std::mutex和CRITICAL_SECTION性能比较

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测试代码：

#include "stdafx.h"
#include <Windows.h>
#include <mutex>
#include <thread>
#include <vector>
#include <chrono>
#include <iostream>

const int tastCount = 160000;
int numThreads;
const int MAX_THREADS = 16;

double g_shmem = 8;
std::mutex g_mutex;
CRITICAL_SECTION g_critSec;

void sharedFunc(int i, double &data)
{
    for (int j = 0; j < 100; j++)
    {
        if (j % 2 == 0)
            data = sqrt(data);
        else
            data *= data;
    }
}

void threadFuncCritSec() {
    double lMem = 8;
    int iterations = tastCount / numThreads;
    for (int i = 0; i < iterations; ++i) {
        for (int j = 0; j < 100; j++)
            sharedFunc(j, lMem);
        EnterCriticalSection(&g_critSec);
        sharedFunc(i, g_shmem);
        LeaveCriticalSection(&g_critSec);
    }
    printf("results: %f\n", lMem);
}

void threadFuncMutex() {
    double lMem = 8;
    int iterations = tastCount / numThreads;
    for (int i = 0; i < iterations; ++i) {
        for (int j = 0; j < 100; j++)
            sharedFunc(j, lMem);
        g_mutex.lock();
        sharedFunc(i, g_shmem);
        g_mutex.unlock();
    }
    printf("results: %f\n", lMem);
}

void testRound()
{
    std::vector<std::thread> threads;

    auto startMutex = std::chrono::high_resolution_clock::now();
    for (int i = 0; i < numThreads; ++i)
        threads.push_back(std::thread(threadFuncMutex));
    for (std::thread& thd : threads)
        thd.join();
    auto endMutex = std::chrono::high_resolution_clock::now();

    std::cout << "std::mutex:       ";
    std::cout << std::chrono::duration_cast<std::chrono::milliseconds>(endMutex - startMutex).count();
    std::cout << "ms \n\r";

    threads.clear();
    auto startCritSec = std::chrono::high_resolution_clock::now();
    for (int i = 0; i < numThreads; ++i)
        threads.push_back(std::thread(threadFuncCritSec));
    for (std::thread& thd : threads)
        thd.join();
    auto endCritSec = std::chrono::high_resolution_clock::now();

    std::cout << "CRITICAL_SECTION: ";
    std::cout << std::chrono::duration_cast<std::chrono::milliseconds>(endCritSec - startCritSec).count();
    std::cout << "ms \n\r";
}

int _tmain(int argc, _TCHAR* argv[]) {
    InitializeCriticalSection(&g_critSec);

    std::cout << "Tasks: " << tastCount << "\n\r";

    for (numThreads = 1; numThreads <= MAX_THREADS; numThreads = numThreads * 2) {
        if (numThreads == 16)
            numThreads = 12;
        Sleep(100);
        std::cout << "Thread count: " << numThreads << "\n\r";
        testRound();
    }

    DeleteCriticalSection(&g_critSec);
    return 0;
}

测试环境VS2013

测试结果：

Tasks: 160000
Thread count: 1
std::mutex:       12096ms
CRITICAL_SECTION: 12060ms
Thread count: 2
std::mutex:       5206ms
CRITICAL_SECTION: 5110ms
Thread count: 4
std::mutex:       2643ms
CRITICAL_SECTION: 2625ms
Thread count: 8
std::mutex:       1632ms
CRITICAL_SECTION: 1702ms
Thread count: 12
std::mutex:       1227ms
CRITICAL_SECTION: 1244ms

本文标签： 性能stdmutexCRITICALSECTION