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  4. threads and their time slots. [modified]

threads and their time slots. [modified]

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  • S Souldrift

    Good morning :), just a brief question. I got a multi-threaded program. Now is it possible to ensure that a certain thread at a certain point won´t lose its 'working permission'. Hm, don´t know if I expressed that correctly. I have a thread going into a function where it has to wait for a previously defined time, then go on. The thing is, it waits and waits and at some point its time slot is taken away. When it is given the next slot, though, the time it has waited for has 'long' passed. And thus it´s always too late. The code in question is:

    int RTPEngine::SendRTPPacket( BYTE* data, int size )
    {
    if( data && size > 0 && m_pHeader )
    {
    m_pLogger->Out(Logger::DEBUG, "RTPEngine: Sending data package with size %d (excluding header).\n", size);

    	BYTE\* packet = new BYTE\[size+12\];
    	BYTE\* headerBytes = m\_pHeader->GetInc();
    
    	for( int i = 0; i < 12; i++ )
    	{
    		packet\[i\] = headerBytes\[i\];
    	}
    	for( int i = 0; i < size; i++ )
    	{
    		packet\[i+12\] = data\[i\];
    	}
    
    	double now = 0.0; // milliseconds
    	if( m\_dPacketSendTime != 0.0 )
    	{
    		now = ((double) clock() / CLK\_TCK) \* 1000; // milliseconds
    		int tmp = 0;
    		//m\_pLogger->Out( Logger::DEBUG, "RTPEngine: Time now = %f.\\n", now );
    		while( now <= m\_dPacketSendTime )
    		{
    			if( tmp >= 20 )
    			{
    				m\_pLogger->Out( Logger::DEBUG, "RTPEngine: Time now = %f, send time = %f.\\n", now, m\_dPacketSendTime );
    				tmp = 0;
    			}
    			tmp++;
    			now = ((double) clock() / CLK\_TCK) \* 1000;
    		}
    	}
    
    	now = ((double) clock() / CLK\_TCK) \* 1000;
    	int rc=sendto(m\_oUDPSocket,(char\*)packet,size+12,0,(SOCKADDR\*)&m\_oUDPAddress,sizeof(SOCKADDR\_IN));
    
    	m\_pLogger->Out( Logger::DEBUG, "RTPEngine: Packet sent at = %f.\\n", now );
    
    	m\_dPacketSendTime = ((double) clock() / CLK\_TCK) \* 1000; // milliseconds
    	m\_dPacketSendTime += (m\_dPacketLengthMillis\*(1.0 - m\_dRTPOverlap));
    	m\_pLogger->Out( Logger::DEBUG, "RTPEngine: Next send time = %f.\\n", m\_dPacketSendTime );
    
    	return size;
    }
    else
    	return 0;
    

    }

    And one more thing is, on my Vista machine it works fine. The logger prints this: RTPEngine: Next send time = 53637.795918. RTPEngine: Sending data package with size 480 (excluding header). RTPEngine: Time now = 53628.000000, send time = 53637.795918. . . . RTPEngine: Time now = 53636.000000, send time = 53637.795918. RTPEngine: Time now = 53636.000000, send time = 53637.795918. RTPEngine: Time now = 53637.000000, send time = 53637.795918. RTPEngine: Time now = 536

    S Offline
    S Offline
    Souldrift
    wrote on last edited by
    #12

    I just found something else. A little disturbing. On our server machine (WIN XP) the Timer ALWAYS sleeps for 15.625ms. If it goes to sleep at all, that is. So this seems to be some kind of minimum time-slice (or a multiplied version of it). On my own developing computer (Vista) I don´t have theis kind of time-slices. The Timer sleeps for 9ms, then for 10ms and thereafter for 8ms. Does anybody now if one can manually control these time-slices? Souldrift

    K 1 Reply Last reply
    0
    • S Souldrift

      I just found something else. A little disturbing. On our server machine (WIN XP) the Timer ALWAYS sleeps for 15.625ms. If it goes to sleep at all, that is. So this seems to be some kind of minimum time-slice (or a multiplied version of it). On my own developing computer (Vista) I don´t have theis kind of time-slices. The Timer sleeps for 9ms, then for 10ms and thereafter for 8ms. Does anybody now if one can manually control these time-slices? Souldrift

      K Offline
      K Offline
      Keith Worden
      wrote on last edited by
      #13

      There's some references on the web to the minimum timer period being 10 ms for uniprocessor systems and 15 ms for multiprocessor. It could also be different depending on whether it's 32 or 64 bit Windows. The minimum on my system seems to be 15 ms - that's on Vista 32-bit with a dual-core processor.

