丁香色欲久久久久久综合网,日本精品久久久中文字幕,国产激情久久久久影院

使用API實現1/1000秒的性能測試類

// ?MbUnit?Test?Framework

// ?

// ?Copyright?(c)?2004?Jonathan?de?Halleux

// ?This?software?is?provided?'as-is',?without?any?express?or?implied?warranty.?

// ?

// ?In?no?event?will?the?authors?be?held?liable?for?any?damages?arising?from?

// ?the?use?of?this?software.

// ?Permission?is?granted?to?anyone?to?use?this?software?for?any?purpose,?

// ?including?commercial?applications,?and?to?alter?it?and?redistribute?it?

// ?freely,?subject?to?the?following?restrictions:

// ????????1.?The?origin?of?this?software?must?not?be?misrepresented;?

// ????????you?must?not?claim?that?you?wrote?the?original?software.?

// ????????If?you?use?this?software?in?a?product,?an?acknowledgment?in?the?product?

// ????????documentation?would?be?appreciated?but?is?not?required.

// ????????2.?Altered?source?versions?must?be?plainly?marked?as?such,?and?must?

// ????????not?be?misrepresented?as?being?the?original?software.

// ????????3.?This?notice?may?not?be?removed?or?altered?from?any?source?

// ????????distribution.

// ????????

// ????????MbUnit?HomePage:? http://mbunit.tigris.org

// ????????Author:?Jonathan?de?Halleux

using ?System;

using ?System.Runtime.InteropServices;

using ?System.ComponentModel;

using ?System.Threading;

namespace ?MbUnit.Core.Monitoring

{

???? /// ? <summary>

???? /// ?A?high?performance?timer

???? /// ? </summary>

???? /// ? <remarks>

???? /// ?High?Precision?Timer?based?on?Win32?methods.

???? /// ? </remarks>

???? /// ? <example>

???? /// ?This?example?times?the?execution?of?a?method:

???? /// ? <code>

???? /// ?TimeMonitor?timer?=?new?TimeMonitor();

???? /// ?timer.Start();

???? /// ????

?//?execute?code

???? /// ?timer.Stop();

???? /// ?

???? /// ?Console.WriteLine("Duration:?{0}",timer.Duration);

???? /// ? </example>

???? public ? class ?TimeMonitor

???? {

????????[DllImport( " Kernel32.dll " )]

???????? private ? static ? extern ? bool ?QueryPerformanceCounter( out ? long ?lpPerformanceCount);??

????????[DllImport( " Kernel32.dll " )]

???????? private ? static ? extern ? bool ?QueryPerformanceFrequency( out ? long ?lpFrequency);

????????

???????? private ? long ?startTime,?stopTime;

???????? private ? long ?now;

???????? private ? long ?freq;

????????

???????? /// ? <summary> Default?constructor </summary>

???????? /// ? <remarks> Initializes?the?timer. </remarks>

???????? public ?TimeMonitor()

???????? {

????????????startTime? = ? 0 ;

????????????stopTime?? = ? 0 ;

???????????? if ?(QueryPerformanceFrequency( out ?freq)? == ? false )

???????????? {

???????????????? // ?high-performance?counter?not?supported?

???????????????? throw ? new ?Win32Exception();?

????????????}

????????}

????????

???????? /// ? <summary> Gets?the?clock?frequency </summary>

???????? /// ? <value> Clock?frequency </value>

???????? public ? long ?Frequency

???????? {

???????????? get

???????????? {

???????????????? return ? this .freq;

????????????}

????????}

????????

???????? /// ? <summary> Starts?the?timer </summary>

???????? /// ? <remarks> Resets?the?duration?and?starts?the?timer </remarks>

???????? public ? void ?Start()

???????? {

???????????? // ?lets?do?the?waiting?threads?there?work

????????????Thread.Sleep( 0 );??

????????????QueryPerformanceCounter( out ?startTime);

????????}

????????

???????? /// ? <summary> Stops?the?timer </summary>

???????? /// ? <remarks> Stops?the?timer </remarks>

???????? public ? void ?Stop()

???????? {

????????????QueryPerformanceCounter( out ?stopTime);

????????}

????????

???????? /// ? <summary> Gets?the?current?duration?value?without?stopping?the?timer </summary>

???????? /// ? <value> Current?duration?value </value>

???????? public ? double ?Now

???????? {

???????????? get

???????????? {

????????????????QueryPerformanceCounter( out ?now);

???????????????? return ?( double )(now? - ?startTime)? / ?( double )?freq;

????????????} ????????

????????}

???????? /// ? <summary> Gets?the?timed?duration?value?in?seconds </summary>

???????? /// ? <value> Timer?duration </value>

???????? public ? double ?Duration

???????? {

???????????? get

???????????? {

???????????????? return ?( double )(stopTime? - ?startTime)? / ?( double )?freq;

????????????}

????????}

????}

}

c++版的:

High-resolution?timer?for?timing?code?fragments?

