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-rw-r--r--tools/tracing/rtla/src/utils.c819
1 files changed, 819 insertions, 0 deletions
diff --git a/tools/tracing/rtla/src/utils.c b/tools/tracing/rtla/src/utils.c
new file mode 100644
index 0000000000..c769d7b384
--- /dev/null
+++ b/tools/tracing/rtla/src/utils.c
@@ -0,0 +1,819 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2021 Red Hat Inc, Daniel Bristot de Oliveira <bristot@kernel.org>
+ */
+
+#define _GNU_SOURCE
+#include <dirent.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <ctype.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <sched.h>
+#include <stdio.h>
+
+#include "utils.h"
+
+#define MAX_MSG_LENGTH 1024
+int config_debug;
+
+/*
+ * err_msg - print an error message to the stderr
+ */
+void err_msg(const char *fmt, ...)
+{
+ char message[MAX_MSG_LENGTH];
+ va_list ap;
+
+ va_start(ap, fmt);
+ vsnprintf(message, sizeof(message), fmt, ap);
+ va_end(ap);
+
+ fprintf(stderr, "%s", message);
+}
+
+/*
+ * debug_msg - print a debug message to stderr if debug is set
+ */
+void debug_msg(const char *fmt, ...)
+{
+ char message[MAX_MSG_LENGTH];
+ va_list ap;
+
+ if (!config_debug)
+ return;
+
+ va_start(ap, fmt);
+ vsnprintf(message, sizeof(message), fmt, ap);
+ va_end(ap);
+
+ fprintf(stderr, "%s", message);
+}
+
+/*
+ * get_llong_from_str - get a long long int from a string
+ */
+long long get_llong_from_str(char *start)
+{
+ long long value;
+ char *end;
+
+ errno = 0;
+ value = strtoll(start, &end, 10);
+ if (errno || start == end)
+ return -1;
+
+ return value;
+}
+
+/*
+ * get_duration - fill output with a human readable duration since start_time
+ */
+void get_duration(time_t start_time, char *output, int output_size)
+{
+ time_t now = time(NULL);
+ struct tm *tm_info;
+ time_t duration;
+
+ duration = difftime(now, start_time);
+ tm_info = gmtime(&duration);
+
+ snprintf(output, output_size, "%3d %02d:%02d:%02d",
+ tm_info->tm_yday,
+ tm_info->tm_hour,
+ tm_info->tm_min,
+ tm_info->tm_sec);
+}
+
+/*
+ * parse_cpu_set - parse a cpu_list filling cpu_set_t argument
+ *
+ * Receives a cpu list, like 1-3,5 (cpus 1, 2, 3, 5), and then set
+ * filling cpu_set_t argument.
+ *
+ * Returns 1 on success, 0 otherwise.
+ */
+int parse_cpu_set(char *cpu_list, cpu_set_t *set)
+{
+ const char *p;
+ int end_cpu;
+ int nr_cpus;
+ int cpu;
+ int i;
+
+ CPU_ZERO(set);
+
+ nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
+
+ for (p = cpu_list; *p; ) {
+ cpu = atoi(p);
+ if (cpu < 0 || (!cpu && *p != '0') || cpu >= nr_cpus)
+ goto err;
+
+ while (isdigit(*p))
+ p++;
+ if (*p == '-') {
+ p++;
+ end_cpu = atoi(p);
+ if (end_cpu < cpu || (!end_cpu && *p != '0') || end_cpu >= nr_cpus)
+ goto err;
+ while (isdigit(*p))
+ p++;
+ } else
+ end_cpu = cpu;
+
+ if (cpu == end_cpu) {
+ debug_msg("cpu_set: adding cpu %d\n", cpu);
+ CPU_SET(cpu, set);
+ } else {
+ for (i = cpu; i <= end_cpu; i++) {
+ debug_msg("cpu_set: adding cpu %d\n", i);
+ CPU_SET(i, set);
+ }
+ }
+
+ if (*p == ',')