      S 1 Reply Last reply
      0
      • K Keith Worden

        There's some references on the web to the minimum timer period being 10 ms for uniprocessor systems and 15 ms for multiprocessor. It could also be different depending on whether it's 32 or 64 bit Windows. The minimum on my system seems to be 15 ms - that's on Vista 32-bit with a dual-core processor.

        S Offline
        S Offline
        Souldrift
        wrote on last edited by
        #14

        Yeah, this would make our efforts kind of hopeless. But I just found out another little something. It doesn´t seem to be a Vista-XP-thing. But a network-thing. Whatever computer I use as a server, as long as the client comes in via network, the timer sleeps like 15.something millis. If server and client are on the same machine, there doesn´t seem to be a minimum time-slice (or it´s below what I saw so far). The timer sleeps as long (or brief) as I want. Souldrift

        1 Reply Last reply
        0
        • S Souldrift

          Good morning :), just a brief question. I got a multi-threaded program. Now is it possible to ensure that a certain thread at a certain point won´t lose its 'working permission'. Hm, don´t know if I expressed that correctly. I have a thread going into a function where it has to wait for a previously defined time, then go on. The thing is, it waits and waits and at some point its time slot is taken away. When it is given the next slot, though, the time it has waited for has 'long' passed. And thus it´s always too late. The code in question is:

          int RTPEngine::SendRTPPacket( BYTE* data, int size )
          {
          if( data && size > 0 && m_pHeader )
          {
          m_pLogger->Out(Logger::DEBUG, "RTPEngine: Sending data package with size %d (excluding header).\n", size);

          	BYTE\* packet = new BYTE\[size+12\];
          	BYTE\* headerBytes = m\_pHeader->GetInc();
          
          	for( int i = 0; i < 12; i++ )
          	{
          		packet\[i\] = headerBytes\[i\];
          	}
          	for( int i = 0; i < size; i++ )
          	{
          		packet\[i+12\] = data\[i\];
          	}
          
          	double now = 0.0; // milliseconds
          	if( m\_dPacketSendTime != 0.0 )
          	{
          		now = ((double) clock() / CLK\_TCK) \* 1000; // milliseconds
          		int tmp = 0;
          		//m\_pLogger->Out( Logger::DEBUG, "RTPEngine: Time now = %f.\\n", now );
          		while( now <= m\_dPacketSendTime )
          		{
          			if( tmp >= 20 )
          			{
          				m\_pLogger->Out( Logger::DEBUG, "RTPEngine: Time now = %f, send time = %f.\\n", now, m\_dPacketSendTime );
          				tmp = 0;
          			}
          			tmp++;
          			now = ((double) clock() / CLK\_TCK) \* 1000;
          		}
          	}
          
          	now = ((double) clock() / CLK\_TCK) \* 1000;
          	int rc=sendto(m\_oUDPSocket,(char\*)packet,size+12,0,(SOCKADDR\*)&m\_oUDPAddress,sizeof(SOCKADDR\_IN));
          
          	m\_pLogger->Out( Logger::DEBUG, "RTPEngine: Packet sent at = %f.\\n", now );
          
          	m\_dPacketSendTime = ((double) clock() / CLK\_TCK) \* 1000; // milliseconds
          	m\_dPacketSendTime += (m\_dPacketLengthMillis\*(1.0 - m\_dRTPOverlap));
          	m\_pLogger->Out( Logger::DEBUG, "RTPEngine: Next send time = %f.\\n", m\_dPacketSendTime );
          
          	return size;
          }
          else
          	return 0;
          

          }

          And one more thing is, on my Vista machine it works fine. The logger prints this: RTPEngine: Next send time = 53637.795918. RTPEngine: Sending data package with size 480 (excluding header). RTPEngine: Time now = 53628.000000, send time = 53637.795918. . . . RTPEngine: Time now = 53636.000000, send time = 53637.795918. RTPEngine: Time now = 53636.000000, send time = 53637.795918. RTPEngine: Time now = 53637.000000, send time = 53637.795918. RTPEngine: Time now = 536

          S Offline
          S Offline
          Souldrift
          wrote on last edited by
          #15