Timing?of?code?fragments?is?simple:?

record?the?start?time?

execute?the?code?

record?the?end?time?

calucate?the?difference?between?end?and?start?

For?timing?exuction?time?of?pieces?of?code?you?need?a?high-resolution?timer.?On?Windows,?Windows?CE?and?Pocket?PC/Smartphone?(which?are?Windows?CE?variations)?you?can?use?QueryPerformanceCounter?and?QueryPerformanceFrequence?API?calls.?

Here's?a?simple?implementation?in?C:?

typedef?struct?prof_timer_t?{

????LARGE_INTEGER?time_start;

????LARGE_INTEGER?time_stop;

}?prof_timer_t;

void?prof_timer_start(prof_timer_t?*timer)?{

????QueryPerformanceCounter(&timer->time_start);

}

void?prof_timer_stop(prof_timer_t?*timer)?{

????QueryPerformanceCounter(&timer->time_stop);

}

double?prof_timer_get_duration_in_secs(prof_timer_t?*timer)?{

????LARGE_INTEGER?freq;

????double?duration;

????QueryPerformanceFrequency(&freq);

????duration?=?(double)(timer->time_stop.QuadPart-timer->time_start.QuadPart)/(double)freq.QuadPart;

????return?duration;

}

And?in?C++:?

//?very?simple,?high-precision?(at?least?in?theory)?timer?for?timing?API?calls

struct?ProfTimer?{

????void?Start(void)?{

????????QueryPerformanceCounter(&mTimeStart);

????};

????void?Stop(void)?{

????????QueryPerformanceCounter(&mTimeStop);

????};

????double?GetDurationInSecs(void)

????{

????????LARGE_INTEGER?freq;

????????QueryPerformanceFrequency(&freq);

????????double?duration?=?(double)(mTimeStop.QuadPart-mTimeStart.QuadPart)/(double)freq.QuadPart;

????????return?duration;

????}

????LARGE_INTEGER?mTimeStart;

????LARGE_INTEGER?mTimeStop;

};

And?here's?an?example?of?using?the?C++?version:?

????ProfTimer?t;

????t.Start();

????foo();

????t.Stop();

????double?dur?=?t.GetDurationInSecs();

????printf("executing?foo()?took?%f?seconds\n"?,?dur);

posted on 2006-06-16 14:07 夢在天涯閱讀(1720) 評論(1) 編輯收藏引用所屬分類: CPlusPlus 、C#/.NET 、VS2005/2008

GetTickCount()和GetCurrentTime()都只精確到55ms(1個tick就是55ms)。如果要精確到毫秒，應該使用timeGetTime函數或QueryPerformanceCounter函數。
雖然timeGetTime返回值的單位是1ms，但實際上它的精度只有10ms左右。
如果想提高精度，可以使用QueryPerformanceCounter和QueryPerformanceFrequency。這兩個函數不是在每個系統中都支持。對于支持它們的系統中，可以獲得低于1ms的精度。Windows 內部有一個精度非常高的定時器, 精度在微秒級, 但不同的系統這個定時器的頻率不同, 這個頻率與硬件和操作系統都可能有關。利用 API 函數 QueryPerformanceFrequency 可以得到這個定時器的頻率。利用 API 函數 QueryPerformanceCounter 可以得到定時器的當前值。根據要延時的時間和定時器的頻率, 可以算出要延時的時間定時器經過的周期數。在循環里用 QueryPerformanceCounter 不停的讀出定時器值, 一直到經過了指定周期數再結束循環, 就達到了高精度延時的目的。回復更多評論

刷新評論列表

只有注冊用戶登錄后才能發表評論。
【推薦】100%開源！大型工業跨平臺軟件C++源碼提供，建模，組態！

相關文章: 動態鏈接庫dll 靜態鏈接庫lib 動態導入庫lib 2道C++面試題 .h頭文件 .lib庫文件 .dll動態鏈接庫文件關系 C++強大的背后 Lnuix/Unix上C++開發使用啥工具 C++對象模型 C++的異常[轉載] 《windows via C++》之windows線程同步 dynamic_cast使用的討論 C++ 虛函數表解析（轉）

網站導航: 博客園 IT新聞 BlogJava 博問 Chat2DB 管理

# re: 性能測試類 2006-06-16 14:26 夢在天涯

C++ Programmer's Cookbook

使用API實現1/1000秒的性能測試類

評論

公告

導航

統計

常用鏈接

隨筆分類

隨筆檔案

收藏夾

Blogs

c#(csharp)

C++(cpp)

Enlish

Forums(bbs)

My self

Often go

Useful Webs

Xml/Uml/html

搜索

積分與排名

最新評論

閱讀排行榜