我不知道为啥我的 IOCP 的 numberOfConcurrentThreads 参数不起作用
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【中文标题】我不知道为啥我的 IOCP 的 numberOfConcurrentThreads 参数不起作用【英文标题】：I don't know why my IOCP's numberOfConcurrentThreads argument doesn't work我不知道为什么我的 IOCP 的 numberOfConcurrentThreads 参数不起作用 【发布时间】：2021-11-22 13:45:58 【问题描述】：我已阅读下面的材料并测试了一些代码。 Does IOCP creates its own threads?
我的代码如下：
#include <functional>
#include <stdio.h>
#include <iostream>
#include <crtdbg.h>
#include <conio.h>
#include <array>
#include <unordered_map>
using namespace std;
namespace IOCP_test
struct myOverlapped
OVERLAPPED overLapped;
int number;
;
DWORD WINAPI myCallBack(LPVOID completionPort)
DWORD NumberOfByteTransfered = 0;
VOID* CompletionKey = NULL;
OVERLAPPED* overlappedPointer = NULL;
while (true)
auto success = GetQueuedCompletionStatus(
(HANDLE)completionPort,
&NumberOfByteTransfered,
(LPDWORD)&CompletionKey,
&overlappedPointer,
INFINITE);
if (success)
myOverlapped* mO = (myOverlapped*)overlappedPointer;
while (true)
cout << mO->number << endl;
//Sleep(10);
//PostQueuedCompletionStatus(completionPort, 0, 0, overlappedPointer);
void IOCP_test()
// TODO: sleep을 안걸었는데.. 왜 5개 스레드가 모두 작동할까?
int workerThreadCount = 5;
HANDLE hIOCP = CreateIoCompletionPort(INVALID_HANDLE_VALUE, NULL, 0, 1);
vector<HANDLE> workerThreadVector;
DWORD NumberOfByteTransfered = 0;
VOID* CompletionKey = NULL;
OVERLAPPED* overlappedPointer = NULL;
for (DWORD i = 0; i < workerThreadCount; i++)
HANDLE WorkerThread = CreateThread(NULL, 0, myCallBack, hIOCP, 0, NULL);
workerThreadVector.push_back(WorkerThread);
myOverlapped a1;
a1.number = 1;
myOverlapped a2;
a2.number = 2;
myOverlapped a3;
a3.number = 3;
myOverlapped a4;
a4.number = 4;
myOverlapped a5;
a5.number = 5;
if (hIOCP)
PostQueuedCompletionStatus(hIOCP, 0, 0, (LPOVERLAPPED)&a1);
PostQueuedCompletionStatus(hIOCP, 0, 0, (LPOVERLAPPED)&a2);
PostQueuedCompletionStatus(hIOCP, 0, 0, (LPOVERLAPPED)&a3);
PostQueuedCompletionStatus(hIOCP, 0, 0, (LPOVERLAPPED)&a4);
PostQueuedCompletionStatus(hIOCP, 0, 0, (LPOVERLAPPED)&a5);
char key;
while (true)
key = _getch();
if (key == 'e')
break;
if (key == 'n')
cout << endl;
for (DWORD i = 0; i < workerThreadVector.size(); i++)
CloseHandle(workerThreadVector[i]);
if (hIOCP)
CloseHandle(hIOCP);
//IOCP_test::IOCP_test();
int main()
IOCP_test::IOCP_test();
_CrtDumpMemoryLeaks();
return 0;
我想，如果 numberOfConcurrentThreads 有效，那么应该只运行一个 cout '1' 的线程，而不是所有五个线程。
但是，结果如下。
所有重叠的工作都由工作线程处理..
