临界区比事件效率高多少呀?

对效率的要求很高吗？不高的话，怎么用方便怎么用。
或者自己用代码测试看看吧。// FastMutex.cpp : Defines the entry point for the console application.
//#include "stdafx.h"/* Define 4 MUTual EXclusion mechanisms:
*   Mutex: a plain mutex
*   FastMutex: a mutex
*   SpinMutex: a spinning mutex
*   NTCritical_Section: NT's critical section
*///----------------------------------------------------------------------------
// A plain NT mutex
class Mutex {
        HANDLE mux;
public:
        Mutex()
          : mux(CreateMutex(NULL,FALSE,NULL))
          {}
        ~Mutex()
          { CloseHandle(mux); }
        void Request()
          { WaitForSingleObject(mux,INFINITE); }
        void Release()
          { ReleaseMutex(mux); }
};//----------------------------------------------------------------------------
// A fast, but friendly, mutex
class FastMutex {
        LONG toggle;
        LONG waiters;
        HANDLE try_again;
public:
        FastMutex()
          : toggle(0),
            waiters(0),
            try_again(CreateEvent(NULL,TRUE,FALSE,NULL))
          {}
        ~FastMutex()
          { CloseHandle(try_again); }
        void Request();
        void Release();
};void FastMutex::Request() {
        InterlockedIncrement(&waiters);
        for(;;) {
                if(InterlockedExchange(&toggle,1)==0) {
                        InterlockedDecrement(&waiters);
                        return;
                }
                WaitForSingleObject(try_again,INFINITE);
                ResetEvent(try_again);
        }
}void FastMutex::Release() {
        toggle=0;
        if(waiters!=0)
                SetEvent(try_again);
}//----------------------------------------------------------------------------
// A very fast, but friendly, spinning mutex
// This is not a true spinlock since it will block the thread if spinning seems futileclass SpinMutex {
        enum {
          spin_retries=100 //tailor this value to suit you application/compiler
        };
        LONG toggle;
        LONG waiters;
        HANDLE try_again;
public:
        SpinMutex()
          : toggle(0),
            waiters(0),
            try_again(CreateEvent(NULL,TRUE,FALSE,NULL))
          {}
        ~SpinMutex()
          { CloseHandle(try_again); }
        void Request();
        void Release();
};void SpinMutex::Request() {
        for(unsigned spin=0; spin<spin_retries; spin++) {
                if(InterlockedExchange(&toggle,1)==0)
                        return;
        }
        InterlockedIncrement(&waiters);
        for(;;) {
                if(InterlockedExchange(&toggle,1)==0) {
                        InterlockedDecrement(&waiters);
                        return;
                }
                WaitForSingleObject(try_again,INFINITE);
                ResetEvent(try_again);
        }
}void SpinMutex::Release() {
        toggle=0;
        if(waiters!=0)
                SetEvent(try_again);
}//----------------------------------------------------------------------------
//NT's critical sections
class NTCritialSection {
        CRITICAL_SECTION cs;
public:
        NTCritialSection()
          { InitializeCriticalSection(&cs); }
        ~NTCritialSection()
          { DeleteCriticalSection(&cs); }
        void Request() {
                EnterCriticalSection(&cs);
        }
        void Release() {
                LeaveCriticalSection(&cs);
        }
};//   1: 9.359 9.093 9.125 9.250
//  10: 9.460 9.547 9.266 9.390
// 100: 9.281 9.250 9.500 9.359
//1000: 9.344 9.438 9.406 9.390#include <time.h>
#include <stdio.h>
//Uncomment one of these to test them
//Mutex mux;            //running time: 42.25/42.20/42.20
//FastMutex mux;        //running time: 3.73/4.48/4.45
//SpinMutex mux;        //running time: 0.94/0.94/0.94
NTCritialSection mux; //running time: 42.40/40.80/42.03static inline loop() {
        //spend some time ...
        for(unsigned i=0; i<1000000; i++) {
                mux.Request();
                mux.Release();
        }
}DWORD WINAPI OtherThread(LPVOID) {
        loop();
        ExitThread(0);
        return 0;
}int main(int,char**)
{
        clock_t start=clock();        HANDLE hThread;
        DWORD idThread;
        //create secondary thread
        hThread = CreateThread(NULL, 16384, OtherThread, NULL, 0, &idThread);
        //compete with the secondary thread
        loop();
        //wait for secondary thread to finish
        WaitForSingleObject(hThread,INFINITE);
        clock_t end=clock();
        CloseHandle(hThread);

        printf("Running time: %10.3f seconds\n", ((double)(end-start))/CLK_TCK );
        return 0;
}

临界区,简单点说就是自旋锁+互斥量.单个cpu上没有任何优势.多个cpu那要看你占用锁的时间了.如果时间很短(远小于一个时间片),自旋锁确实快点.占用时间很长的话,还不如互斥量.

看第134到138行代码
//Uncomment one of these to test them
//Mutex mux;            //running time: 42.25/42.20/42.20
//FastMutex mux;        //running time: 3.73/4.48/4.45
//SpinMutex mux;        //running time: 0.94/0.94/0.94
NTCritialSection mux; //running time: 42.40/40.80/42.03

我表示看不懂你写的代码
看第134到138行代码
//Uncomment one of these to test them
//Mutex mux;            //running time: 42.25/42.20/42.20
//FastMutex mux;        //running time: 3.73/4.48/4.45
//SpinMutex mux;        //running time: 0.94/0.94/0.94
NTCritialSection mux; //running time: 42.40/40.80/42.03

看第134到138行代码
//Uncomment one of these to test them
//Mutex mux;            //running time: 42.25/42.20/42.20
//FastMutex mux;        //running time: 3.73/4.48/4.45
//SpinMutex mux;        //running time: 0.94/0.94/0.94
NTCritialSection mux; //running time: 42.40/40.80/42.03
Uncomment one of these to test them
想测试什么的效率，就取消对应行的注释，重新编译运行。其实我想说的是：对效率的要求很高吗？没有特别要求的话，怎么用方便怎么用。最后，代码中的//running time测试结果是参考值，具体得看你使用的计算机。

调试易

临界区比事件效率高多少呀?

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