// SPDX-License-Identifier: GPL-2.0
#define _GNU_SOURCE
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <sched.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <locale.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <bpf/bpf.h>
#include <bpf/libbpf.h>
static int cstate_map_fd, pstate_map_fd;
#define MAX_CPU 8
#define MAX_PSTATE_ENTRIES 5
#define MAX_CSTATE_ENTRIES 3
#define MAX_STARS 40
#define CPUFREQ_MAX_SYSFS_PATH "/sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq"
#define CPUFREQ_LOWEST_FREQ "208000"
#define CPUFREQ_HIGHEST_FREQ "12000000"
struct cpu_stat_data {
unsigned long cstate[MAX_CSTATE_ENTRIES];
unsigned long pstate[MAX_PSTATE_ENTRIES];
};
static struct cpu_stat_data stat_data[MAX_CPU];
static void cpu_stat_print(void)
{
int i, j;
char state_str[sizeof("cstate-9")];
struct cpu_stat_data *data;
/* Clear screen */
printf("\033[2J");
/* Header */
printf("\nCPU states statistics:\n");
printf("%-10s ", "state(ms)");
for (i = 0; i < MAX_CSTATE_ENTRIES; i++) {
sprintf(state_str, "cstate-%d", i);
printf("%-11s ", state_str);
}
for (i = 0; i < MAX_PSTATE_ENTRIES; i++) {
sprintf(state_str, "pstate-%d", i);
printf("%-11s ", state_str);
}
printf("\n");
for (j = 0; j < MAX_CPU; j++) {
data = &stat_data[j];
printf("CPU-%-6d ", j);
for (i = 0; i < MAX_CSTATE_ENTRIES; i++)
printf("%-11lu ", data->cstate[i] / 1000000);
for (i = 0; i < MAX_PSTATE_ENTRIES; i++)
printf("%-11lu ", data->pstate[i] / 1000000);
printf("\n");
}
}
static void cpu_stat_update(int cstate_fd, int pstate_fd)
{
unsigned long key, value;
int c, i;
for (c = 0; c < MAX_CPU; c++) {
for (i = 0; i < MAX_CSTATE_ENTRIES; i++) {
key = c * MAX_CSTATE_ENTRIES + i;
bpf_map_lookup_elem(cstate_fd, &key, &value);
stat_data[c].cstate[i] = value;
}
for (i = 0; i < MAX_PSTATE_ENTRIES; i++) {
key = c * MAX_PSTATE_ENTRIES + i;
bpf_map_lookup_elem(pstate_fd, &key, &value);
stat_data[c].pstate[i] = value;
}
}
}
/*
* This function is copied from 'idlestat' tool function
* idlestat_wake_all() in idlestate.c.
*
* It sets the self running task affinity to cpus one by one so can wake up
* the specific CPU to handle scheduling; this results in all cpus can be
* waken up once and produce ftrace event 'trace_cpu_idle'.
*/
static int cpu_stat_inject_cpu_idle_event(void)
{
int rcpu, i, ret;
cpu_set_t cpumask;
cpu_set_t original_cpumask;
ret = sysconf(_SC_NPROCESSORS_CONF);
if (ret < 0)
return -1;
rcpu = sched_getcpu();
if (rcpu < 0)
return -1;
/* Keep track of the CPUs we will run on */
sched_getaffinity(0, sizeof(original_cpumask), &original_cpumask);
for (i = 0; i < ret; i++) {
/* Pointless to wake up ourself */
if (i == rcpu)
continue;
/* Pointless to wake CPUs we will not run on */
if (!CPU_ISSET(i, &original_cpumask))
continue;
CPU_ZERO(&cpumask);
CPU_SET(i, &cpumask);
sched_setaffinity(0, sizeof(cpumask), &cpumask);
}
/* Enable all the CPUs of the original mask */
sched_setaffinity(0, sizeof(original_cpumask), &original_cpumask);
return 0;
}
/*
* It's possible to have no any frequency change for long time and cannot
* get ftrace event 'trace_cpu_frequency' for long period, this introduces
* big deviation for pstate statistics.
*
* To solve this issue, below code forces to set 'scaling_max_freq' to 208MHz
* for triggering ftrace event 'trace_cpu_frequency' and then recovery back to
* the maximum frequency value 1.2GHz.
*/
static int cpu_stat_inject_cpu_frequency_event(void)
{
int len, fd;
fd = open(CPUFREQ_MAX_SYSFS_PATH, O_WRONLY);
if (fd < 0) {
printf("failed to open scaling_max_freq, errno=%d\n", errno);
return fd;
}
len = write(fd, CPUFREQ_LOWEST_FREQ, strlen(CPUFREQ_LOWEST_FREQ));
if (len < 0) {
printf("failed to open scaling_max_freq, errno=%d\n", errno);
goto err;
}
len = write(fd, CPUFREQ_HIGHEST_FREQ, strlen(CPUFREQ_HIGHEST_FREQ));
if (len < 0) {
printf("failed to open scaling_max_freq, errno=%d\n", errno);
goto err;
}
err:
close(fd);
return len;
}
static void int_exit(int sig)
{
cpu_stat_inject_cpu_idle_event();
cpu_stat_inject_cpu_frequency_event();
cpu_stat_update(cstate_map_fd, pstate_map_fd);
cpu_stat_print();
exit(0);
}
int main(int argc, char **argv)
{
struct bpf_link *link = NULL;
struct bpf_program *prog;
struct bpf_object *obj;
char filename[256];
int ret;
snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
obj = bpf_object__open_file(filename, NULL);
if (libbpf_get_error(obj)) {
fprintf(stderr, "ERROR: opening BPF object file failed\n");
return 0;
}
prog = bpf_object__find_program_by_name(obj, "bpf_prog1");
if (!prog) {
printf("finding a prog in obj file failed\n");
goto cleanup;
}
/* load BPF program */
if (bpf_object__load(obj)) {
fprintf(stderr, "ERROR: loading BPF object file failed\n");
goto cleanup;
}
cstate_map_fd = bpf_object__find_map_fd_by_name(obj, "cstate_duration");
pstate_map_fd = bpf_object__find_map_fd_by_name(obj, "pstate_duration");
if (cstate_map_fd < 0 || pstate_map_fd < 0) {
fprintf(stderr, "ERROR: finding a map in obj file failed\n");
goto cleanup;
}
link = bpf_program__attach(prog);
if (libbpf_get_error(link)) {
fprintf(stderr, "ERROR: bpf_program__attach failed\n");
link = NULL;
goto cleanup;
}
ret = cpu_stat_inject_cpu_idle_event();
if (ret < 0)
return 1;
ret = cpu_stat_inject_cpu_frequency_event();
if (ret < 0)
return 1;
signal(SIGINT, int_exit);
signal(SIGTERM, int_exit);
while (1) {
cpu_stat_update(cstate_map_fd, pstate_map_fd);
cpu_stat_print();
sleep(5);
}
cleanup:
bpf_link__destroy(link);
bpf_object__close(obj);
return 0;
}
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