diff options
Diffstat (limited to 'tools/testing/selftests/resctrl/resctrlfs.c')
| -rw-r--r-- | tools/testing/selftests/resctrl/resctrlfs.c | 991 |
1 files changed, 991 insertions, 0 deletions
diff --git a/tools/testing/selftests/resctrl/resctrlfs.c b/tools/testing/selftests/resctrl/resctrlfs.c new file mode 100644 index 000000000000..195f04c4d158 --- /dev/null +++ b/tools/testing/selftests/resctrl/resctrlfs.c @@ -0,0 +1,991 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Basic resctrl file system operations + * + * Copyright (C) 2018 Intel Corporation + * + * Authors: + * Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>, + * Fenghua Yu <fenghua.yu@intel.com> + */ +#include <fcntl.h> +#include <limits.h> + +#include "resctrl.h" + +int snc_unreliable; + +static int find_resctrl_mount(char *buffer) +{ + FILE *mounts; + char line[256], *fs, *mntpoint; + + mounts = fopen("/proc/mounts", "r"); + if (!mounts) { + ksft_perror("/proc/mounts"); + return -ENXIO; + } + while (!feof(mounts)) { + if (!fgets(line, 256, mounts)) + break; + fs = strtok(line, " \t"); + if (!fs) + continue; + mntpoint = strtok(NULL, " \t"); + if (!mntpoint) + continue; + fs = strtok(NULL, " \t"); + if (!fs) + continue; + if (strcmp(fs, "resctrl")) + continue; + + fclose(mounts); + if (buffer) + strncpy(buffer, mntpoint, 256); + + return 0; + } + + fclose(mounts); + + return -ENOENT; +} + +/* + * mount_resctrlfs - Mount resctrl FS at /sys/fs/resctrl + * + * Mounts resctrl FS. Fails if resctrl FS is already mounted to avoid + * pre-existing settings interfering with the test results. + * + * Return: 0 on success, < 0 on error. + */ +int mount_resctrlfs(void) +{ + int ret; + + ret = find_resctrl_mount(NULL); + if (ret != -ENOENT) + return -1; + + ksft_print_msg("Mounting resctrl to \"%s\"\n", RESCTRL_PATH); + ret = mount("resctrl", RESCTRL_PATH, "resctrl", 0, NULL); + if (ret) + ksft_perror("mount"); + + return ret; +} + +int umount_resctrlfs(void) +{ + char mountpoint[256]; + int ret; + + ret = find_resctrl_mount(mountpoint); + if (ret == -ENOENT) + return 0; + if (ret) + return ret; + + if (umount(mountpoint)) { + ksft_perror("Unable to umount resctrl"); + + return -1; + } + + return 0; +} + +/* + * get_cache_level - Convert cache level from string to integer + * @cache_type: Cache level as string + * + * Return: cache level as integer or -1 if @cache_type is invalid. + */ +static int get_cache_level(const char *cache_type) +{ + if (!strcmp(cache_type, "L3")) + return 3; + if (!strcmp(cache_type, "L2")) + return 2; + + ksft_print_msg("Invalid cache level\n"); + return -1; +} + +static int get_resource_cache_level(const char *resource) +{ + /* "MB" use L3 (LLC) as resource */ + if (!strcmp(resource, "MB")) + return 3; + return get_cache_level(resource); +} + +/* + * get_domain_id - Get resctrl domain ID for a specified CPU + * @resource: resource name + * @cpu_no: CPU number + * @domain_id: domain ID (cache ID; for MB, L3 cache ID) + * + * Return: >= 0 on success, < 0 on failure. + */ +int get_domain_id(const char *resource, int cpu_no, int *domain_id) +{ + char phys_pkg_path[1024]; + int cache_num; + FILE *fp; + + cache_num = get_resource_cache_level(resource); + if (cache_num < 0) + return cache_num; + + sprintf(phys_pkg_path, "%s%d/cache/index%d/id", PHYS_ID_PATH, cpu_no, cache_num); + + fp = fopen(phys_pkg_path, "r"); + if (!fp) { + ksft_perror("Failed to open cache id file"); + + return -1; + } + if (fscanf(fp, "%d", domain_id) <= 0) { + ksft_perror("Could not get domain ID"); + fclose(fp); + + return -1; + } + fclose(fp); + + return 0; +} + +/* + * Count number of CPUs in a /sys bitmap + */ +static unsigned int count_sys_bitmap_bits(char *name) +{ + FILE *fp = fopen(name, "r"); + int count = 0, c; + + if (!fp) + return 0; + + while ((c = fgetc(fp)) != EOF) { + if (!isxdigit(c)) + continue; + switch (c) { + case 'f': + count++; + fallthrough; + case '7': case 'b': case 'd': case 'e': + count++; + fallthrough; + case '3': case '5': case '6': case '9': case 'a': case 'c': + count++; + fallthrough; + case '1': case '2': case '4': case '8': + count++; + break; + } + } + fclose(fp); + + return count; +} + +static bool cpus_offline_empty(void) +{ + char offline_cpus_str[64]; + FILE *fp; + + fp = fopen("/sys/devices/system/cpu/offline", "r"); + if (!fp) { + ksft_perror("Could not open /sys/devices/system/cpu/offline"); + return 0; + } + + if (fscanf(fp, "%63s", offline_cpus_str) < 0) { + if (!errno) { + fclose(fp); + return 1; + } + ksft_perror("Could not read /sys/devices/system/cpu/offline"); + } + + fclose(fp); + + return 0; +} + +/* + * Detect SNC by comparing #CPUs in node0 with #CPUs sharing LLC with CPU0. + * If any CPUs are offline declare the detection as unreliable. + */ +int snc_nodes_per_l3_cache(void) +{ + int node_cpus, cache_cpus; + static int snc_mode; + + if (!snc_mode) { + snc_mode = 1; + if (!cpus_offline_empty()) { + ksft_print_msg("Runtime SNC detection unreliable due to offline CPUs.\n"); + ksft_print_msg("Setting SNC mode to disabled.\n"); + snc_unreliable = 1; + return snc_mode; + } + node_cpus = count_sys_bitmap_bits("/sys/devices/system/node/node0/cpumap"); + cache_cpus = count_sys_bitmap_bits("/sys/devices/system/cpu/cpu0/cache/index3/shared_cpu_map"); + + if (!node_cpus || !cache_cpus) { + ksft_print_msg("Could not determine Sub-NUMA Cluster mode.\n"); + snc_unreliable = 1; + return snc_mode; + } + snc_mode = cache_cpus / node_cpus; + + if (snc_mode > 1) + ksft_print_msg("SNC-%d mode discovered.\n", snc_mode); + } + + return snc_mode; +} + +/* + * get_cache_size - Get cache size for a specified CPU + * @cpu_no: CPU number + * @cache_type: Cache level L2/L3 + * @cache_size: pointer to cache_size + * + * Return: = 0 on success, < 0 on failure. + */ +int get_cache_size(int cpu_no, const char *cache_type, unsigned long *cache_size) +{ + char cache_path[1024], cache_str[64]; + int length, i, cache_num; + FILE *fp; + + cache_num = get_cache_level(cache_type); + if (cache_num < 0) + return cache_num; + + sprintf(cache_path, "/sys/bus/cpu/devices/cpu%d/cache/index%d/size", + cpu_no, cache_num); + fp = fopen(cache_path, "r"); + if (!fp) { + ksft_perror("Failed to open cache size"); + + return -1; + } + if (fscanf(fp, "%63s", cache_str) <= 0) { + ksft_perror("Could not get cache_size"); + fclose(fp); + + return -1; + } + fclose(fp); + + length = (int)strlen(cache_str); + + *cache_size = 0; + + for (i = 0; i < length; i++) { + if ((cache_str[i] >= '0') && (cache_str[i] <= '9')) + + *cache_size = *cache_size * 10 + (cache_str[i] - '0'); + + else if (cache_str[i] == 'K') + + *cache_size = *cache_size * 1024; + + else if (cache_str[i] == 'M') + + *cache_size = *cache_size * 1024 * 1024; + + else + break; + } + + /* + * The amount of cache represented by each bit in the masks + * in the schemata file is reduced by a factor equal to SNC + * nodes per L3 cache. + * E.g. on a SNC-2 system with a 100MB L3 cache a test that + * allocates memory from its local SNC node (default behavior + * without using libnuma) will only see 50 MB llc_occupancy + * with a fully populated L3 mask in the schemata file. + */ + if (cache_num == 3) + *cache_size /= snc_nodes_per_l3_cache(); + return 0; +} + +#define CORE_SIBLINGS_PATH "/sys/bus/cpu/devices/cpu" + +/* + * get_bit_mask - Get bit mask from given file + * @filename: File containing the mask + * @mask: The bit mask returned as unsigned long + * + * Return: = 0 on success, < 0 on failure. + */ +static int get_bit_mask(const char *filename, unsigned long *mask) +{ + FILE *fp; + + if (!filename || !mask) + return -1; + + fp = fopen(filename, "r"); + if (!fp) { + ksft_print_msg("Failed to open bit mask file '%s': %s\n", + filename, strerror(errno)); + return -1; + } + + if (fscanf(fp, "%lx", mask) <= 0) { + ksft_print_msg("Could not read bit mask file '%s': %s\n", + filename, strerror(errno)); + fclose(fp); + + return -1; + } + fclose(fp); + + return 0; +} + +/* + * resource_info_unsigned_get - Read an unsigned value from + * /sys/fs/resctrl/info/@resource/@filename + * @resource: Resource name that matches directory name in + * /sys/fs/resctrl/info + * @filename: File in /sys/fs/resctrl/info/@resource + * @val: Contains read value on success. + * + * Return: = 0 on success, < 0 on failure. On success the read + * value is saved into @val. + */ +int resource_info_unsigned_get(const char *resource, const char *filename, + unsigned int *val) +{ + char file_path[PATH_MAX]; + FILE *fp; + + snprintf(file_path, sizeof(file_path), "%s/%s/%s", INFO_PATH, resource, + filename); + + fp = fopen(file_path, "r"); + if (!fp) { + ksft_print_msg("Error opening %s: %m\n", file_path); + return -1; + } + + if (fscanf(fp, "%u", val) <= 0) { + ksft_print_msg("Could not get contents of %s: %m\n", file_path); + fclose(fp); + return -1; + } + + fclose(fp); + return 0; +} + +/* + * create_bit_mask- Create bit mask from start, len pair + * @start: LSB of the mask + * @len Number of bits in the mask + */ +unsigned long create_bit_mask(unsigned int start, unsigned int len) +{ + return ((1UL << len) - 1UL) << start; +} + +/* + * count_contiguous_bits - Returns the longest train of bits in a bit mask + * @val A bit mask + * @start The location of the least-significant bit of the longest train + * + * Return: The length of the contiguous bits in the longest train of bits + */ +unsigned int count_contiguous_bits(unsigned long val, unsigned int *start) +{ + unsigned long last_val; + unsigned int count = 0; + + while (val) { + last_val = val; + val &= (val >> 1); + count++; + } + + if (start) { + if (count) + *start = ffsl(last_val) - 1; + else + *start = 0; + } + + return count; +} + +/* + * get_full_cbm - Get full Cache Bit Mask (CBM) + * @cache_type: Cache type as "L2" or "L3" + * @mask: Full cache bit mask representing the maximal portion of cache + * available for allocation, returned as unsigned long. + * + * Return: = 0 on success, < 0 on failure. + */ +int get_full_cbm(const char *cache_type, unsigned long *mask) +{ + char cbm_path[PATH_MAX]; + int ret; + + if (!cache_type) + return -1; + + snprintf(cbm_path, sizeof(cbm_path), "%s/%s/cbm_mask", + INFO_PATH, cache_type); + + ret = get_bit_mask(cbm_path, mask); + if (ret || !*mask) + return -1; + + return 0; +} + +/* + * get_shareable_mask - Get shareable mask from shareable_bits + * @cache_type: Cache type as "L2" or "L3" + * @shareable_mask: Shareable mask returned as unsigned long + * + * Return: = 0 on success, < 0 on failure. + */ +static int get_shareable_mask(const char *cache_type, unsigned long *shareable_mask) +{ + char mask_path[PATH_MAX]; + + if (!cache_type) + return -1; + + snprintf(mask_path, sizeof(mask_path), "%s/%s/shareable_bits", + INFO_PATH, cache_type); + + return get_bit_mask(mask_path, shareable_mask); +} + +/* + * get_mask_no_shareable - Get Cache Bit Mask (CBM) without shareable bits + * @cache_type: Cache type as "L2" or "L3" + * @mask: The largest exclusive portion of the cache out of the + * full CBM, returned as unsigned long + * + * Parts of a cache may be shared with other devices such as GPU. This function + * calculates the largest exclusive portion of the cache where no other devices + * besides CPU have access to the cache portion. + * + * Return: = 0 on success, < 0 on failure. + */ +int get_mask_no_shareable(const char *cache_type, unsigned long *mask) +{ + unsigned long full_mask, shareable_mask; + unsigned