c++ - Linux 命令检测程序的计算机资源使用情况

Question

假设有两个程序 a.out 和 b.out 做同样的事情:对元素进行排序。 a.out 实现了一个QuickSort 排序算法，占用O(nlogn) 时间和O(logn) 内存，b.out实现了一个BubbleSort排序算法，耗时O(n^2)，O(1)内存。我想对这两种算法的时间和内存使用情况有一些直观的感受，那么有没有Linux命令可以测量程序运行后的时间和内存使用情况？

Answer 1

以编程方式，我会使用 getrusage() ，它允许您测量单个函数，并且比仅 time 更详细或 top .例如:

#include <sys/time.h>
#include <sys/resource.h>
#include <unistd.h>

int main (int argc, char *argv[])
{
    struct rusage start;
    struct rusage end;

    getrusage (RUSAGE_SELF, &start);    // get time at start

    some_function ();                   // Function to measure

    getrusage (RUSAGE_SELF, &end);      // get time at end

    printf ("System: %d usecs, User: %d usecs\n",
            end.ru_stime.tv_usec - start.ru_stime.tv_usec,
            end.ru_utime.tv_usec - start.ru_utime.tv_usec);
...

rusage结构包含以下内容:

struct rusage {
    struct timeval ru_utime;    // user time used
    struct timeval ru_stime;    // system time used
    long   ru_maxrss;           // maximum resident set size
    long   ru_ixrss;            // integral shared memory size   
    long   ru_idrss;            // integral unshared data size
    long   ru_isrss;            // integral unshared stack size
    long   ru_minflt;           // page reclaims
    long   ru_majflt;           // page faults
    long   ru_nswap;            // swaps
    long   ru_inblock;          // block input operations
    long   ru_oublock;          // block output operations
    long   ru_msgsnd;           // messages sent
    long   ru_msgrcv;           // messages received
    long   ru_nsignals;         // signals received
    long   ru_nvcsw;            // voluntary context switches
    long   ru_nivcsw;           // involuntary context switches
};