如何將計時器分辨率設置爲0.5 ms？

Question

我想將機器定時器分辨率設置爲0.5ms。

Sysinternal utility報告最小時鐘分辨率是0.5ms，因此可以完成。

P.S.我知道如何將它設置爲1ms。

P.P.S.我改變了它從C＃到更一般的問題（由於漢斯）

系統計時器分辨率

Answer 1

NtSetTimerResolution

示例代碼：

#include <windows.h> 

extern "C" NTSYSAPI NTSTATUS NTAPI NtSetTimerResolution(ULONG DesiredResolution, BOOLEAN SetResolution, PULONG CurrentResolution); 

... 

ULONG currentRes; 
NtSetTimerResolution(5000, TRUE, &currentRes); 

鏈路與ntdll.lib。

Answer 2

Timer.Interval = 500;

Answer 3

你需要爲它高分辨率定時器..你可以在這裏找到一些信息：http://www.codeproject.com/KB/cs/highperformancetimercshar.aspx

編輯：更多的信息可以在這裏找到：設置爲毫秒的十分之一; http://msdn.microsoft.com/en-us/library/aa964692(VS.80).aspx

Answer 4

您可以通過timeBeginPeriod和timeSetEvent獲得Win32 API的最佳時間爲1毫秒。也許你的HAL可以做得更好，但這是學術性的，你不能用C＃編寫設備驅動程序代碼。

Answer 5

您可能通過隱藏API NtSetTimerResolution()獲得0.5 ms分辨率。 NtSetTimerResolution由本機Windows NT庫NTDLL.DLL導出。請參閱MSDN上的How to set timer resolution to 0.5ms ?。不過，真正可實現的解決方案是由底層硬件決定的。現代硬件支持0.5毫秒的分辨率。 更多詳情請見Inside Windows NT High Resolution Timers。支持的分辨率可以通過調用NtQueryTimerResolution（）來獲得。

怎麼做：

#define STATUS_SUCCESS 0 
#define STATUS_TIMER_RESOLUTION_NOT_SET 0xC0000245 

// after loading NtSetTimerResolution from ntdll.dll: 

// The requested resolution in 100 ns units: 
ULONG DesiredResolution = 5000; 
// Note: The supported resolutions can be obtained by a call to NtQueryTimerResolution() 

ULONG CurrentResolution = 0; 

// 1. Requesting a higher resolution 
// Note: This call is similar to timeBeginPeriod. 
// However, it to to specify the resolution in 100 ns units. 
if (NtSetTimerResolution(DesiredResolution ,TRUE,&CurrentResolution) != STATUS_SUCCESS) { 
    // The call has failed 
} 

printf("CurrentResolution [100 ns units]: %d\n",CurrentResolution); 
// this will show 5000 on more modern platforms (0.5ms!) 

//  do your stuff here at 0.5 ms timer resolution 

// 2. Releasing the requested resolution 
// Note: This call is similar to timeEndPeriod 
switch (NtSetTimerResolution(DesiredResolution ,FALSE,&CurrentResolution) { 
    case STATUS_SUCCESS: 
     printf("The current resolution has returned to %d [100 ns units]\n",CurrentResolution); 
     break; 
    case STATUS_TIMER_RESOLUTION_NOT_SET: 
     printf("The requested resolution was not set\n"); 
     // the resolution can only return to a previous value by means of FALSE 
     // when the current resolution was set by this application  
     break; 
    default: 
     // The call has failed 

} 

注：NtSetTImerResolution的功能是通過使用布爾值Set基本上映射到功能timeBeginPeriod和timeEndPeriod（見Inside Windows NT High Resolution Timers有關該計劃的更多細節，所有的影響）。但是，多媒體套件將粒度限制爲毫秒，NtSetTimerResolution允許設置亞毫秒值。

Answer 6

如果您使用python，我寫了一個名爲wres的庫，它在內部調用NtSetTimerResolution。

pip install wres

import wres 

# Set resolution to 0.5 ms (in 100-ns units) 
# Automatically restore previous resolution when exit with statement 
with wres.set_resolution(5000): 
    pass