测量在Windows上使用GetProcessTimes CPU时间 [英] Measure CPU time on Windows using GetProcessTimes

问题描述

我想测量 CPU 一些功能的时间。我知道如何使用 GetProcessTimes ，但我有某种重新启动的实施是一个问题：

I would like to measure CPU time of some function. I know how to use GetProcessTimes, but I have a problem implementing it with some kind of 'restarting':

通常情况下，我会做这样的：

Normally, I would do it like this:

#include "stdafx.h"
#include <math.h>
#include <windows.h>

double cputimer()
{
    FILETIME createTime;
    FILETIME exitTime;
    FILETIME kernelTime;
    FILETIME userTime;

    if ( GetProcessTimes( GetCurrentProcess( ),
        &createTime, &exitTime, &kernelTime, &userTime ) != -1 )
    {
        SYSTEMTIME userSystemTime;
        if ( FileTimeToSystemTime( &userTime, &userSystemTime ) != -1 )
            return (double)userSystemTime.wHour * 3600.0 +
            (double)userSystemTime.wMinute * 60.0 +
            (double)userSystemTime.wSecond +
            (double)userSystemTime.wMilliseconds / 1000.0;
    }
}

int _tmain(int argc, _TCHAR* argv[])
{
    double start, stop;
    long sum = 0L;

    start = cputimer();
    for (long long i = 1; i < 10000000; i++){
        sum += log((double)i);
    }
    stop = cputimer();

    printf("Time taken: %f [seconds]\n", stop - start);

    return 0;
}

但随着复位我不知道我是否有正确的结果：

But with 'reset' I'm not sure if I have right results:

#include "stdafx.h"
#include <math.h>
#include <windows.h>

#define START    1
#define STOP    0

double cputimer(int reset)
{
    FILETIME createTime;
    FILETIME exitTime;
    FILETIME kernelTime;
    FILETIME userTime;

    double now = 0, then = 0;

    if ( GetProcessTimes( GetCurrentProcess( ),
        &createTime, &exitTime, &kernelTime, &userTime ) != -1 )
    {
        SYSTEMTIME userSystemTime;
        if ( FileTimeToSystemTime( &userTime, &userSystemTime ) != -1 )
            now = (double)userSystemTime.wHour * 3600.0 +
            (double)userSystemTime.wMinute * 60.0 +
            (double)userSystemTime.wSecond +
            (double)userSystemTime.wMilliseconds / 1000.0;
    }

    if(reset)
    {
        then = now;
    }
    else
    {
        then = now - then;
    }

    return then;
}

int _tmain(int argc, _TCHAR* argv[])
{
    double s;
    long sum = 0L;

    cputimer(START);
    for (long long i = 1; i < 10000000; i++){
        sum += log((double)i);
    }
    s = cputimer(STOP);


    printf("Time taken: %f [seconds]\n", s);

    return 0;
}

我是不是做正确吗？

Am I doing it correctly?

推荐答案

我建议你像这样在Windows上一个简单的解决方案去，如果过程不运行的时间过长：

I suggest you go with a simpler solution on Windows like this if your process does not run for too long:

#define WIN32_LEAN_AND_MEAN
#include <windows.h>

double getTime() {
  LARGE_INTEGER freq, val;
  QueryPerformanceFrequency(&freq);
  QueryPerformanceCounter(&val);
  return (double)val.QuadPart / (double)freq.QuadPart;
}

然后，你可以只使用这样的：

Then you could just use it like this:

double d0 = getTime();
// function to measure
double timeInMilliseconds = 1000* (getTime() - d0);

您可以换到这一点的函数来实现类似的行为作为你的code。

You could wrap this into a function to achieve similar behavior as your code.

double cputimer(int reset)
{
  static double startTime = 0;
  if(reset)
  {
    startTime = getTime();
    return 0.0;
  } else
  {
    return 1000* (getTime() - startTime);
  }
}

更新：如果真正意图是要查询的的 usertime 应该替换的getTime（）功能（由OP使用的），但在逻辑 cputimer（）保持不变。

UPDATE: If the real intention was to query for the usertime one should replace the getTime() function (with the one used by the OP) but the logic in cputimer() remains the same.

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