【问题标题】:how to run the function in parallel?如何并行运行该功能?
【发布时间】:2014-02-25 14:55:21
【问题描述】:
#define million 1000000L

timer_t firstTimerID, secondTimerID, thirdTimerID;
double Task2ms_Raster, Task10ms_Raster, Task100ms_Raster;

struct sockaddr_in addr, client;
int acceptSocket;
char buf[256];
long rc, sentbytes;
int port = 18033;


void TASK1(Task2ms_Raster)
{

     struct timespec start, stop;
     uint32 startTime, stopTime;

        if( (startTime = clock_gettime( CLOCK_REALTIME, &start)) == -1 ) {
          perror("clock gettime");

        }

        startTime =start.tv_sec + 0.0000001 * start.tv_nsec;
             //  printf("start time is %lf", StartTime);


       // return EXIT_SUCCESS;

    /* Trigger DAQ for the 2ms XCP raster. */
    if( XCPEVENT_DAQ_OVERLOAD & Xcp_DoDaqForEvent_2msRstr( ))
    {
        ++numDaqOverload2ms;
    }

    /* Update those variables which are modified every 2ms. */
 counter32 += slope32;

    /* Trigger STIM for the 2ms XCP raster. */
  if( enableBypass2ms )
   {
        if( XCPEVENT_MISSING_DTO & Xcp_DoStimForEvent_2msRstr( ) )
        {
     ++numMissingDto2ms;
        }
        }
  if( (stopTime = clock_gettime( CLOCK_REALTIME, &stop)) == -1 ) {
          perror( "clock gettime" );

        }
  stopTime =  stop.tv_sec + 0.0000001 * stop.tv_nsec;
    //printf("stop time is %ld", stopTime);

            duration2ms = (uint32)(stopTime- startTime);
           // printf( "time difference is= %ld\n", duration2ms );



}



void TASK3(Task100ms_Raster)
{
     struct timespec start, stop;
     uint32 startTime, stopTime;



            if( (startTime = clock_gettime( CLOCK_REALTIME, &start)) == -1 )
            {
              perror("clock gettime");

            }
           startTime =start.tv_sec + 0.0000001 * start.tv_nsec;
          // printf("start time is %lf", startTime);

    /* Trigger DAQ for the 100ms XCP raster. */
    if( XCPEVENT_DAQ_OVERLOAD & Xcp_DoDaqForEvent_100msRstr( ))
    {
        ++numDaqOverload100ms;
    }

    /* Update those variables which are modified every 100ms. */
    counter8 += slope8;


    /* Trigger STIM for the 100ms XCP raster. */
    if( enableBypass100ms )
    {
        if( XCPEVENT_MISSING_DTO & Xcp_DoStimForEvent_100msRstr( ) )
        {
            ++numMissingDto100ms;
        }
    }



    if((stopTime = clock_gettime( CLOCK_REALTIME, &stop)) == -1 ) {
              perror( "clock gettime" );

            }

    stopTime =  stop.tv_sec + 0.0000001 * stop.tv_nsec;
     // printf("stop time is %lf", stopTime);

    Xcp_CmdProcessor();

    duration100ms = ( stop.tv_sec - start.tv_sec )
                     + (double)( stop.tv_nsec - start.tv_nsec )
                       / (double)million;
          //  printf( "time difference is= %ld\n", duration100ms );
}

/*The handler checks that the value stored in sival_ptr matches a given timerID
variable.  The sival_ptr is the same as the one we set in makeTimer(),
though here it lives in a different structure.
Obviously, it got copied from there to here on the way to this signal handler.
The point is that the timerID is what is used to determine which timer just went off
and determine what to do next */


static void timerHandler( int sig, siginfo_t *si, void *uc )
{
    timer_t *tidp;

    tidp = si->si_value.sival_ptr;

    if ( *tidp == firstTimerID )

        TASK1(Task2ms_Raster);
   else if ( *tidp == secondTimerID )
       TASK2(Task10ms_Raster);
    else if ( *tidp == thirdTimerID )
        TASK3(Task100ms_Raster);
}

/*
The function takes a pointer to a timer_t variable that will be filled with the
timer ID created by timer_create().  This pointer is also saved in the sival_ptr
variable right before calling timer_create().  In this function notice that we
always use the SIGRTMIN signal, so expiration of any timer causes this signal to
be raised.  The signal handler I've written for that signal is timerHandler.
*/

 static int makeTimer( char *name, timer_t *timerID, int expireMS, int intervalMS )
{
    struct sigevent         te;
    struct itimerspec       its;
    struct sigaction        sa;
    int                     sigNo = SIGRTMIN;

