WaitableTimerTest2

main.cpp

#include <Windows.h>
#include <stdio.h>
#include <assert.h>

#define NANOSECONDS_PER_SECOND ( 1000000000LL )
#define NANOSECONDS_PER_TIMER ( 100LL )

int main()
{
    LARGE_INTEGER begin;
    LARGE_INTEGER end;
    LARGE_INTEGER timeToWait;

    int targetMisses = 0;
    int targetsMet = 0;
    LONGLONG averageMissAmount = 0LL;

    HANDLE timer = CreateWaitableTimer(NULL, TRUE, NULL);
    assert(timer != NULL);

    timeToWait.QuadPart = -10000LL; //10000 * 100 nanoseconds = 1 ms

    LARGE_INTEGER performanceCounterFrequency;//On my machine: 3312841, or 301.9 ns
    assert(QueryPerformanceFrequency(&performanceCounterFrequency));
    LONGLONG maxDelta = -timeToWait.QuadPart * NANOSECONDS_PER_TIMER * performanceCounterFrequency.QuadPart / NANOSECONDS_PER_SECOND;

    printf("timeToWait: %I64d ns\n", -timeToWait.QuadPart * NANOSECONDS_PER_TIMER);
    printf("maxDelta  : %I64d ticks\n", maxDelta);
    printf("frequency : %I64d ticks/second\n", performanceCounterFrequency.QuadPart);

    for( int i = 0; i < 100000; i++ )//100,000 iterations
    {
        assert(QueryPerformanceCounter(&begin));
        assert(SetWaitableTimer(timer, &timeToWait, 0, NULL, NULL, TRUE));
        assert(WaitForSingleObject(timer, INFINITE) == WAIT_OBJECT_0);
        assert(QueryPerformanceCounter(&end));

        LONGLONG delta = end.QuadPart - begin.QuadPart;
        if (delta > maxDelta)
        {
            targetMisses++;
            averageMissAmount += delta - maxDelta;
        }
        else
        { targetsMet++; }
    }

    printf("Targets missed: %d\n", targetMisses);
    printf("Targets met   : %d\n", targetsMet);

    averageMissAmount /= (LONGLONG)targetMisses;
    printf("Average miss amount: %I64d ticks\n", averageMissAmount);
    printf("Average miss amount: %I64d ns\n", (averageMissAmount * NANOSECONDS_PER_SECOND) / performanceCounterFrequency.QuadPart);

    printf("Press any key to exit...");
    getchar();
}