          By the way. I want to thank all who tried and helped me (not only in this thread) so far. This forum has brought me forward quite a bit. I love the hivemind :). Cheers Souldrift

          1 Reply Last reply
          0
          • S Souldrift

            Good morning :), just a brief question. I got a multi-threaded program. Now is it possible to ensure that a certain thread at a certain point won´t lose its 'working permission'. Hm, don´t know if I expressed that correctly. I have a thread going into a function where it has to wait for a previously defined time, then go on. The thing is, it waits and waits and at some point its time slot is taken away. When it is given the next slot, though, the time it has waited for has 'long' passed. And thus it´s always too late. The code in question is:

            int RTPEngine::SendRTPPacket( BYTE* data, int size )
            {
            if( data && size > 0 && m_pHeader )
            {
            m_pLogger->Out(Logger::DEBUG, "RTPEngine: Sending data package with size %d (excluding header).\n", size);

            	BYTE\* packet = new BYTE\[size+12\];
            	BYTE\* headerBytes = m\_pHeader->GetInc();
            
            	for( int i = 0; i < 12; i++ )
            	{
            		packet\[i\] = headerBytes\[i\];
            	}
            	for( int i = 0; i < size; i++ )
            	{
            		packet\[i+12\] = data\[i\];
            	}
            
            	double now = 0.0; // milliseconds
            	if( m\_dPacketSendTime != 0.0 )
            	{
            		now = ((double) clock() / CLK\_TCK) \* 1000; // milliseconds
            		int tmp = 0;
            		//m\_pLogger->Out( Logger::DEBUG, "RTPEngine: Time now = %f.\\n", now );
            		while( now <= m\_dPacketSendTime )
            		{
            			if( tmp >= 20 )
            			{
            				m\_pLogger->Out( Logger::DEBUG, "RTPEngine: Time now = %f, send time = %f.\\n", now, m\_dPacketSendTime );
            				tmp = 0;
            			}
            			tmp++;
            			now = ((double) clock() / CLK\_TCK) \* 1000;
            		}
            	}
            
            	now = ((double) clock() / CLK\_TCK) \* 1000;
            	int rc=sendto(m\_oUDPSocket,(char\*)packet,size+12,0,(SOCKADDR\*)&m\_oUDPAddress,sizeof(SOCKADDR\_IN));
            
            	m\_pLogger->Out( Logger::DEBUG, "RTPEngine: Packet sent at = %f.\\n", now );
            
            	m\_dPacketSendTime = ((double) clock() / CLK\_TCK) \* 1000; // milliseconds
            	m\_dPacketSendTime += (m\_dPacketLengthMillis\*(1.0 - m\_dRTPOverlap));
            	m\_pLogger->Out( Logger::DEBUG, "RTPEngine: Next send time = %f.\\n", m\_dPacketSendTime );
            
            	return size;
            }
            else
            	return 0;
            

            }

            And one more thing is, on my Vista machine it works fine. The logger prints this: RTPEngine: Next send time = 53637.795918. RTPEngine: Sending data package with size 480 (excluding header). RTPEngine: Time now = 53628.000000, send time = 53637.795918. . . . RTPEngine: Time now = 53636.000000, send time = 53637.795918. RTPEngine: Time now = 53636.000000, send time = 53637.795918. RTPEngine: Time now = 53637.000000, send time = 53637.795918. RTPEngine: Time now = 536

            S Offline
            S Offline
            Souldrift
            wrote on last edited by
            #16

            One last thought. I just tried to not let the thread sleep or create a wait object or anything. I simply went into a while-loop. Endlessly. Where I fetched and printed the system time. This was the result

            RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
            RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
            RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
            RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
            RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
            RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
            RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
            RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
            RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
            RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
            RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
            RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
            RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
            RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
            RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
            RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
            RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
            RTPEngine: Time now = 128911153781614000.000000, send time = 12891115378155.598000.
            RTPEngine: Time now = 128911153781614000.000000, send time = 12891115378155.598000.
            RTPEngine: Time now = 128911153781614000.000000, send time = 12891115378155.598000.
            RTPEngine: Time now = 128911153781614000.000000, send time = 12891115378155.598000.
            RTPEngine: Time now = 128911153781614000.000000, send time = 12891115378155.598000.
            RTPEngine: Time now = 128911153781614000.000000, send time = 12891115378155.598000.
            RTPEngine: Time now = 128911153781614000.000000, send time = 12891115378155.598000.
            RTPEngine: Time now = 128911153781614000.000000, send time = 12891115378155.598000.
            RTPEngine: Time now = 128911153781614000.000000, send time = 12891115378155.598000.
            RTPEngine: Time now = 128911153781614000.000000, send time = 12891115378155.598000.
            RTPEngine: Time now = 128911153781614000.000000