int start, len; + + if (get_full_cbm(cache_type, &full_mask) < 0) + return -1; + if (get_shareable_mask(cache_type, &shareable_mask) < 0) + return -1; + + len = count_contiguous_bits(full_mask & ~shareable_mask, &start); + if (!len) + return -1; + + *mask = create_bit_mask(start, len); + + return 0; +} + +/* + * taskset_benchmark - Taskset PID (i.e. benchmark) to a specified cpu + * @bm_pid: PID that should be binded + * @cpu_no: CPU number at which the PID would be binded + * @old_affinity: When not NULL, set to old CPU affinity + * + * Return: 0 on success, < 0 on error. + */ +int taskset_benchmark(pid_t bm_pid, int cpu_no, cpu_set_t *old_affinity) +{ + cpu_set_t my_set; + + if (old_affinity) { + CPU_ZERO(old_affinity); + if (sched_getaffinity(bm_pid, sizeof(*old_affinity), + old_affinity)) { + ksft_perror("Unable to read CPU affinity"); + return -1; + } + } + + CPU_ZERO(&my_set); + CPU_SET(cpu_no, &my_set); + + if (sched_setaffinity(bm_pid, sizeof(cpu_set_t), &my_set)) { + ksft_perror("Unable to taskset benchmark"); + + return -1; + } + + return 0; +} + +/* + * taskset_restore - Taskset PID to the earlier CPU affinity + * @bm_pid: PID that should be reset + * @old_affinity: The old CPU affinity to restore + * + * Return: 0 on success, < 0 on error. + */ +int taskset_restore(pid_t bm_pid, cpu_set_t *old_affinity) +{ + if (sched_setaffinity(bm_pid, sizeof(*old_affinity), old_affinity)) { + ksft_perror("Unable to restore CPU affinity"); + return -1; + } + + return 0; +} + +/* + * create_grp - Create a group only if one doesn't exist + * @grp_name: Name of the group + * @grp: Full path and name of the group + * @parent_grp: Full path and name of the parent group + * + * Creates a group @grp_name if it does not exist yet. If @grp_name is NULL, + * it is interpreted as the root group which always results in success. + * + * Return: 0 on success, < 0 on error. + */ +static int create_grp(const char *grp_name, char *grp, const char *parent_grp) +{ + int found_grp = 0; + struct dirent *ep; + DIR *dp; + + if (!grp_name) + return 0; + + /* Check if requested grp exists or not */ + dp = opendir(parent_grp); + if (dp) { + while ((ep = readdir(dp)) != NULL) { + if (strcmp(ep->d_name, grp_name) == 0) + found_grp = 1; + } + closedir(dp); + } else { + ksft_perror("Unable to open resctrl for group"); + + return -1; + } + + /* Requested grp doesn't exist, hence create it */ + if (found_grp == 0) { + if (mkdir(grp, 0) == -1) { + ksft_perror("Unable to create group"); + + return -1; + } + } + + return 0; +} + +static int write_pid_to_tasks(char *tasks, pid_t pid) +{ + FILE *fp; + + fp = fopen(tasks, "w"); + if (!fp) { + ksft_perror("Failed to open tasks file"); + + return -1; + } + if (fprintf(fp, "%d\n", (int)pid) < 0) { + ksft_print_msg("Failed to write pid to tasks file\n"); + fclose(fp); + + return -1; + } + fclose(fp); + + return 0; +} + +/* + * write_bm_pid_to_resctrl - Write a PID (i.e. benchmark) to resctrl FS + * @bm_pid: PID that should be written + * @ctrlgrp: Name of the control monitor group (con_mon grp) + * @mongrp: Name of the monitor group (mon grp) + * + * If a con_mon grp is requested, create it and write pid to it, otherwise + * write pid to root con_mon grp. + * If a mon grp is requested, create it and write pid to it, otherwise + * pid is not written, this means that pid is in con_mon grp and hence + * should consult con_mon grp's mon_data directory for results. + * + * Return: 0 on success, < 0 on error. + */ +int write_bm_pid_to_resctrl(pid_t bm_pid, const char *ctrlgrp, const char *mongrp) +{ + char controlgroup[128], monitorgroup[512], monitorgroup_p[256]; + char tasks[1024]; + int ret = 0; + + if (ctrlgrp) + sprintf(controlgroup, "%s/%s", RESCTRL_PATH, ctrlgrp); + else + sprintf(controlgroup, "%s", RESCTRL_PATH); + + /* Create