c – 有意地浪费所有的主要记忆来学习分裂

Memory fragmentation in C: Design,implement,and run a C-program that does the following: it allocated memory for a sequence of of 3m arrays of size 500000 elements each; then it deallocates all even-numbered arrays and allocates a sequence of m arrays of size 700000 elements each. Measure the amounts of time your program requires for the allocations of the first sequence and for the second sequence. Choose m so that you exhaust all of the main memory available to your program. Explain your timings

我的执行情况如下：

#include <iostream>
#include <time.h>
#include <algorithm>

void main(){
    clock_t begin1,stop1,begin2,stop2;
    double tdif = 0,tdif2 = 0;
    for(int k=0;k<1000;k++){
    double dif,dif2;
    const int m = 50000;
    begin1 = clock();
    printf("Step Onen");
    int *container[3*m];
    for(int i=0;i<(3*m);i++)
    {
        int *tmpAry = (int *)malloc(500000*sizeof(int));
        container[i] = tmpAry;
    }
    stop1 = clock();
    printf("Step Twon");
    for(int i=0;i<(3*m);i+=2)
    {
    free(container[i]);
    }
    begin2 = clock();
    printf("Step Threen");
    int *container2[m];
    for(int i=0;i<m;i++)
    {
    int *tmpAry = (int *)malloc(700000*sizeof(int));
    container2[i] = tmpAry;
    }
    stop2 = clock();
    dif = (stop1 - begin1)/1000.00;
    dif2 = (stop2 - begin2)/1000.00;
    tdif+=dif;
    tdif/=2;
    tdif2+=dif2;
    tdif2/=2;
}
printf("To Allocate the first array it took: %.5fn",tdif);
printf("To Allocate the second array it took: %.5fn",tdif2);
system("pause");
};

我已经改变了这几种不同的方式,但我看到的一致性是,当我最初分配3 * m * 500000元素数组的内存,它占用了所有可用的主内存.但是当我告诉它释放它们时,内存不会释放到操作系统,所以当它分配m * 700000元素数组时,它会在页面文件(swap memory)中执行,因此它不会实际显示内存碎片.

上面的代码运行了1000次,平均值,需要相当长的一段时间.第一个序列平均值为2.06913秒,第二个序列为0.67594秒.对我来说,第二个序列应该花费更长的时间来显示碎片是如何工作的,但是由于使用了交换,所以不会发生.有没有办法解决这个问题,或者我假设错了？

我会问教授,我在星期一,但直到那时,任何帮助将不胜感激.