            S R 2 Replies Last reply
            0
            • S Souldrift

              One last thought. I just tried to not let the thread sleep or create a wait object or anything. I simply went into a while-loop. Endlessly. Where I fetched and printed the system time. This was the result

              RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
              RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
              RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
              RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
              RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
              RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
              RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
              RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
              RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
              RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
              RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
              RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
              RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
              RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
              RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
              RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
              RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
              RTPEngine: Time now = 128911153781614000.000000, send time = 12891115378155.598000.
              RTPEngine: Time now = 128911153781614000.000000, send time = 12891115378155.598000.
              RTPEngine: Time now = 128911153781614000.000000, send time = 12891115378155.598000.
              RTPEngine: Time now = 128911153781614000.000000, send time = 12891115378155.598000.
              RTPEngine: Time now = 128911153781614000.000000, send time = 12891115378155.598000.
              RTPEngine: Time now = 128911153781614000.000000, send time = 12891115378155.598000.
              RTPEngine: Time now = 128911153781614000.000000, send time = 12891115378155.598000.
              RTPEngine: Time now = 128911153781614000.000000, send time = 12891115378155.598000.
              RTPEngine: Time now = 128911153781614000.000000, send time = 12891115378155.598000.
              RTPEngine: Time now = 128911153781614000.000000, send time = 12891115378155.598000.
              RTPEngine: Time now = 128911153781614000.000000

              S Offline
              S Offline
              Stuart Dootson
              wrote on last edited by
              #17

              Souldrift wrote:

              And so on ... it always jumps 15,6ms forward

              Here's what Mark Russinovitch and David Solomon say in Windows Internals

              _

              On Windows 2000 Professional and Windows XP, threads run by default for 2 clock intervals; on Windows Server systems, by default, a thread runs for 12 clock intervals. The rationale for the longer default value on server systems is to minimize context switching. By having a longer quantum, server applications that wake up as the result of a client request have a better chance of completing the request and going back into a wait state before their quantum ends

              The length of the clock interval varies according to the hardware platform. The frequency of the clock interrupts is up to the HAL, not the kernel. For example, the clock interval for most x86 uniprocessors is about 10 milliseconds and for most x86 multiprocessors it is about 15 milliseconds. (The actual clock rate is not exactly a round number of milliseconds—see the following experiment for a way to check the actual clock interval.)

              EXPERIMENT: Determining the Clock Interval Frequency

              The Windows GetSystemTimeAdjustment function returns the clock interval. To determine the clock interval, download and run the Clockres program[^] from http://www.sysinternals.com.

              _

              That kind of confirms what you're seeing (and what I see - which is 15.625, or 500/32). HOWEVER!!!! I steered you wrong with waitable timers. I mistook them for a TimerQueueTimer in my memory. Try this:

              #include <Windows.h>
              #include <tchar.h>
              #include <iostream>

              void ReportTime(const char* message, LONGLONG const& when)
              {
              std::cout << message << double(when)/10000.0 << std::endl;
              }

              LONG count;
              LARGE_INTEGER liStart, liEnd, liFreq;

              VOID CALLBACK DoSendHere(__in_opt LPVOID lpArgToCompletionRoutine,
              __in DWORD dwTimerLowValue,
              __in DWORD dwTimerHighValue)
              {
              QueryPerformanceCounter(&liEnd);
              count++;
              }

              void SendLoop()
              {
              HANDLE hTimerQueue = CreateTimerQueue();
              HANDLE hTimer;
              count = 0;
              CreateTimerQueueTimer(&hTimer, hTimerQueue, (WAITORTIMERCALLBACK)&DoSendHere, 0 , 1, 1, WT_EXECU

              R S 2 Replies Last reply
              0
              • S Souldrift

                One last thought. I just tried to not let the thread sleep or create a wait object or anything. I simply went into a while-loop. Endlessly. Where I fetched and printed the system time. This was the result

                RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
                RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
                RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
                RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
                RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
                RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
                RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
                RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
                RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
                RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
                RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
                RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
                RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
                RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
                RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
                RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
                RTPEngine: Time now = 128911153781458000.000000, send time = 12891115378155.598000.
                RTPEngine: Time now = 128911153781614000.000000, send time = 12891115378155.598000.
                RTPEngine: Time now = 128911153781614000.000000, send time = 12891115378155.598000.
                RTPEngine: Time now = 128911153781614000.000000, send time = 12891115378155.598000.
                RTPEngine: Time now = 128911153781614000.000000, send time = 12891115378155.598000.
                RTPEngine: Time now = 128911153781614000.000000, send time = 12891115378155.598000.
                RTPEngine: Time now = 128911153781614000.000000, send time = 12891115378155.598000.
                RTPEngine: Time now = 128911153781614000.000000, send time = 12891115378155.598000.
                RTPEngine: Time now = 128911153781614000.000000, send time = 12891115378155.598000.
                RTPEngine: Time now = 128911153781614000.000000, send time = 12891115378155.598000.
                RTPEngine: Time now = 128911153781614000.000000, send time = 12891115378155.598000.
                RTPEngine: Time now = 128911153781614000.000000

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                R Offline
                Roger Stoltz
                wrote on last edited by
                #18

                Souldrift wrote:

                it always jumps 15,6ms forward

                I doubt the granularity and accuracy of the time value returned by ::GetSystemTimeAsFileTime(). Even though the FILETIME structure is a time value where the least significant bit represents 100 nanoseconds, it doesn't mean that it has an accuracy of 100 nanosecs. It's like looking at your watch, measuring a time with the needle showing seconds and then multiplying the value by 1,000,000 and claim you measured with microsecond accuracy. For time measurements of this kind you should you the performance timer; ::QueryPerformanceCounter() and ::QueryPerformanceFrequency(). It will give you the best accuracy available on your hardware. Read here[^] for more info on the high resolution performance counter.

                "It's supposed to be hard, otherwise anybody could do it!" - selfquote
                "High speed never compensates for wrong direction!" - unknown

                1 Reply Last reply
                0
                • S Stuart Dootson

                  Souldrift wrote:

                  And so on ... it always jumps 15,6ms forward

                  Here's what Mark Russinovitch and David Solomon say in Windows Internals

                  _

                  On Windows 2000 Professional and Windows XP, threads run by default for 2 clock intervals; on Windows Server systems, by default, a thread runs for 12 clock intervals. The rationale for the longer default value on server systems is to minimize context switching. By having a longer quantum, server applications that wake up as the result of a client request have a better chance of completing the request and going back into a wait state before their quantum ends

                  The length of the clock interval varies according to the hardware platform. The frequency of the clock interrupts is up to the HAL, not the kernel. For example, the clock interval for most x86 uniprocessors is about 10 milliseconds and for most x86 multiprocessors it is about 15 milliseconds. (The actual clock rate is not exactly a round number of milliseconds—see the following experiment for a way to check the actual clock interval.)

                  EXPERIMENT: Determining the Clock Interval Frequency

                  The Windows GetSystemTimeAdjustment function returns the clock interval. To determine the clock interval, download and run the Clockres program[^] from http://www.sysinternals.com.

                  _

                  That kind of confirms what you're seeing (and what I see - which is 15.625, or 500/32). HOWEVER!!!! I steered you wrong with waitable timers. I mistook them for a TimerQueueTimer in my memory. Try this:

                  #include <Windows.h>
                  #include <tchar.h>
                  #include <iostream>

                  void ReportTime(const char* message, LONGLONG const& when)
                  {
                  std::cout << message << double(when)/10000.0 << std::endl;
                  }

                  LONG count;
                  LARGE_INTEGER liStart, liEnd, liFreq;

                  VOID CALLBACK DoSendHere(__in_opt LPVOID lpArgToCompletionRoutine,
                  __in DWORD dwTimerLowValue,
                  __in DWORD dwTimerHighValue)
                  {
                  QueryPerformanceCounter(&liEnd);
                  count++;
                  }

                  void SendLoop()
                  {
                  HANDLE hTimerQueue = CreateTimerQueue();
                  HANDLE hTimer;
                  count = 0;
                  CreateTimerQueueTimer(&hTimer, hTimerQueue, (WAITORTIMERCALLBACK)&DoSendHere, 0 , 1, 1, WT_EXECU