+ p++;
+ }
+
+ return 0;
+err:
+ debug_msg("Error parsing the cpu set %s\n", cpu_list);
+ return 1;
+}
+
+/*
+ * parse_duration - parse duration with s/m/h/d suffix converting it to seconds
+ */
+long parse_seconds_duration(char *val)
+{
+ char *end;
+ long t;
+
+ t = strtol(val, &end, 10);
+
+ if (end) {
+ switch (*end) {
+ case 's':
+ case 'S':
+ break;
+ case 'm':
+ case 'M':
+ t *= 60;
+ break;
+ case 'h':
+ case 'H':
+ t *= 60 * 60;
+ break;
+
+ case 'd':
+ case 'D':
+ t *= 24 * 60 * 60;
+ break;
+ }
+ }
+
+ return t;
+}
+
+/*
+ * parse_ns_duration - parse duration with ns/us/ms/s converting it to nanoseconds
+ */
+long parse_ns_duration(char *val)
+{
+ char *end;
+ long t;
+
+ t = strtol(val, &end, 10);
+
+ if (end) {
+ if (!strncmp(end, "ns", 2)) {
+ return t;
+ } else if (!strncmp(end, "us", 2)) {
+ t *= 1000;
+ return t;
+ } else if (!strncmp(end, "ms", 2)) {
+ t *= 1000 * 1000;
+ return t;
+ } else if (!strncmp(end, "s", 1)) {
+ t *= 1000 * 1000 * 1000;
+ return t;
+ }
+ return -1;
+ }
+
+ return t;
+}
+
+/*
+ * This is a set of helper functions to use SCHED_DEADLINE.
+ */
+#ifdef __x86_64__
+# define __NR_sched_setattr 314
+# define __NR_sched_getattr 315
+#elif __i386__
+# define __NR_sched_setattr 351
+# define __NR_sched_getattr 352
+#elif __arm__
+# define __NR_sched_setattr 380
+# define __NR_sched_getattr 381
+#elif __aarch64__ || __riscv
+# define __NR_sched_setattr 274
+# define __NR_sched_getattr 275
+#elif __powerpc__
+# define __NR_sched_setattr 355
+# define __NR_sched_getattr 356
+#elif __s390x__
+# define __NR_sched_setattr 345
+# define __NR_sched_getattr 346
+#endif
+
+#define SCHED_DEADLINE 6
+
+static inline int sched_setattr(pid_t pid, const struct sched_attr *attr,
+ unsigned int flags) {
+ return syscall(__NR_sched_setattr, pid, attr, flags);
+}
+
+static inline int sched_getattr(pid_t pid, struct sched_attr *attr,
+ unsigned int size, unsigned int flags)
+{
+ return syscall(__NR_sched_getattr, pid, attr, size, flags);
+}
+
+int __set_sched_attr(int pid, struct sched_attr *attr)
+{
+ int flags = 0;
+ int retval;
+
+ retval = sched_setattr(pid, attr, flags);
+ if (retval < 0) {
+ err_msg("Failed to set sched attributes to the pid %d: %s\n",
+ pid, strerror(errno));
+ return 1;
+ }
+
+ return 0;
+}
+
+/*
+ * procfs_is_workload_pid - check if a procfs entry contains a comm_prefix* comm
+ *
+ * Check if the procfs entry is a directory of a process, and then check if the
+ * process has a comm with the prefix set in char *comm_prefix. As the
+ * current users of this function only check for kernel threads, there is no
+ * need to check for the threads for the process.
+ *
+ * Return: True if the proc_entry contains a comm file with comm_prefix*.
+ * Otherwise returns false.
+ */
+static int procfs_is_workload_pid(const char *comm_prefix, struct dirent *proc_entry)
+{
+ char buffer[MAX_PATH];
+ int comm_fd, retval;
+ char *t_name;
+
+ if (proc_entry->d_type != DT_DIR)
+ return 0;
+
+ if (*proc_entry->d_name == '.')