为什么所有重叠的工作都由 5 个工作线程处理？ 我认为应该是 1 个工作线程，因为 numberOfConcurrentThreads 是 1。
我希望您的明智回答。 感谢您的阅读。
【问题讨论】：
和？你的代码什么都没有显示。 你没看到我上面的代码吗？ 一些代码，和？它与您关于 numberOfConcurrentThreads 的问题有何关系？ 抱歉迟到了。我整天都在工作。你可以在下面的链接上看到“numberOfConcurrentThreads”是什么。 docs.microsoft.com/en-us/windows/win32/api/ioapiset/… 这是函数'CreateIoCompletionPort'的第四个参数，它控制IOCP上正在运行的工作线程的数量。 【参考方案1】：我想通了。 这是因为我在工作线程的函数中调用了“cout”。 我认为 'cout' 为我的工作线程调用 IO 中断，它使 IOCP 向另一个工作线程发出信号。
我的测试代码如下。 您可以运行此代码，然后按除“e”以外的任何键。（“e”用于退出。） 您可以在 IOCP 中查看哪个工作线程在工作。
#include <functional>
#include <stdio.h>
#include <iostream>
#include <crtdbg.h>
#include <conio.h>
#include <array>
#include <unordered_map>
int iocp_test = -1;
namespace IOCP_test
struct myOverlapped
OVERLAPPED overLapped;
int number;
;
DWORD WINAPI myCallBack(LPVOID completionPort)
DWORD NumberOfByteTransfered = 0;
VOID* CompletionKey = NULL;
OVERLAPPED* overlappedPointer = NULL;
while (true)
auto success = GetQueuedCompletionStatus(
(HANDLE)completionPort,
&NumberOfByteTransfered,
(LPDWORD)&CompletionKey,
&overlappedPointer,
INFINITE);
if (success)
myOverlapped* mO = (myOverlapped*)overlappedPointer;
while (true)
iocp_test = mO->number;
//Sleep(10);
//PostQueuedCompletionStatus(completionPort, 0, 0, overlappedPointer);
void IOCP_test()
// sleep을 안걸었는데.. 왜 5개 스레드가 모두 작동할까?
// cout 같은 IO 인터럽트가 워커 스레드에서 호출되면 IOCP에서 그 스레드는 작업 중이 아닌 스레드로 판단하는 것 같다.
int workerThreadCount = 5;
HANDLE hIOCP = CreateIoCompletionPort(INVALID_HANDLE_VALUE, NULL, 0, 2);
vector<HANDLE> workerThreadVector;
DWORD NumberOfByteTransfered = 0;
VOID* CompletionKey = NULL;
OVERLAPPED* overlappedPointer = NULL;
for (DWORD i = 0; i < workerThreadCount; i++)
HANDLE WorkerThread = CreateThread(NULL, 0, myCallBack, hIOCP, 0, NULL);
workerThreadVector.push_back(WorkerThread);
myOverlapped a1;
a1.number = 1;
myOverlapped a2;
a2.number = 2;
myOverlapped a3;
a3.number = 3;
myOverlapped a4;
a4.number = 4;
myOverlapped a5;
a5.number = 5;
if (hIOCP)
PostQueuedCompletionStatus(hIOCP, 0, 0, (LPOVERLAPPED)&a1);
PostQueuedCompletionStatus(hIOCP, 0, 0, (LPOVERLAPPED)&a2);
PostQueuedCompletionStatus(hIOCP, 0, 0, (LPOVERLAPPED)&a3);
PostQueuedCompletionStatus(hIOCP, 0, 0, (LPOVERLAPPED)&a4);
PostQueuedCompletionStatus(hIOCP, 0, 0, (LPOVERLAPPED)&a5);
char key;
while (true)
key = _getch();
cout << iocp_test;
if (key == 'e')
break;
if (key == 'n')
cout << endl;
for (DWORD i = 0; i < workerThreadVector.size(); i++)
CloseHandle(workerThreadVector[i]);
if (hIOCP)
CloseHandle(hIOCP);
//IOCP_test::IOCP_test();
int main()
IOCP_test::IOCP_test();
_CrtDumpMemoryLeaks();
return 0;
【讨论】：
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