linux c 读取cpu多核负载

读取cpu负载信息,get_cpu_real返回多核负载情况，
返回参数：第一个是cpu总负载，后续是各个核心的负载。

/*
*读取cpu负载信息,get_cpu_real返回多核负载情况，
*返回参数：第一个是cpu总负载，后续是各个核心的负载。
*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int get_cpu_real( float *cpu_load );

int main( int argc, char *argv[] )
{
    int i = 0;
    while ( i < 10000 )
    {
        float cpu_f[16];
        get_cpu_real( cpu_f );
        int cpu_all = (int)(100*cpu_f[0]);
        int cpu_i1 = (int)(100*cpu_f[1]);
        fprintf( stdout,"all cpu load=%d, core1= %d\n", cpu_all, cpu_i1  );
        usleep( 1000*500);
    }

    return 0;
}


int get_cpu_load_new( )
{
    char cpu_load[1024] = {0x00};
    int buflen  = sizeof(cpu_load);
    unsigned int total, user, nice, system, idle;

    char cpu[32] = {0x00};
    char text[512] = {0x00};

    FILE *fp;
    fp = fopen("/proc/stat", "r");
    if ( fp == NULL )
        return -1;

    while (fgets(text, 200, fp))
    {
        if (strstr(text, "cpu") == NULL )
            break;

        sscanf(text, "%s %u %u %u %u", cpu, &user, &nice, &system, &idle);
        total = (user + nice + system + idle);

        snprintf(cpu_load+strlen(cpu_load), buflen-strlen(cpu_load),
                "%s %u %u %u %u %u\n",
                cpu, user, nice, system, idle,total);
        memset( text, 0x00, sizeof(text) );
    }
    fclose(fp);

    FILE *fp_cpu = NULL;
    fp_cpu = fopen("/tmp/taw_cpu_load_info", "w+");
    if ( fp_cpu == NULL )
        return -1;
    fwrite( cpu_load, 1, strlen( cpu_load), fp_cpu );
    fclose(fp_cpu);

    return 0;
}

#define TAW_CPU_KERNEL_MAX 16 // 最多支持16核
int get_cpu_real( float *cpu_load )
{
    FILE *fp = NULL;
    char text[512] = {0x00};
    char cpu[32] = {0x00};
    int i = 0;
    unsigned int total_old[TAW_CPU_KERNEL_MAX ] = {0x00};
    unsigned int total_new[TAW_CPU_KERNEL_MAX ] = {0x00};
    unsigned int user_old[TAW_CPU_KERNEL_MAX ] = {0x00};
    unsigned int user_new[TAW_CPU_KERNEL_MAX ] = {0x00};
    unsigned int nice_old[TAW_CPU_KERNEL_MAX ] = {0x00};
    unsigned int nice_new[TAW_CPU_KERNEL_MAX ] = {0x00};
    unsigned int system_old[TAW_CPU_KERNEL_MAX ] = {0x00};
    unsigned int system_new[TAW_CPU_KERNEL_MAX ] = {0x00};
    unsigned int idle_old[TAW_CPU_KERNEL_MAX ] = {0x00};
    unsigned int idle_new[TAW_CPU_KERNEL_MAX ] = {0x00};


    // 读取上次cpu信息
    fp = fopen("/tmp/taw_cpu_load_info", "r");
    i=0;
    while ( fp != NULL && fgets(text, 200, fp) )
    {
        if (strstr(text, "cpu") == NULL )
            break;

        sscanf(text, "%s %u %u %u %u %u", cpu, &user_old[i],
                &nice_old[i], &system_old[i], &idle_old[i], &total_old[i] );
        i++;
    }
    if ( fp != NULL )
        fclose(fp);

    // 读取新的cpu信息
    get_cpu_load_new();
    fp = fopen("/tmp/taw_cpu_load_info", "r");
    if ( fp == NULL )
        return -1;

    i = 0;
    while (fgets(text, 200, fp))
    {
        if (strstr(text, "cpu") == NULL )
            break;

        sscanf(text, "%s %u %u %u %u %u", cpu, &user_new[i], &nice_new[i],
                &system_new[i], &idle_new[i], &total_new[i] );

        if (total_new[i] == total_old[i])
            cpu_load[i] = 0.0f;
        else
        {
            cpu_load[i] = ( (user_new[i] + nice_new[i] + system_new[i] ) -
                    (user_old[i] + nice_old[i] + system_old[i] ) ) / (float)( total_new[i] - total_old[i] );
        }

        i++;
    }
    fclose(fp);

    return 0;
}