+ return 0;
+
+ /* check if the string is a pid */
+ for (t_name = proc_entry->d_name; t_name; t_name++) {
+ if (!isdigit(*t_name))
+ break;
+ }
+
+ if (*t_name != '\0')
+ return 0;
+
+ snprintf(buffer, MAX_PATH, "/proc/%s/comm", proc_entry->d_name);
+ comm_fd = open(buffer, O_RDONLY);
+ if (comm_fd < 0)
+ return 0;
+
+ memset(buffer, 0, MAX_PATH);
+ retval = read(comm_fd, buffer, MAX_PATH);
+
+ close(comm_fd);
+
+ if (retval <= 0)
+ return 0;
+
+ retval = strncmp(comm_prefix, buffer, strlen(comm_prefix));
+ if (retval)
+ return 0;
+
+ /* comm already have \n */
+ debug_msg("Found workload pid:%s comm:%s", proc_entry->d_name, buffer);
+
+ return 1;
+}
+
+/*
+ * set_comm_sched_attr - set sched params to threads starting with char *comm_prefix
+ *
+ * This function uses procfs to list the currently running threads and then set the
+ * sched_attr *attr to the threads that start with char *comm_prefix. It is
+ * mainly used to set the priority to the kernel threads created by the
+ * tracers.
+ */
+int set_comm_sched_attr(const char *comm_prefix, struct sched_attr *attr)
+{
+ struct dirent *proc_entry;
+ DIR *procfs;
+ int retval;
+
+ if (strlen(comm_prefix) >= MAX_PATH) {
+ err_msg("Command prefix is too long: %d < strlen(%s)\n",
+ MAX_PATH, comm_prefix);
+ return 1;
+ }
+
+ procfs = opendir("/proc");
+ if (!procfs) {
+ err_msg("Could not open procfs\n");
+ return 1;
+ }
+
+ while ((proc_entry = readdir(procfs))) {
+
+ retval = procfs_is_workload_pid(comm_prefix, proc_entry);
+ if (!retval)
+ continue;
+
+ /* procfs_is_workload_pid confirmed it is a pid */
+ retval = __set_sched_attr(atoi(proc_entry->d_name), attr);
+ if (retval) {
+ err_msg("Error setting sched attributes for pid:%s\n", proc_entry->d_name);
+ goto out_err;
+ }
+
+ debug_msg("Set sched attributes for pid:%s\n", proc_entry->d_name);
+ }
+ return 0;
+
+out_err:
+ closedir(procfs);
+ return 1;
+}
+
+#define INVALID_VAL (~0L)
+static long get_long_ns_after_colon(char *start)
+{
+ long val = INVALID_VAL;
+
+ /* find the ":" */
+ start = strstr(start, ":");
+ if (!start)
+ return -1;
+
+ /* skip ":" */
+ start++;
+ val = parse_ns_duration(start);
+
+ return val;
+}
+
+static long get_long_after_colon(char *start)
+{
+ long val = INVALID_VAL;
+
+ /* find the ":" */
+ start = strstr(start, ":");
+ if (!start)
+ return -1;
+
+ /* skip ":" */
+ start++;
+ val = get_llong_from_str(start);
+
+ return val;
+}
+
+/*
+ * parse priority in the format:
+ * SCHED_OTHER:
+ * o:<prio>
+ * O:<prio>
+ * SCHED_RR:
+ * r:<prio>
+ * R:<prio>
+ * SCHED_FIFO:
+ * f:<prio>
+ * F:<prio>
+ * SCHED_DEADLINE:
+ * d:runtime:period
+ * D:runtime:period
+ */
+int parse_prio(char *arg, struct sched_attr *sched_param)
+{
+ long prio;
+ long runtime;
+ long period;
+
+ memset(sched_param, 0, sizeof(*sched_param));
+ sched_param->size = sizeof(*sched_param);
+
+ switch (arg[0]) {
+ case 'd':
+ case 'D':
+ /* d:runtime:period */
+ if (strlen(arg) < 4)
+ return -1;
+
+ runtime = get_long_ns_after_colon(arg);
+ if (runtime == INVALID_VAL)
+ return -1;
+
+ period = get_long_ns_after_colon(&arg[2]);
