitorgroup_p, mongrp);
564 ret = create_grp(mongrp, monitorgroup, monitorgroup_p);
568 sprintf(tasks, "%s/mon_groups/%s/tasks",
569 controlgroup, mongrp);
570 ret = write_pid_to_tasks(tasks, bm_pid);
577 ksft_print_msg("Writing benchmark parameters to resctrl FS\n");
579 ksft_print_msg("Failed writing to resctrlfs\n");
585 * write_schemata - Update schemata of a con_mon grp
586 * @ctrlgrp: Name of the con_mon grp
587 * @schemata: Schemata that should be updated to
588 * @cpu_no: CPU number that the benchmark PID is binded to
589 * @resource: Resctrl resource (Eg: MB, L3, L2, etc.)
591 * Update schemata of a con_mon grp *only* if requested resctrl resource is
594 * Return: 0 on success, < 0 on error.
596 int write_schemata(char *ctrlgrp, char *schemata, int cpu_no, const char *resource)
598 char controlgroup[1024], reason[128], schema[1024] = {};
599 int domain_id, fd, schema_len, ret = 0;
602 ksft_print_msg("Skipping empty schemata update\n");
607 if (get_domain_id(resource, cpu_no, &domain_id) < 0) {
608 sprintf(reason, "Failed to get domain ID");
614 if (strlen(ctrlgrp) != 0)
615 sprintf(controlgroup, "%s/%s/schemata", RESCTRL_PATH, ctrlgrp);
617 sprintf(controlgroup, "%s/schemata", RESCTRL_PATH);
619 schema_len = snprintf(schema, sizeof(schema), "%s:%d=%s\n",
620 resource, domain_id, schemata);
621 if (schema_len < 0 || schema_len >= sizeof(schema)) {
622 snprintf(reason, sizeof(reason),
623 "snprintf() failed with return value : %d", schema_len);
628 fd = open(controlgroup, O_WRONLY);
630 snprintf(reason, sizeof(reason),
631 "open() failed : %s", strerror(errno));
634 goto err_schema_not_empty;
636 if (write(fd, schema, schema_len) < 0) {
637 snprintf(reason, sizeof(reason),
638 "write() failed : %s", strerror(errno));
642 goto err_schema_not_empty;
646 err_schema_not_empty:
647 schema[schema_len - 1] = 0;
649 ksft_print_msg("Write schema \"%s\" to resctrl FS%s%s\n",
650 schema, ret ? " # " : "",
656 bool check_resctrlfs_support(void)
658 FILE *inf = fopen("/proc/filesystems", "r");
666 res = fgrep(inf, "nodev\tresctrl\n");
675 ksft_print_msg("%s Check kernel supports resctrl filesystem\n",
676 ret ? "Pass:" : "Fail:");
681 dp = opendir(RESCTRL_PATH);
682 ksft_print_msg("%s Check resctrl mountpoint \"%s\" exists\n",
683 dp ? "Pass:" : "Fail:", RESCTRL_PATH);
687 ksft_print_msg("resctrl filesystem %s mounted\n",
688 find_resctrl_mount(NULL) ? "not" : "is");
693 char *fgrep(FILE *inf, const char *str)
696 int slen = strlen(str);
699 if (!fgets(line, 256, inf))
701 if (strncmp(line, str, slen))
711 * resctrl_resource_exists - Check if a resource is supported.
712 * @resource: Resctrl resource (e.g., MB, L3, L2, L3_MON, etc.)
714 * Return: True if the resource is supported, else false. False is
715 * also returned if resctrl FS is not mounted.
717 bool resctrl_resource_exists(const char *resource)
719 char res_path[PATH_MAX];
726 ret = find_resctrl_mount(NULL);
730 snprintf(res_path, sizeof(res_path), "%s/%s", INFO_PATH, resource);
732 if (stat(res_path, &statbuf))
739 * resctrl_mon_feature_exists - Check if requested monitoring feature is valid.
740 * @resource: Resource that uses the mon_features file. Currently only L3_MON
742 * @feature: Required monitor feature (in mon_features file).
744 * Return: True if the feature is supported, else false.
746 bool resctrl_mon_feature_exists(const char *resource, const char *feature)
748 char res_path[PATH_MAX];
752 if (!feature || !resource)
755 snprintf(res_path, sizeof(res_path), "%s/%s/mon_features", INFO_PATH, resource);
756 inf = fopen(res_path, "r");
760 res = fgrep(inf, feature);
768 * resource_info_file_exists - Check if a file is present inside
769 * /sys/fs/resctrl/info/@resource.
770 * @resource: Required resource (Eg: MB, L3, L2, etc.)
771 * @file: Required file.
773 * Return: True if the /sys/fs/resctrl/info/@resource/@file exists, else false.
775 bool resource_info_file_exists(const char *resource, const char *file)
777 char res_path[PATH_MAX];
780 if (!file || !resource)
783 snprintf(res_path, sizeof(res_path), "%s/%s/%s", INFO_PATH, resource,
786 if (stat(res_path, &statbuf))
792 bool test_resource_feature_check(const struct resctrl_test *test)
794 return resctrl_resource_exists(test->resource);
797 int filter_dmesg(void)
814 dup2(pipefds[1], STDOUT_FILENO);
815 execlp("dmesg", "dmesg", NULL);
816 ksft_perror("Executing dmesg");
820 fp = fdopen(pipefds[0], "r");
822 ksft_perror("fdopen(pipe)");
828 while (fgets(line, 1024, fp)) {
829 if (strstr(line, "intel_rdt:"))
830 ksft_print_msg("dmesg: %s", line);
831 if (strstr(line, "resctrl:"))
832 ksft_print_msg("dmesg: %s", line);
835 waitpid(pid, NULL, 0);
840 int validate_bw_report_request(char *bw_report)
842 if (strcmp(bw_report, "reads") == 0)
844 if (strcmp(bw_report, "writes") == 0)
846 if (strcmp(bw_report, "nt-writes") == 0) {
847 strcpy(bw_report, "writes");
850 if (strcmp(bw_report, "total") == 0)
853 fprintf(stderr, "Requested iMC B/W report type unavailable\n");
858 int perf_event_open(struct perf_event_attr *hw_event, pid_t pid, int cpu,
859 int group_fd, unsigned long flags)
863 ret = syscall(__NR_perf_event_open, hw_event, pid, cpu,
868 unsigned int count_bits(unsigned long n)
870 unsigned int count = 0;