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                  Roger Stoltz
                  wrote on last edited by
                  #19

                  Bah, you beat me to it... :-\

                  "It's supposed to be hard, otherwise anybody could do it!" - selfquote
                  "High speed never compensates for wrong direction!" - unknown

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                  • R Roger Stoltz

                    Bah, you beat me to it... :-\

                    "It's supposed to be hard, otherwise anybody could do it!" - selfquote
                    "High speed never compensates for wrong direction!" - unknown

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                    Stuart Dootson
                    wrote on last edited by
                    #20

                    Sorrreeeee :-O

                    Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

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                    • S Stuart Dootson

                      Sorrreeeee :-O

                      Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

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                      Roger Stoltz
                      wrote on last edited by
                      #21

                      :laugh:

                      "It's supposed to be hard, otherwise anybody could do it!" - selfquote
                      "High speed never compensates for wrong direction!" - unknown

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                      • S Stuart Dootson

                        Souldrift wrote:

                        And so on ... it always jumps 15,6ms forward

                        Here's what Mark Russinovitch and David Solomon say in Windows Internals

                        _

                        On Windows 2000 Professional and Windows XP, threads run by default for 2 clock intervals; on Windows Server systems, by default, a thread runs for 12 clock intervals. The rationale for the longer default value on server systems is to minimize context switching. By having a longer quantum, server applications that wake up as the result of a client request have a better chance of completing the request and going back into a wait state before their quantum ends

                        The length of the clock interval varies according to the hardware platform. The frequency of the clock interrupts is up to the HAL, not the kernel. For example, the clock interval for most x86 uniprocessors is about 10 milliseconds and for most x86 multiprocessors it is about 15 milliseconds. (The actual clock rate is not exactly a round number of milliseconds—see the following experiment for a way to check the actual clock interval.)

                        EXPERIMENT: Determining the Clock Interval Frequency

                        The Windows GetSystemTimeAdjustment function returns the clock interval. To determine the clock interval, download and run the Clockres program[^] from http://www.sysinternals.com.

                        _

                        That kind of confirms what you're seeing (and what I see - which is 15.625, or 500/32). HOWEVER!!!! I steered you wrong with waitable timers. I mistook them for a TimerQueueTimer in my memory. Try this:

                        #include <Windows.h>
                        #include <tchar.h>
                        #include <iostream>

                        void ReportTime(const char* message, LONGLONG const& when)
                        {
                        std::cout << message << double(when)/10000.0 << std::endl;
                        }

                        LONG count;
                        LARGE_INTEGER liStart, liEnd, liFreq;

                        VOID CALLBACK DoSendHere(__in_opt LPVOID lpArgToCompletionRoutine,
                        __in DWORD dwTimerLowValue,
                        __in DWORD dwTimerHighValue)
                        {
                        QueryPerformanceCounter(&liEnd);
                        count++;
                        }

                        void SendLoop()
                        {
                        HANDLE hTimerQueue = CreateTimerQueue();
                        HANDLE hTimer;
                        count = 0;
                        CreateTimerQueueTimer(&hTimer, hTimerQueue, (WAITORTIMERCALLBACK)&DoSendHere, 0 , 1, 1, WT_EXECU

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                        Souldrift
                        wrote on last edited by
                        #22

                        Uhh, thanks, I´ll try that out in a moment. Thanks for the writings on Windows Internals. Who could have known such a thing :). Very interesting. Two things, though. Why do you set a sleep time of 65ms (instead of infinite)? And I don´t see why this should circumvent the 15ms time-slice. QueryPerformanceCounter might 'see' higher resolution, but if the thread sleeps for 15ms, there´s nothing to see? Or is there? Souldrift

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                        0
                        • S Souldrift

                          Uhh, thanks, I´ll try that out in a moment. Thanks for the writings on Windows Internals. Who could have known such a thing :). Very interesting. Two things, though. Why do you set a sleep time of 65ms (instead of infinite)? And I don´t see why this should circumvent the 15ms time-slice. QueryPerformanceCounter might 'see' higher resolution, but if the thread sleeps for 15ms, there´s nothing to see? Or is there? Souldrift

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                          Stuart Dootson
                          wrote on last edited by
                          #23

                          The 65ms is just an example time - it can't be infinite because I want it to terminate :-) The thing that's seeing past the 15.625 timer resolution is the TimerQueueTimer. That has a resolution of 1ms. The program is intended to show that the timer callback is called with a resolution of 1ms, so could be used in your case, so long as your thread can remain the active thread.