+ if (period == INVALID_VAL)
+ return -1;
+
+ if (runtime > period)
+ return -1;
+
+ sched_param->sched_policy = SCHED_DEADLINE;
+ sched_param->sched_runtime = runtime;
+ sched_param->sched_deadline = period;
+ sched_param->sched_period = period;
+ break;
+ case 'f':
+ case 'F':
+ /* f:prio */
+ prio = get_long_after_colon(arg);
+ if (prio == INVALID_VAL)
+ return -1;
+
+ if (prio < sched_get_priority_min(SCHED_FIFO))
+ return -1;
+ if (prio > sched_get_priority_max(SCHED_FIFO))
+ return -1;
+
+ sched_param->sched_policy = SCHED_FIFO;
+ sched_param->sched_priority = prio;
+ break;
+ case 'r':
+ case 'R':
+ /* r:prio */
+ prio = get_long_after_colon(arg);
+ if (prio == INVALID_VAL)
+ return -1;
+
+ if (prio < sched_get_priority_min(SCHED_RR))
+ return -1;
+ if (prio > sched_get_priority_max(SCHED_RR))
+ return -1;
+
+ sched_param->sched_policy = SCHED_RR;
+ sched_param->sched_priority = prio;
+ break;
+ case 'o':
+ case 'O':
+ /* o:prio */
+ prio = get_long_after_colon(arg);
+ if (prio == INVALID_VAL)
+ return -1;
+
+ if (prio < sched_get_priority_min(SCHED_OTHER))
+ return -1;
+ if (prio > sched_get_priority_max(SCHED_OTHER))
+ return -1;
+
+ sched_param->sched_policy = SCHED_OTHER;
+ sched_param->sched_priority = prio;
+ break;
+ default:
+ return -1;
+ }
+ return 0;
+}
+
+/*
+ * set_cpu_dma_latency - set the /dev/cpu_dma_latecy
+ *
+ * This is used to reduce the exit from idle latency. The value
+ * will be reset once the file descriptor of /dev/cpu_dma_latecy
+ * is closed.
+ *
+ * Return: the /dev/cpu_dma_latecy file descriptor
+ */
+int set_cpu_dma_latency(int32_t latency)
+{
+ int retval;
+ int fd;
+
+ fd = open("/dev/cpu_dma_latency", O_RDWR);
+ if (fd < 0) {
+ err_msg("Error opening /dev/cpu_dma_latency\n");
+ return -1;
+ }
+
+ retval = write(fd, &latency, 4);
+ if (retval < 1) {
+ err_msg("Error setting /dev/cpu_dma_latency\n");
+ close(fd);
+ return -1;
+ }
+
+ debug_msg("Set /dev/cpu_dma_latency to %d\n", latency);
+
+ return fd;
+}
+
+#define _STR(x) #x
+#define STR(x) _STR(x)
+
+/*
+ * find_mount - find a the mount point of a given fs
+ *
+ * Returns 0 if mount is not found, otherwise return 1 and fill mp
+ * with the mount point.
+ */
+static const int find_mount(const char *fs, char *mp, int sizeof_mp)
+{
+ char mount_point[MAX_PATH];
+ char type[100];
+ int found = 0;
+ FILE *fp;
+
+ fp = fopen("/proc/mounts", "r");
+ if (!fp)
+ return 0;
+
+ while (fscanf(fp, "%*s %" STR(MAX_PATH) "s %99s %*s %*d %*d\n", mount_point, type) == 2) {
+ if (strcmp(type, fs) == 0) {
+ found = 1;
+ break;
+ }
+ }
+ fclose(fp);
+
+ if (!found)
+ return 0;
+
+ memset(mp, 0, sizeof_mp);
+ strncpy(mp, mount_point, sizeof_mp - 1);
+
+ debug_msg("Fs %s found at %s\n", fs, mp);
+ return 1;
+}
+
+/*
+ * get_self_cgroup - get the current thread cgroup path
+ *
+ * Parse /proc/$$/cgroup file to get the thread's cgroup. As an example of line to parse:
+ *
+ * 0::/user.slice/user-0.slice/session-3.scope'\n'
+ *
+ * This function is interested in the content after the second : and before the '\n'.
+ *
+ * Returns 1 if a string was found, 0 otherwise.
