124 lines
2.8 KiB
C
124 lines
2.8 KiB
C
/*
|
|
* cpu_governor_monitor - Simple CLI tool to sample the current CPU governor
|
|
* and log it together with a caller-supplied C-state indicator.
|
|
*/
|
|
|
|
#include <errno.h>
|
|
#include <limits.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include <time.h>
|
|
|
|
#define GOVERNOR_PATH "/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor"
|
|
|
|
struct cpu_log_entry {
|
|
char governor[30];
|
|
int c_state;
|
|
time_t timestamp;
|
|
};
|
|
|
|
static void trim_newline(char *str)
|
|
{
|
|
if (!str) {
|
|
return;
|
|
}
|
|
size_t len = strcspn(str, "\r\n");
|
|
str[len] = '\0';
|
|
}
|
|
|
|
const char *get_current_governor(void)
|
|
{
|
|
static char governor_buf[30] = "unknown";
|
|
FILE *file = fopen(GOVERNOR_PATH, "r");
|
|
|
|
if (!file) {
|
|
perror("fopen scaling_governor");
|
|
return governor_buf;
|
|
}
|
|
|
|
if (!fgets(governor_buf, sizeof(governor_buf), file)) {
|
|
perror("fgets scaling_governor");
|
|
snprintf(governor_buf, sizeof(governor_buf), "unknown");
|
|
fclose(file);
|
|
return governor_buf;
|
|
}
|
|
|
|
fclose(file);
|
|
trim_newline(governor_buf);
|
|
return governor_buf;
|
|
}
|
|
|
|
void log_cpu_state(const char *governor, int c_state)
|
|
{
|
|
struct cpu_log_entry entry;
|
|
memset(&entry, 0, sizeof(entry));
|
|
|
|
if (governor) {
|
|
strncpy(entry.governor, governor, sizeof(entry.governor) - 1);
|
|
} else {
|
|
strncpy(entry.governor, "unknown", sizeof(entry.governor) - 1);
|
|
}
|
|
|
|
entry.c_state = c_state;
|
|
entry.timestamp = time(NULL);
|
|
|
|
char ts_buf[32];
|
|
struct tm tm_info;
|
|
|
|
if (localtime_r(&entry.timestamp, &tm_info) != NULL) {
|
|
strftime(ts_buf, sizeof(ts_buf), "%Y-%m-%d %H:%M:%S", &tm_info);
|
|
} else {
|
|
snprintf(ts_buf, sizeof(ts_buf), "unknown_time");
|
|
}
|
|
|
|
printf("timestamp=%s (epoch=%ld) governor=%s c_state=%d\n",
|
|
ts_buf,
|
|
(long)entry.timestamp,
|
|
entry.governor,
|
|
entry.c_state);
|
|
}
|
|
|
|
static void print_usage(const char *prog)
|
|
{
|
|
fprintf(stderr, "Usage: %s [c_state]\n", prog);
|
|
fprintf(stderr, "If c_state is omitted, -1 is logged to indicate unknown.\n");
|
|
}
|
|
|
|
static int parse_c_state(const char *arg, int *c_state)
|
|
{
|
|
char *endptr = NULL;
|
|
long value = strtol(arg, &endptr, 10);
|
|
|
|
if (endptr == arg || *endptr != '\0') {
|
|
return -1;
|
|
}
|
|
|
|
if (value < INT_MIN || value > INT_MAX) {
|
|
return -1;
|
|
}
|
|
|
|
*c_state = (int)value;
|
|
return 0;
|
|
}
|
|
|
|
int main(int argc, char *argv[])
|
|
{
|
|
int c_state = -1;
|
|
|
|
if (argc > 2) {
|
|
print_usage(argv[0]);
|
|
return EXIT_FAILURE;
|
|
}
|
|
|
|
if (argc == 2) {
|
|
if (parse_c_state(argv[1], &c_state) != 0) {
|
|
fprintf(stderr, "Invalid c_state value: %s\n", argv[1]);
|
|
return EXIT_FAILURE;
|
|
}
|
|
}
|
|
|
|
const char *governor = get_current_governor();
|
|
log_cpu_state(governor, c_state);
|
|
return EXIT_SUCCESS;
|
|
}
|