获取cpu频率的代码

taskset是linux自带的一个命令，可用来将进程绑定到指定CPU
相关的函数有: sched_setaffinity, CPU_CLR, CPU_ISSET, CPU_SET, CPU_ZERO

1. // cpufreq库可在/usr/lib目录下找到
   
2. // 编译: g++ -g -o x x.cpp -lcpufreq
   
3. // 需要以root用户执行以下代码
   
4. //#include <cpufreq.h>
   
5. #include <stdio.h>
   
6. #include <sys/sysinfo.h> // get_nprocs
   
7. 
   
8. // 如果不存在/usr/include/cpufreq.h
   
9. #ifndef _CPUFREQ_H
   
10.     extern "C" int cpufreq_cpu_exists(unsigned int cpu);
    
11.     extern "C" unsigned long cpufreq_get_freq_kernel(unsigned int cpu);
    
12.     extern "C" unsigned long cpufreq_get_freq_hardware(unsigned int cpu);
    
13.     extern "C" int cpufreq_get_hardware_limits(unsigned int cpu, unsigned long *min, unsigned long *max);
    
14. #endif
    
15. 
    
16. int main()
    
17. {
    
18.     // 取得cpu core的个数，proc是processor的意思
    
19.     int nprocs = get_nprocs();
    
20.     for (int i=0; i<nprocs; ++i)
    
21.     {
    
22.         if (0 == cpufreq_cpu_exists(i))
    
23.         {
    
24.             unsigned long min_freq = 0;
    
25.             unsigned long max_freq = 0;
    
26.             cpufreq_get_hardware_limits(i, &min_freq, &max_freq);
    
27. 
    
28.             printf("cpu[%d]:\n", i);
    
29.             printf("min_freq: %lu, max_freq: %lu\n", min_freq, max_freq);
    
30.             printf("kernel freq: %lu, hardware freq: %lu\n", cpufreq_get_freq_kernel(i), cpufreq_get_freq_hardware(i));
    
31.             printf("\n");
    
32.         }
    
33.     }
    
34. 
    
35.     return 0;
    
36. }