+ */
+static int get_self_cgroup(char *self_cg, int sizeof_self_cg)
+{
+ char path[MAX_PATH], *start;
+ int fd, retval;
+
+ snprintf(path, MAX_PATH, "/proc/%d/cgroup", getpid());
+
+ fd = open(path, O_RDONLY);
+ if (fd < 0)
+ return 0;
+
+ retval = read(fd, path, MAX_PATH);
+
+ close(fd);
+
+ if (retval <= 0)
+ return 0;
+
+ start = path;
+
+ start = strstr(start, ":");
+ if (!start)
+ return 0;
+
+ /* skip ":" */
+ start++;
+
+ start = strstr(start, ":");
+ if (!start)
+ return 0;
+
+ /* skip ":" */
+ start++;
+
+ if (strlen(start) >= sizeof_self_cg)
+ return 0;
+
+ snprintf(self_cg, sizeof_self_cg, "%s", start);
+
+ /* Swap '\n' with '\0' */
+ start = strstr(self_cg, "\n");
+
+ /* there must be '\n' */
+ if (!start)
+ return 0;
+
+ /* ok, it found a string after the second : and before the \n */
+ *start = '\0';
+
+ return 1;
+}
+
+/*
+ * set_comm_cgroup - Set cgroup to pid_t pid
+ *
+ * If cgroup argument is not NULL, the threads will move to the given cgroup.
+ * Otherwise, the cgroup of the calling, i.e., rtla, thread will be used.
+ *
+ * Supports cgroup v2.
+ *
+ * Returns 1 on success, 0 otherwise.
+ */
+int set_pid_cgroup(pid_t pid, const char *cgroup)
+{
+ char cgroup_path[MAX_PATH - strlen("/cgroup.procs")];
+ char cgroup_procs[MAX_PATH];
+ char pid_str[24];
+ int retval;
+ int cg_fd;
+
+ retval = find_mount("cgroup2", cgroup_path, sizeof(cgroup_path));
+ if (!retval) {
+ err_msg("Did not find cgroupv2 mount point\n");
+ return 0;
+ }
+
+ if (!cgroup) {
+ retval = get_self_cgroup(&cgroup_path[strlen(cgroup_path)],
+ sizeof(cgroup_path) - strlen(cgroup_path));
+ if (!retval) {
+ err_msg("Did not find self cgroup\n");
+ return 0;
+ }
+ } else {
+ snprintf(&cgroup_path[strlen(cgroup_path)],
+ sizeof(cgroup_path) - strlen(cgroup_path), "%s/", cgroup);
+ }
+
+ snprintf(cgroup_procs, MAX_PATH, "%s/cgroup.procs", cgroup_path);
+
+ debug_msg("Using cgroup path at: %s\n", cgroup_procs);
+
+ cg_fd = open(cgroup_procs, O_RDWR);
+ if (cg_fd < 0)
+ return 0;
+
+ snprintf(pid_str, sizeof(pid_str), "%d\n", pid);
+
+ retval = write(cg_fd, pid_str, strlen(pid_str));
+ if (retval < 0)
+ err_msg("Error setting cgroup attributes for pid:%s - %s\n",
+ pid_str, strerror(errno));
+ else
+ debug_msg("Set cgroup attributes for pid:%s\n", pid_str);
+
+ close(cg_fd);
+
+ return (retval >= 0);
+}
+
+/**
+ * set_comm_cgroup - Set cgroup to threads starting with char *comm_prefix
+ *
+ * If cgroup argument is not NULL, the threads will move to the given cgroup.
+ * Otherwise, the cgroup of the calling, i.e., rtla, thread will be used.
+ *
+ * Supports cgroup v2.
+ *
+ * Returns 1 on success, 0 otherwise.