control and monitoring group and write pid into it */ + ret = create_grp(ctrlgrp, controlgroup, RESCTRL_PATH); + if (ret) + goto out; + sprintf(tasks, "%s/tasks", controlgroup); + ret = write_pid_to_tasks(tasks, bm_pid); + if (ret) + goto out; + + /* Create monitor group and write pid into if it is used */ + if (mongrp) { + sprintf(monitorgroup_p, "%s/mon_groups", controlgroup); + sprintf(monitorgroup, "%s/%s", monitorgroup_p, mongrp); + ret = create_grp(mongrp, monitorgroup, monitorgroup_p); + if (ret) + goto out; + + sprintf(tasks, "%s/mon_groups/%s/tasks", + controlgroup, mongrp); + ret = write_pid_to_tasks(tasks, bm_pid); + if (ret) + goto out; + } + +out: + ksft_print_msg("Writing benchmark parameters to resctrl FS\n"); + if (ret) + ksft_print_msg("Failed writing to resctrlfs\n"); + + return ret; +} + +/* + * write_schemata - Update schemata of a con_mon grp + * @ctrlgrp: Name of the con_mon grp + * @schemata: Schemata that should be updated to + * @cpu_no: CPU number that the benchmark PID is binded to + * @resource: Resctrl resource (Eg: MB, L3, L2, etc.) + * + * Update schemata of a con_mon grp *only* if requested resctrl resource is + * allocation type + * + * Return: 0 on success, < 0 on error. + */ +int write_schemata(const char *ctrlgrp, char *schemata, int cpu_no, + const char *resource) +{ + char controlgroup[1024], reason[128], schema[1024] = {}; + int domain_id, fd, schema_len, ret = 0; + + if (!schemata) { + ksft_print_msg("Skipping empty schemata update\n"); + + return -1; + } + + if (get_domain_id(resource, cpu_no, &domain_id) < 0) { + sprintf(reason, "Failed to get domain ID"); + ret = -1; + + goto out; + } + + if (ctrlgrp) + sprintf(controlgroup, "%s/%s/schemata", RESCTRL_PATH, ctrlgrp); + else + sprintf(controlgroup, "%s/schemata", RESCTRL_PATH); + + schema_len = snprintf(schema, sizeof(schema), "%s:%d=%s\n", + resource, domain_id, schemata); + if (schema_len < 0 || schema_len >= sizeof(schema)) { + snprintf(reason, sizeof(reason), + "snprintf() failed with return value : %d", schema_len); + ret = -1; + goto out; + } + + fd = open(controlgroup, O_WRONLY); + if (fd < 0) { + snprintf(reason, sizeof(reason), + "open() failed : %s", strerror(errno)); + ret = -1; + + goto err_schema_not_empty; + } + if (write(fd, schema, schema_len) < 0) { + snprintf(reason, sizeof(reason), + "write() failed : %s", strerror(errno)); + close(fd); + ret = -1; + + goto err_schema_not_empty; + } + close(fd); + +err_schema_not_empty: + schema[schema_len - 1] = 0; +out: + ksft_print_msg("Write schema \"%s\" to resctrl FS%s%s\n", + schema, ret ? " # " : "", + ret ? reason : ""); + + return ret; +} + +bool check_resctrlfs_support(void) +{ + FILE *inf = fopen("/proc/filesystems", "r"); + DIR *dp; + char *res; + bool ret = false; + + if (!inf) + return false; + + res = fgrep(inf, "nodev\tresctrl\n"); + + if (res) { + ret = true; + free(res); + } + + fclose(inf); + + ksft_print_msg("%s Check kernel supports resctrl filesystem\n", + ret ? "Pass:" : "Fail:"); + + if (!ret) + return ret; + + dp = opendir(RESCTRL_PATH); + ksft_print_msg("%s Check resctrl mountpoint \"%s\" exists\n", + dp ? "Pass:" : "Fail:", RESCTRL_PATH); + if (dp) + closedir(dp); + + ksft_print_msg("resctrl filesystem %s mounted\n", + find_resctrl_mount(NULL) ? "not" : "is"); + + return ret; +} + +char *fgrep(FILE *inf, const char *str) +{ + char line[256]; + int slen = strlen(str); + + while (!feof(inf)) { + if (!fgets(line, 256, inf)) + break; + if (strncmp(line, str, slen)) + continue; + + return strdup(line); + } + + return NULL; +} + +/* + * resctrl_resource_exists - Check if a resource is supported. + * @resource: Resctrl resource (e.g., MB, L3, L2, L3_MON, etc.) + * + * Return: True if the resource is supported, else false. False is + * also returned if resctrl FS