                          Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

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                          0
                          • S Stuart Dootson

                            The 65ms is just an example time - it can't be infinite because I want it to terminate :-) The thing that's seeing past the 15.625 timer resolution is the TimerQueueTimer. That has a resolution of 1ms. The program is intended to show that the timer callback is called with a resolution of 1ms, so could be used in your case, so long as your thread can remain the active thread.

                            Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

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                            Souldrift
                            wrote on last edited by
                            #24

                            Okay, I thought so (after some thinking). Now if you will bear with me one more time, I´m not quite sure how to understand (handle) this regarding my case. For example if I use this (cause 9ms are appx. the time I need to wait before sending)

                            CreateTimerQueueTimer(&hTimer, hTimerQueue, (WAITORTIMERCALLBACK)&DoSendHere, 0 , 9, 1, WT_EXECUTEINTIMERTHREAD);
                            QueryPerformanceCounter(&liStart);
                            ::SleepEx(65, TRUE);

                            The callback func should with a 65ms sleep be called like 7 times. Though my log shows 54. I guess, this is because the timer doesn´t stop after my sleep or my sending. So the next question would be, how do I stop it? I know, i doesn´t even have to be periodic for what I need (so it would stop by itself), but I´m trying to understand the structure. I added a DeleteTimerQueueEx( hTimerQueue, NULL ); but it crashes now at that point. Souldrift Edit: And why does it not call the callback func when I take away the sleepEx()?? Is it dependant on the thread being asleep? If I do this

                            CreateTimerQueueTimer(&hTimer, hTimerQueue, (WAITORTIMERCALLBACK)&DoSendHere, 0 , 1, 0, WT_EXECUTEINTIMERTHREAD);
                            QueryPerformanceCounter(&liStart);
                            ::SleepEx(10, TRUE);

                            it doesn´t enter, either.

                            modified on Monday, July 6, 2009 4:32 AM

                            S 1 Reply Last reply
                            0
                            • S Souldrift

                              Okay, I thought so (after some thinking). Now if you will bear with me one more time, I´m not quite sure how to understand (handle) this regarding my case. For example if I use this (cause 9ms are appx. the time I need to wait before sending)

                              CreateTimerQueueTimer(&hTimer, hTimerQueue, (WAITORTIMERCALLBACK)&DoSendHere, 0 , 9, 1, WT_EXECUTEINTIMERTHREAD);
                              QueryPerformanceCounter(&liStart);
                              ::SleepEx(65, TRUE);

                              The callback func should with a 65ms sleep be called like 7 times. Though my log shows 54. I guess, this is because the timer doesn´t stop after my sleep or my sending. So the next question would be, how do I stop it? I know, i doesn´t even have to be periodic for what I need (so it would stop by itself), but I´m trying to understand the structure. I added a DeleteTimerQueueEx( hTimerQueue, NULL ); but it crashes now at that point. Souldrift Edit: And why does it not call the callback func when I take away the sleepEx()?? Is it dependant on the thread being asleep? If I do this

                              CreateTimerQueueTimer(&hTimer, hTimerQueue, (WAITORTIMERCALLBACK)&DoSendHere, 0 , 1, 0, WT_EXECUTEINTIMERTHREAD);
                              QueryPerformanceCounter(&liStart);
                              ::SleepEx(10, TRUE);

                              it doesn´t enter, either.

                              modified on Monday, July 6, 2009 4:32 AM

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                              Stuart Dootson
                              wrote on last edited by
                              #25

                              Souldrift wrote:

                              CreateTimerQueueTimer(&hTimer, hTimerQueue, (WAITORTIMERCALLBACK)&DoSendHere, 0 , 9, 1, WT_EXECUTEINTIMERTHREAD);

                              You're asking for a timer with an initial delay of 9ms and periodic delays after that of 1ms.

                              Souldrift wrote:

                              DeleteTimerQueueEx( hTimerQueue, NULL );

                              Think that should be DeleteTimerQueueTimer( hTimerQueue, hTimer, 0 );. That worked for me, anyway.

                              Souldrift wrote:

                              And why does it not call the callback func when I take away the sleepEx()?? Is it dependant on the thread being asleep?

                              The thread needs to be in an alertable state - look at the MSDN documentation[^] for what that means.

                              Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

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