+ */
+int set_comm_cgroup(const char *comm_prefix, const char *cgroup)
+{
+ char cgroup_path[MAX_PATH - strlen("/cgroup.procs")];
+ char cgroup_procs[MAX_PATH];
+ struct dirent *proc_entry;
+ DIR *procfs;
+ int retval;
+ int cg_fd;
+
+ if (strlen(comm_prefix) >= MAX_PATH) {
+ err_msg("Command prefix is too long: %d < strlen(%s)\n",
+ MAX_PATH, comm_prefix);
+ return 0;
+ }
+
+ retval = find_mount("cgroup2", cgroup_path, sizeof(cgroup_path));
+ if (!retval) {
+ err_msg("Did not find cgroupv2 mount point\n");
+ return 0;
+ }
+
+ if (!cgroup) {
+ retval = get_self_cgroup(&cgroup_path[strlen(cgroup_path)],
+ sizeof(cgroup_path) - strlen(cgroup_path));
+ if (!retval) {
+ err_msg("Did not find self cgroup\n");
+ return 0;
+ }
+ } else {
+ snprintf(&cgroup_path[strlen(cgroup_path)],
+ sizeof(cgroup_path) - strlen(cgroup_path), "%s/", cgroup);
+ }
+
+ snprintf(cgroup_procs, MAX_PATH, "%s/cgroup.procs", cgroup_path);
+
+ debug_msg("Using cgroup path at: %s\n", cgroup_procs);
+
+ cg_fd = open(cgroup_procs, O_RDWR);
+ if (cg_fd < 0)
+ return 0;
+
+ procfs = opendir("/proc");
+ if (!procfs) {
+ err_msg("Could not open procfs\n");
+ goto out_cg;
+ }
+
+ while ((proc_entry = readdir(procfs))) {
+
+ retval = procfs_is_workload_pid(comm_prefix, proc_entry);
+ if (!retval)
+ continue;
+
+ retval = write(cg_fd, proc_entry->d_name, strlen(proc_entry->d_name));
+ if (retval < 0) {
+ err_msg("Error setting cgroup attributes for pid:%s - %s\n",
+ proc_entry->d_name, strerror(errno));
+ goto out_procfs;
+ }
+
+ debug_msg("Set cgroup attributes for pid:%s\n", proc_entry->d_name);
+ }
+
+ closedir(procfs);
+ close(cg_fd);
+ return 1;
+
+out_procfs:
+ closedir(procfs);
+out_cg:
+ close(cg_fd);
+ return 0;
+}
+
+/**
+ * auto_house_keeping - Automatically move rtla out of measurement threads
+ *
+ * Try to move rtla away from the tracer, if possible.
+ *
+ * Returns 1 on success, 0 otherwise.
+ */
+int auto_house_keeping(cpu_set_t *monitored_cpus)
+{
+ cpu_set_t rtla_cpus, house_keeping_cpus;
+ int retval;
+
+ /* first get the CPUs in which rtla can actually run. */
+ retval = sched_getaffinity(getpid(), sizeof(rtla_cpus), &rtla_cpus);
+ if (retval == -1) {
+ debug_msg("Could not get rtla affinity, rtla might run with the threads!\n");
+ return 0;
+ }
+
+ /* then check if the existing setup is already good. */
+ CPU_AND(&house_keeping_cpus, &rtla_cpus, monitored_cpus);
+ if (!CPU_COUNT(&house_keeping_cpus)) {
+ debug_msg("rtla and the monitored CPUs do not share CPUs.");
+ debug_msg("Skipping auto house-keeping\n");
+ return 1;
+ }
+
+ /* remove the intersection */
+ CPU_XOR(&house_keeping_cpus, &rtla_cpus, monitored_cpus);
+
+ /* get only those that rtla can run */
+ CPU_AND(&house_keeping_cpus, &house_keeping_cpus, &rtla_cpus);
+
+ /* is there any cpu left? */
+ if (!CPU_COUNT(&house_keeping_cpus)) {
+ debug_msg("Could not find any CPU for auto house-keeping\n");
+ return 0;
+ }
+
+ retval = sched_setaffinity(getpid(), sizeof(house_keeping_cpus), &house_keeping_cpus);
+ if (retval == -1) {
+ debug_msg("Could not set affinity for auto house-keeping\n");
+ return 0;
+ }
+
+ debug_msg("rtla automatically moved to an auto house-keeping cpu set\n");
+
+ return 1;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-02 23:53:49 +0000