is not mounted. + */ +bool resctrl_resource_exists(const char *resource) +{ + char res_path[PATH_MAX]; + struct stat statbuf; + int ret; + + if (!resource) + return false; + + ret = find_resctrl_mount(NULL); + if (ret) + return false; + + snprintf(res_path, sizeof(res_path), "%s/%s", INFO_PATH, resource); + + if (stat(res_path, &statbuf)) + return false; + + return true; +} + +/* + * resctrl_mon_feature_exists - Check if requested monitoring feature is valid. + * @resource: Resource that uses the mon_features file. Currently only L3_MON + * is valid. + * @feature: Required monitor feature (in mon_features file). + * + * Return: True if the feature is supported, else false. + */ +bool resctrl_mon_feature_exists(const char *resource, const char *feature) +{ + char res_path[PATH_MAX]; + char *res; + FILE *inf; + + if (!feature || !resource) + return false; + + snprintf(res_path, sizeof(res_path), "%s/%s/mon_features", INFO_PATH, resource); + inf = fopen(res_path, "r"); + if (!inf) + return false; + + res = fgrep(inf, feature); + free(res); + fclose(inf); + + return !!res; +} + +/* + * resource_info_file_exists - Check if a file is present inside + * /sys/fs/resctrl/info/@resource. + * @resource: Required resource (Eg: MB, L3, L2, etc.) + * @file: Required file. + * + * Return: True if the /sys/fs/resctrl/info/@resource/@file exists, else false. + */ +bool resource_info_file_exists(const char *resource, const char *file) +{ + char res_path[PATH_MAX]; + struct stat statbuf; + + if (!file || !resource) + return false; + + snprintf(res_path, sizeof(res_path), "%s/%s/%s", INFO_PATH, resource, + file); + + if (stat(res_path, &statbuf)) + return false; + + return true; +} + +bool test_resource_feature_check(const struct resctrl_test *test) +{ + return resctrl_resource_exists(test->resource); +} + +int filter_dmesg(void) +{ + char line[1024]; + FILE *fp; + int pipefds[2]; + pid_t pid; + int ret; + + ret = pipe(pipefds); + if (ret) { + ksft_perror("pipe"); + return ret; + } + fflush(stdout); + pid = fork(); + if (pid == 0) { + close(pipefds[0]); + dup2(pipefds[1], STDOUT_FILENO); + execlp("dmesg", "dmesg", NULL); + ksft_perror("Executing dmesg"); + exit(1); + } + close(pipefds[1]); + fp = fdopen(pipefds[0], "r"); + if (!fp) { + ksft_perror("fdopen(pipe)"); + kill(pid, SIGTERM); + + return -1; + } + + while (fgets(line, 1024, fp)) { + if (strstr(line, "intel_rdt:")) + ksft_print_msg("dmesg: %s", line); + if (strstr(line, "resctrl:")) + ksft_print_msg("dmesg: %s", line); + } + fclose(fp); + waitpid(pid, NULL, 0); + + return 0; +} + +int perf_event_open(struct perf_event_attr *hw_event, pid_t pid, int cpu, + int group_fd, unsigned long flags) +{ + int ret; + + ret = syscall(__NR_perf_event_open, hw_event, pid, cpu, + group_fd, flags); + return ret; +} + +unsigned int count_bits(unsigned long n) +{ + unsigned int count = 0; + + while (n) { + count += n & 1; + n >>= 1; + } + + return count; +} + +/** + * snc_kernel_support - Check for existence of mon_sub_L3_00 file that indicates + * SNC resctrl support on the kernel side. + * + * Return: 0 if not supported, 1 if SNC is disabled or SNC discovery is + * unreliable or SNC is both enabled and supported. + */ +int snc_kernel_support(void) +{ + char node_path[PATH_MAX]; + struct stat statbuf; + int ret; + + ret = snc_nodes_per_l3_cache(); + /* + * If SNC is disabled then its kernel support isn't important. If SNC + * got disabled because the discovery process was unreliable the + * snc_unreliable variable was set. It can be used to verify the SNC + * discovery reliability elsewhere in the selftest. + */ + if (ret == 1) + return ret; + + snprintf(node_path, sizeof(node_path), "%s/%s", RESCTRL_PATH, + "mon_data/mon_L3_00/mon_sub_L3_00"); + + if (!stat(node_path, &statbuf)) + return 1; + + return 0; +} |