c - gprof 中的问题(始终记为零)

Question

我有以下程序

#include<stdio.h>
#include<stdlib.h>
typedef struct struct_node
{
        int data;
        struct struct_node *next;
}node;
typedef node* list;
list st=NULL;
list prev;
list insert(list);
list delete(list);
void display(list);
int n;
main()
{
    int ch;
    while(1)
    {
        printf("MENU\n");
        printf("----\n");
        printf("1.INSERT\n");
        printf("2.DELETE\n");
        printf("3.PRINT\n");
        printf("4.EXIT\n");
        printf("ENTER YOUR CHOICE:");
        scanf("%d",&ch);
        switch(ch)
        {
            case 1:
                st=insert(st);
                printf("NEW NODE INSERTED SUCCESSFULLY\n");
                break;
            case 2:
                st=delete(st);
                printf("\nDELETION SUCCESSFUL.CONTENTS ARE:\n");
                display(st);
                break;
            case 3:
                display(st);
                break;
            case 4:
                exit(0);
            default:
                printf("IT IS INVALID CHOICE\n");
                exit(0);
        }
    }
}   
void display(list temp)
{

    sleep(100);
    printf("THE LINKED LIST\n");
    printf("---------------\n");
    while(temp)
    {
        printf("%d\n",temp->data);
        temp=temp->next;
    }

}
list insert(list temp)
{
    list new;
    int i=0;
    int first=0;
    int ch;
    list prev,current;
    printf("ENTER THE DATA TO INSERT:");
    scanf("%d",&n);
    printf("MENU\n");
    printf("----\n");
    printf("1.INSERT AT FIRST\n");
    printf("2.INSERT AT LAST \n");
    printf("3.INSERT AT THE MIDDLE\n");
    printf("ENTER YOUR CHOICE:");
    scanf("%d",&ch);
    switch(ch)
    {
            case 1:
            new=(list)malloc(sizeof(list));
            new->data=n;    
            new->next=temp;
            st=new;
            return st;
            break;
        case 2:
            st=temp;
            while(temp->next!=NULL)
                temp=temp->next;
            new=(list)malloc(sizeof(list));
            temp->next=new;
            new->data=n;
            new->next=NULL;
            return st;
            break;
        case 3:
            new=(list)malloc(sizeof(list));
                new->data=n;
            st=temp;
            while(temp->next!=NULL)
            {
                ++i;
                prev=temp;
                if(prev->data < n)
                {
                    ++first;
                    current=prev->next;
                    if(current->data > n)
                    {
                        new->next=current;
                        prev->next=new;
                        return st;
                    }
                }
                temp=temp->next;
            }
            if(i==0)
            {
                if(temp->data < n)
                {
                    temp->next=new;
                    new->data=n;
                    new->next=NULL;
                }
                else
                {
                    new->next=temp;
                    temp->next=NULL;
                    st=new;
                }
            }
            else
            {
                if(first==0)
                {
                    new->next=temp;
                    new->data=n;
                    return st;
                }
                temp->next=new;
                new->data=n;
                new->next=NULL;
            }                       
            return st;
            break;
            default:
                printf("INVALID CHOICE\n");
                break;
                }                           
}
list delete(list temp)
{
    int ch;
    int val;
    display(st);
    printf("MENU\n");
    printf("1.DELETE THE FROM FIRST\n");
    printf("2.DELETE FROM LAST NODE\n");
    printf("3.DELETE FROM THE MIDDLE\n");
    printf("ENTER YOUR OPTION:");
    scanf("%d",&ch);
    switch(ch)
    {
        case 1:
            temp=temp->next;
            st=temp;
            return st;
            break;
        case 2:
            st=temp;
            prev=st;
            while(temp->next!=NULL)
            {
                prev=temp;
                temp=temp->next;
            }
            prev->next=NULL;
            return st;
            break;
        case 3:
            st=temp;
            prev=st;
                    printf("ENTER THE DATA TO BE REMOVED\n");
            scanf("%d",&val);
            while(temp->data!=val)
            {
                prev=temp;
                temp=temp->next;
            }
            prev->next=temp->next;
            return st;
            break;
        default:
            printf("INVALID CHOICE\n");
            exit(0);
    }

}

我尝试分析我的上述程序。

我编译的程序如下

cc -pg linklistadv.c

然后我运行程序如下

./a.out 
MENU
----
1.INSERT
2.DELETE
3.PRINT
4.EXIT
ENTER YOUR CHOICE:1
ENTER THE DATA TO INSERT:1
MENU
----
1.INSERT AT FIRST
2.INSERT AT LAST 
3.INSERT AT THE MIDDLE
ENTER YOUR CHOICE:1
NEW NODE INSERTED SUCCESSFULLY
MENU
----
1.INSERT
2.DELETE
3.PRINT
4.EXIT
ENTER YOUR CHOICE:3
THE LINKED LIST
---------------
1
MENU
----
1.INSERT
2.DELETE
3.PRINT
4.EXIT
ENTER YOUR CHOICE:4

现在我使用gprof命令如下gprof -p a.out gmon.out

但它显示的输出如下

Flat profile:

Each sample counts as 0.01 seconds.
 no time accumulated

  %   cumulative   self              self     total           
 time   seconds   seconds    calls  Ts/call  Ts/call  name    
  0.00      0.00     0.00        1     0.00     0.00  display
  0.00      0.00     0.00        1     0.00     0.00  insert

 %         the percentage of the total running time of the
time       program used by this function.

cumulative a running sum of the number of seconds accounted
 seconds   for by this function and those listed above it.

 self      the number of seconds accounted for by this
seconds    function alone.  This is the major sort for this
           listing.

calls      the number of times this function was invoked, if
           this function is profiled, else blank.

 self      the average number of milliseconds spent in this
ms/call    function per call, if this function is profiled,
       else blank.

 total     the average number of milliseconds spent in this
ms/call    function and its descendents per call, if this 
       function is profiled, else blank.

name       the name of the function.  This is the minor sort
           for this listing. The index shows the location of
       the function in the gprof listing. If the index is
       in parenthesis it shows where it would appear in
       the gprof listing if it were to be printed.

有什么问题吗？为什么统计时间显示为 0.00？显示功能将运行 100 秒。但它只显示时间为 0.00。请指导我。

提前致谢!

Answer 1

sleep(100) 不使用 100 秒的 CPU 时间。相反，操作系统的内核会暂停程序执行。 gprof 仅测量已用 CPU 时间，而不是程序挂起的时间。您可能想要搜索“CPU 时间”和“wallclock 时间”的解释。