252 lines · c
1// SPDX-License-Identifier: GPL-2.02 3#define _GNU_SOURCE4#include <errno.h>5#include <stdio.h>6#include <stdlib.h>7#include <signal.h>8#include <sched.h>9#include <string.h>10#include <unistd.h>11#include <fcntl.h>12#include <locale.h>13#include <sys/types.h>14#include <sys/stat.h>15#include <sys/time.h>16#include <sys/wait.h>17 18#include <bpf/bpf.h>19#include <bpf/libbpf.h>20 21static int cstate_map_fd, pstate_map_fd;22 23#define MAX_CPU 824#define MAX_PSTATE_ENTRIES 525#define MAX_CSTATE_ENTRIES 326#define MAX_STARS 4027 28#define CPUFREQ_MAX_SYSFS_PATH "/sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq"29#define CPUFREQ_LOWEST_FREQ "208000"30#define CPUFREQ_HIGHEST_FREQ "12000000"31 32struct cpu_stat_data {33 unsigned long cstate[MAX_CSTATE_ENTRIES];34 unsigned long pstate[MAX_PSTATE_ENTRIES];35};36 37static struct cpu_stat_data stat_data[MAX_CPU];38 39static void cpu_stat_print(void)40{41 int i, j;42 char state_str[sizeof("cstate-9")];43 struct cpu_stat_data *data;44 45 /* Clear screen */46 printf("\033[2J");47 48 /* Header */49 printf("\nCPU states statistics:\n");50 printf("%-10s ", "state(ms)");51 52 for (i = 0; i < MAX_CSTATE_ENTRIES; i++) {53 sprintf(state_str, "cstate-%d", i);54 printf("%-11s ", state_str);55 }56 57 for (i = 0; i < MAX_PSTATE_ENTRIES; i++) {58 sprintf(state_str, "pstate-%d", i);59 printf("%-11s ", state_str);60 }61 62 printf("\n");63 64 for (j = 0; j < MAX_CPU; j++) {65 data = &stat_data[j];66 67 printf("CPU-%-6d ", j);68 for (i = 0; i < MAX_CSTATE_ENTRIES; i++)69 printf("%-11lu ", data->cstate[i] / 1000000);70 71 for (i = 0; i < MAX_PSTATE_ENTRIES; i++)72 printf("%-11lu ", data->pstate[i] / 1000000);73 74 printf("\n");75 }76}77 78static void cpu_stat_update(int cstate_fd, int pstate_fd)79{80 unsigned long key, value;81 int c, i;82 83 for (c = 0; c < MAX_CPU; c++) {84 for (i = 0; i < MAX_CSTATE_ENTRIES; i++) {85 key = c * MAX_CSTATE_ENTRIES + i;86 bpf_map_lookup_elem(cstate_fd, &key, &value);87 stat_data[c].cstate[i] = value;88 }89 90 for (i = 0; i < MAX_PSTATE_ENTRIES; i++) {91 key = c * MAX_PSTATE_ENTRIES + i;92 bpf_map_lookup_elem(pstate_fd, &key, &value);93 stat_data[c].pstate[i] = value;94 }95 }96}97 98/*99 * This function is copied from 'idlestat' tool function100 * idlestat_wake_all() in idlestate.c.101 *102 * It sets the self running task affinity to cpus one by one so can wake up103 * the specific CPU to handle scheduling; this results in all cpus can be104 * waken up once and produce ftrace event 'trace_cpu_idle'.105 */106static int cpu_stat_inject_cpu_idle_event(void)107{108 int rcpu, i, ret;109 cpu_set_t cpumask;110 cpu_set_t original_cpumask;111 112 ret = sysconf(_SC_NPROCESSORS_CONF);113 if (ret < 0)114 return -1;115 116 rcpu = sched_getcpu();117 if (rcpu < 0)118 return -1;119 120 /* Keep track of the CPUs we will run on */121 sched_getaffinity(0, sizeof(original_cpumask), &original_cpumask);122 123 for (i = 0; i < ret; i++) {124 125 /* Pointless to wake up ourself */126 if (i == rcpu)127 continue;128 129 /* Pointless to wake CPUs we will not run on */130 if (!CPU_ISSET(i, &original_cpumask))131 