为什么当我连接了调试器/IDE 时我的 STL 代码运行如此缓慢?

Here are the times: (all Win32 builds)

• 调试，命令行:421ms
• 调试，来自 IDE:24,570 毫秒
• RELEASE，命令行:31ms
• 发布，来自 IDE:23,353 毫秒

代码:

#include <windows.h>
#include <iostream>

#include <set>
#include <algorithm>
using namespace std;

int runIntersectionTestAlgo()
{   

    set<int> set1;
    set<int> set2;
    set<int> intersection;


    // Create 100,000 values for set1
    for ( int i = 0; i < 100000; i++ )
    {
        int value = 1000000000 + i;
        set1.insert(value);
    }

    // Create 1,000 values for set2
    for ( int i = 0; i < 1000; i++ )
    {
        int random = rand() % 200000 + 1;
        random *= 10;

        int value = 1000000000 + random;
        set2.insert(value);
    }

    set_intersection(set1.begin(),set1.end(), set2.begin(), set2.end(), inserter(intersection, intersection.end()));

    return intersection.size(); 
}

int main(){
    DWORD start = GetTickCount();

    runIntersectionTestAlgo();

    DWORD span = GetTickCount() - start;

    std::cout << span << " milliseconds
";
}

推荐答案

在 Microsoft 调试器(windbg、kd、cdb、Visual Studio 调试器)下运行默认强制 Windows 使用调试堆而不是默认堆.在 Windows 2000 及更高版本上，默认堆是 低碎片堆，与调试堆相比，这非常好.您可以使用 HeapQueryInformation.