Linux displays the time-consuming, number of calls, and calling relationship of each function call

 

[root@shanghai c++11]# cat test3.c
#include <stdio.h>
int a(void) {
    int i=0,g=0;
    while(i++<200000)
    {
        g^=i;
    }
    return g;
}
int b(void) {
    int i=0,g=0;
    while(i++<800000)
    {
        g^=i;
    }
    return g;
}
int main(int argc, char** argv)
{
    int iterations;
    if(argc != 2)
    {
        printf("Usage %s <请输入一个整数>\n", argv[0]);
        return -1;
    }
    else
        iterations = atoi(argv[1]);
    printf("你键入的数是 = %d\n", iterations);
    while(iterations--)
    {
        a();
        b();
    }
}
[root@shanghai c++11]# 


	
[root@shanghai c++11]# gcc -g -pg test3.c && ./a.out 9999
你键入的数是 = 9999
[root@shanghai c++11]# 

[root@shanghai c++11]# ll
total 64
-rwxr-xr-x 1 root root 10176 Mar 22 16:33 a.out
-rw-r--r-- 1 root root   471 Mar 22 16:34 gmon.out
-rw-r--r-- 1 root root   537 Mar 22 16:33 test3.c
[root@shanghai c++11]# 
[root@shanghai c++11]# gprof a.out gmon.out > log

Each sample counts as 0.01 seconds.
  %   cumulative   self              self     total           
 time   seconds   seconds    calls  ms/call  ms/call  name    
 81.22     21.19    21.19     9999     2.12     2.12  b
 19.88     26.38     5.19     9999     0.52     0.52  a
 
 
index % time    self  children    called     name
                                                 <spontaneous>
[1]    100.0    0.00   26.38                 main [1]
               21.19    0.00    9999/9999        b [2]
                5.19    0.00    9999/9999        a [3]
-----------------------------------------------
               21.19    0.00    9999/9999        main [1]
[2]     80.3   21.19    0.00    9999         b [2]
-----------------------------------------------
                5.19    0.00    9999/9999        main [1]
[3]     19.7    5.19    0.00    9999         a [3]
-----------------------------------------------