continue;132 133 CPU_ZERO(&cpumask);134 CPU_SET(i, &cpumask);135 136 sched_setaffinity(0, sizeof(cpumask), &cpumask);137 }138 139 /* Enable all the CPUs of the original mask */140 sched_setaffinity(0, sizeof(original_cpumask), &original_cpumask);141 return 0;142}143 144/*145 * It's possible to have no any frequency change for long time and cannot146 * get ftrace event 'trace_cpu_frequency' for long period, this introduces147 * big deviation for pstate statistics.148 *149 * To solve this issue, below code forces to set 'scaling_max_freq' to 208MHz150 * for triggering ftrace event 'trace_cpu_frequency' and then recovery back to151 * the maximum frequency value 1.2GHz.152 */153static int cpu_stat_inject_cpu_frequency_event(void)154{155 int len, fd;156 157 fd = open(CPUFREQ_MAX_SYSFS_PATH, O_WRONLY);158 if (fd < 0) {159 printf("failed to open scaling_max_freq, errno=%d\n", errno);160 return fd;161 }162 163 len = write(fd, CPUFREQ_LOWEST_FREQ, strlen(CPUFREQ_LOWEST_FREQ));164 if (len < 0) {165 printf("failed to open scaling_max_freq, errno=%d\n", errno);166 goto err;167 }168 169 len = write(fd, CPUFREQ_HIGHEST_FREQ, strlen(CPUFREQ_HIGHEST_FREQ));170 if (len < 0) {171 printf("failed to open scaling_max_freq, errno=%d\n", errno);172 goto err;173 }174 175err:176 close(fd);177 return len;178}179 180static void int_exit(int sig)181{182 cpu_stat_inject_cpu_idle_event();183 cpu_stat_inject_cpu_frequency_event();184 cpu_stat_update(cstate_map_fd, pstate_map_fd);185 cpu_stat_print();186 exit(0);187}188 189int main(int argc, char **argv)190{191 struct bpf_link *link = NULL;192 struct bpf_program *prog;193 struct bpf_object *obj;194 char filename[256];195 int ret;196 197 snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);198 obj = bpf_object__open_file(filename, NULL);199 if (libbpf_get_error(obj)) {200 fprintf(stderr, "ERROR: opening BPF object file failed\n");201 return 0;202 }203 204 prog = bpf_object__find_program_by_name(obj, "bpf_prog1");205 if (!prog) {206 printf("finding a prog in obj file failed\n");207 goto cleanup;208 }209 210 /* load BPF program */211 if (bpf_object__load(obj)) {212 fprintf(stderr, "ERROR: loading BPF object file failed\n");213 goto cleanup;214 }215 216 cstate_map_fd = bpf_object__find_map_fd_by_name(obj, "cstate_duration");217 pstate_map_fd = bpf_object__find_map_fd_by_name(obj, "pstate_duration");218 if (cstate_map_fd < 0 || pstate_map_fd < 0) {219 fprintf(stderr, "ERROR: finding a map in obj file failed\n");220 goto cleanup;221 }222 223 link = bpf_program__attach(prog);224 if (libbpf_get_error(link)) {225 fprintf(stderr, "ERROR: bpf_program__attach failed\n");226 link = NULL;227 goto cleanup;228 }229 230 ret = cpu_stat_inject_cpu_idle_event();231 if (ret < 0)232 return 1;233 234 ret = cpu_stat_inject_cpu_frequency_event();235 if (ret < 0)236 return 1;237 238 signal(SIGINT, int_exit);239 signal(SIGTERM, int_exit);240 241 while (1) {242 cpu_stat_update(cstate_map_fd, pstate_map_fd);243 cpu_stat_print();244 sleep(5);245 }246 247cleanup:248 bpf_link__destroy(link);249 bpf_object__close(obj);250 return 0;251}252