    /* Set up signal handler. */
    sa.sa_flags = SA_SIGINFO;
    sa.sa_sigaction = timerHandler;
    sigemptyset(&sa.sa_mask);
    if (sigaction(sigNo, &sa, NULL) == -1)
    {
        perror("sigaction");
    }

    /* Set and enable alarm */
    te.sigev_notify = SIGEV_SIGNAL;
    te.sigev_signo = sigNo;
    te.sigev_value.sival_ptr = timerID;
    timer_create(CLOCK_REALTIME, &te, timerID);

    its.it_interval.tv_sec = 0;
    its.it_interval.tv_nsec = intervalMS * 1000000;
    its.it_value.tv_sec = 0;
    its.it_value.tv_nsec = expireMS * 1000000;
    timer_settime(*timerID, 0, &its, NULL);

    return 1;
}



int CreateSocket()
{

    socklen_t len = sizeof(client);
       // Socket creation for UDP

       acceptSocket=socket(AF_INET,SOCK_DGRAM,0);

       if(acceptSocket==-1)

       {

         printf("Failure: socket creation is failed, failure code\n");

         return 1;

       }

       else

       {

         printf("Socket started!\n");

       }

     memset(&addr, 0, sizeof(addr));

     addr.sin_family=AF_INET;

     addr.sin_port=htons(port);

     addr.sin_addr.s_addr=htonl(INADDR_ANY);

     rc=bind(acceptSocket,(struct sockaddr*)&addr,sizeof(addr));

     if(rc== -1)

     {

       printf("Failure: listen, failure code:\n");

       return 1;

     }

     else

     {

       printf("Socket an port %d \n",port);

     }


     if(acceptSocket == -1)
     {
         printf("Fehler: accept, fehler code:\n");

          return 1;
     }
     else
     {

     while(rc!=-1)
         {


         rc=recvfrom(acceptSocket,buf, 256, 0, (struct sockaddr*) &client, &len);
         if(rc==0)
         {
           printf("Server has no connection..\n");
           break;
         }
         if(rc==-1)
         {
             printf("something went wrong with data %s", strerror(errno));
           break;
         }


         XcpIp_RxCallback( (uint16) rc, (uint8*) buf, (uint16) port );


         //  create a timer

                makeTimer("First Timer", &firstTimerID, 2, 2);   //2ms
             makeTimer("Second Timer", &secondTimerID, 10, 10);    //10ms
                makeTimer("Third Timer", &thirdTimerID, 100, 100);  //100ms
          }


     }

       close(acceptSocket);



       return 0;

     }



int main()
{

     Xcp_Initialize();
     CreateSocket();
     return 0;
}




void XcpApp_IpTransmit( uint16 XcpPort,  Xcp_StatePtr8 pBytes, uint16 numBytes )
{


        if ((long)XcpPort==port){
                sentbytes = sendto(acceptSocket,(char*)pBytes,(long)numBytes,0, (struct sockaddr*)&client, sizeof(client));
        }
        XcpIp_TxCallback(port,(uint16)sentbytes);
    }

我正在研究客户端和服务器架构。服务器代码如上所示,我创建了一个套接字来通过 IP 地址和端口号接收来自客户端的请求。服务器正在等待来自客户端的请求并将响应发送回客户端。我还创建了每 2 毫秒、10 毫秒和 100 毫秒调用一次任务的计时器。我还没有为定时器任务创建一个单独的线程。刚刚创建了一个处理程序来处理(信号处理程序)。当客户端向服务器发送请求时,我会在 recvfrom api 中接收数据,然后它会调用 maketimer(为 2ms),之后它不会退出 2ms 任务。

客户端是一种工具(INCA),用于向服务器发送数据。我正在开发 linux 操作系统。

有人能告诉我上面的程序有什么问题吗??

【问题讨论】:

    标签: c linux multithreading timer


    【解决方案1】:

    您需要为 while(rc!=-1) 循环创建单独的线程,因为 recvfrom() 是一个阻塞函数。在新数据到来之前,它会将您的线程置于非活动状态。

    【讨论】:

    • 你能给我举个例子吗??
    • 您可以通过pthreads 在单独的线程中执行操作,但这可能不是必需的。您可能需要考虑使用非阻塞 I/O。
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