如何擴展C程序以獲得所有內核的CPU使用率

Question

我有一個程序可以計算所有內核的平均CPU使用率。我想擴展該程序以單獨獲取所有內核的CPU使用情況。我無法弄清楚如何爲每個核心單獨做到這一點。 謝謝。

的/ proc/STAT開始是這樣的：

cpu 3698413 14728645 5722454 10134230 69449 0 1223 0 0 0 
cpu0 976719 3443648 1547164 2603386 19834 0 411 0 0 0 
cpu1 919933 3875010 1438785 2355286 17272 0 373 0 0 0 
cpu2 989581 3082865 1559116 2922304 18621 0 169 0 0 0 
cpu3 812180 4327122 1177389 2253254 13722 0 270 0 0 0 

我的計劃，calcutates平均：

#include <stdlib.h> 
#include <stdio.h> 
#include <stdarg.h> 
#include <unistd.h> 

#define PROCSTATFILE "/proc/stat" 

void eprintf(const char *fmt, ...) { 
    va_list ap; 
    va_start(ap, fmt); 
    vfprintf(stderr, fmt, ap); 
    va_end(ap); 
    exit(EXIT_FAILURE); 
} 

double cpuusage(void) { 
    char buf[BUFSIZ]; 
    static unsigned long long lastuser, lastnice, lastsystem, lastidle; 
    unsigned long long user, nice, system, idle; 
    unsigned long long total; 
    double percent; 
    FILE *fp; 

    if (lastuser && lastnice && lastsystem && lastidle) { 
     fp = fopen(PROCSTATFILE, "r"); 
     if (!fp) 
      eprintf("failed to open %s\n", PROCSTATFILE); 
     fgets(buf, BUFSIZ, fp); 
     sscanf(buf, "cpu %llu %llu %llu %llu", &user, &nice, &system, &idle); 
     fclose(fp); 

     percent = 0; 
     total = 0; 
     total += (user - lastuser); 
     total += (nice - lastnice); 
     total += (system - lastsystem); 
     percent = total; 
     total += (idle - lastidle); 
     percent /= total; 
     percent *= 100; 
    } 

    fp = fopen(PROCSTATFILE, "r"); 
    if (!fp) 
     eprintf("failed to open %s\n", PROCSTATFILE); 
    fgets(buf, BUFSIZ, fp); 
    sscanf(buf, "cpu %llu %llu %llu %llu", &lastuser, &lastnice, &lastsystem, &lastidle); 
    fclose(fp); 

    return percent; 
} 

int main(void) { 
    while (1) { 
     printf("cpu usage:%f\n", cpuusage()); 
     sleep(1); 
    } 

    return EXIT_SUCCESS; 
} 

Answer 1

這裏是解決方案：

#include <stdlib.h> 
#include <stdio.h> 
#include <stdarg.h> 
#include <string.h> 
#include <unistd.h> 
#include <sys/types.h> 
#include <sys/sysinfo.h> 

#define PROCSTATFILE "/proc/stat" 

void eprintf(const char *fmt, ...) { 
    va_list ap; 
    va_start(ap, fmt); 
    vfprintf(stderr, fmt, ap); 
    va_end(ap); 
    exit(EXIT_FAILURE); 
} 

void *emalloc(size_t size) { 
    void *p; 

    p = malloc(size); 
    if (!p) 
     eprintf("out of memory\n"); 
    return p; 
} 

int cpucount(void) { 
    int i; 
    FILE *fp; 
    char buf[BUFSIZ]; 

    fp = fopen(PROCSTATFILE, "r"); 
    if (!fp) 
     eprintf("can't open %s\n", PROCSTATFILE); 
    fgets(buf, BUFSIZ, fp); 
    for (i = 0; fgets(buf, BUFSIZ, fp); i++) 
     if (!!strncmp("cpu", buf, 3)) 
      break; 

    fclose(fp); 

    return i; 
} 

double *cpuusage(void) { 
    int i; 
    char buf[BUFSIZ]; 
    int cpus; 
    int cpuid; 
    int r; 
    static unsigned long long *lastuser, *lastnice, *lastsystem, *lastidle; 
    unsigned long long *user, *nice, *system, *idle; 
    unsigned long long total; 
    static double *percent; 
    FILE *fp; 

    cpus = cpucount(); 

    if (!lastuser) 
     lastuser = emalloc(cpus * sizeof(long long)); 
    if (!lastnice) 
     lastnice = emalloc(cpus * sizeof(long long)); 
    if (!lastsystem) 
     lastsystem = emalloc(cpus * sizeof(long long)); 
    if (!lastidle) 
     lastidle = emalloc(cpus * sizeof(long long)); 

    user = emalloc(cpus * sizeof(long long)); 
    nice = emalloc(cpus * sizeof(long long)); 
    system = emalloc(cpus * sizeof(long long)); 
    idle = emalloc(cpus * sizeof(long long)); 

    if (!percent) 
     percent = calloc((cpus + 1), sizeof(double)); 

    fp = fopen(PROCSTATFILE, "r"); 
    if (!fp) 
     eprintf("can't open %s\n", PROCSTATFILE); 
    fgets(buf, BUFSIZ, fp); 
    for (i = 0; i < cpus; i++) { 
     if (lastuser[i] && lastnice[i] && lastsystem[i] && lastidle[i]) { 
      fgets(buf, BUFSIZ, fp); 
      r = sscanf(buf, "cpu%d %llu %llu %llu %llu", 
        &cpuid, &user[i], &nice[i], &system[i], &idle[i]); 
      if (r < 5) 
       break; 

      percent[i] = i; 
      total = i; 
      total += (user[i] - lastuser[i]); 
      total += (nice[i] - lastnice[i]); 
      total += (system[i] - lastsystem[i]); 
      percent[i] = total; 
      total += (idle[i] - lastidle[i]); 
      percent[i] /= total; 
      percent[i] *= 100; 
     } 
    } 
    free(user); 
    free(nice); 
    free(system); 
    free(idle); 
    fclose(fp); 

    fp = fopen(PROCSTATFILE, "r"); 
    if (!fp) 
     eprintf("can't open %s\n", PROCSTATFILE); 
    fgets(buf, BUFSIZ, fp); 
    for (i = 0; i < 4; i++) { 
     fgets(buf, BUFSIZ, fp); 
     r = sscanf(buf, "cpu%d %llu %llu %llu %llu", 
       &cpuid, &lastuser[i], &lastnice[i], &lastsystem[i], &lastidle[i]); 
     if (r < 5) 
      break; 
    } 
    fclose(fp); 

    return percent; 
} 

int main(void) { 
    int i; 
    double *percent; 

    while (1) { 
     percent = cpuusage(); 

     for (i = 0; percent[i]; i++) 
      printf("cpu%d:%.2f%%\n", i, percent[i]); 
     sleep(1); 
    } 

    return EXIT_SUCCESS; 
}