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send udp packets using NDK , questions on the TaskSleep function in socket

xing wang
Intellectual 340 points


I want to send data from the ddr3 to PC using ethernet  when given a GPIO interrupt, now I've finished transfer data using UDP, but to further improve the data rate, I have 

the following question.

My task is as follows:

void udp_test()
{
SOCKET send = INVALID_SOCKET; // Sender socket.
struct sockaddr_in sout1; // Sender socket address structure
int i=0,count=0;
char* senddata;
int sentCnt;
senddata=(char *)DDR3BASEADDRESS;
// Allocate the file environment for this task
fdOpenSession( TaskSelf() );

// Create the send socket
send = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
if( send == INVALID_SOCKET )
goto leave;

// Send socket: set Port = 5000, IP destination address = ANY
bzero( &sout1, sizeof(struct sockaddr_in) );
sout1.sin_family = AF_INET;
sout1.sin_len = sizeof( sout1 );
sout1.sin_port = htons(5000);

// Bind send socket
if ( bind( send, (PSA) &sout1, sizeof(sout1) ) < 0 )
{
printf("Send: %d",fdError());
goto leave;
}

//strcpy( sendBuffer, "Are you there?" );
for(i=0; i<1500; i++)
{
sendBuffer[i]=(char)i%(0xFF);
}
sout1.sin_addr.s_addr = inet_addr(UnicastAddr); // PC address is the destination
sout1.sin_port = htons(7); // Echo port (7) is where we want to send data
for(;;)
{
if(Ethernetswtich)
{
while(count++<1600)
{
do
{
//cycleDelay(5000);
TaskSleep(1);// this is a must,it means n ms send a packet ,it control the data rate
//0x040D2F65-0x03FFDCFA
sentCnt = sendto( send, senddata, 1024, 0, (PSA)&sout1, sizeof(sout1) );
}
while (sentCnt < 0);
senddata+=1024;// need to be direct back while finished
//printf (" Message sent to ethernet \n");
}
Ethernetswtich=0;
}
}

leave:
// We only get here on a fatal error - close the sockets
if( send != INVALID_SOCKET )
fdClose( send );

printf("Fatal Error\n");

// This task is killed by the system - here, we block
TaskBlock( TaskSelf() );
}

 as I see the function TaskSleep(1); is essential in the packet sending.  for  TaskSleep(1), the data rate can be 1MB/s. but I can't make it higher.

without the TaskSleep function or replace it with the cycleDelay(5000) function,  i  can't recieve any packet in wireshark on PC.

the cycleDelay() is as follows:

void cycleDelay (uint32_t count)

{

  uint32_t sat;

 

  if (count <= 0)

    return;

 

  sat = TSCL + count;

  while (TSCL < sat);

}


Why would i have to suspend the Task to send UDP packet?  is the speed has some limitation, so i can only reach 1MB/s?

do any one have some suggustions?

Thanks!!!

  • 0
    TI__Intellectual 2745 points

    I'm attaching a file which is based off your code but uses fdSelect instead.  This allows sending of the packet as soon as the socket is available.  Could you try this and let me know if you see improvement?

    -John Demery

    Fullscreen 6327.test.c Download 
    /*
 * test.c
 *
 *  Created on: Jun 24, 2013
 *      Author: dilbert
 */

#include <ti/ndk/inc/netmain.h>


void udp_test()
{
	SOCKET send = INVALID_SOCKET; // Sender socket.
	struct sockaddr_in sout1; // Sender socket address structure
	int i=0,count=0, tmp;
	char* senddata;
	int sentCnt;

    // added these vars
	struct   	timeval 	to;
    fd_set ibits, obits, xbits;

	senddata=(char *)DDR3BASEADDRESS;

	// Allocate the file environment for this task
	fdOpenSession( TaskSelf() );

	// Create the send socket
	send = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
	if( send == INVALID_SOCKET )
		goto leave;

	// Send socket: set Port = 5000, IP destination address = ANY
	bzero( &sout1, sizeof(struct sockaddr_in) );
	sout1.sin_family = AF_INET;
	sout1.sin_len = sizeof( sout1 );
	sout1.sin_port = htons(5000);

	// Configure our socket timeout to be 15 seconds
	to.tv_sec  = 3;
	to.tv_usec = 0;

	setsockopt( send, SOL_SOCKET, SO_RCVTIMEO, &to, sizeof( to ) );

	// Bind send socket
	if ( bind( send, (PSA) &sout1, sizeof(sout1) ) < 0 )
	{
		printf("Send: %d",fdError());
		goto leave;
	}

	//strcpy( sendBuffer, "Are you there?" );
	for(i=0; i<1500; i++)
	{
		sendBuffer[i]=(char)i%(0xFF);
	}

	sout1.sin_addr.s_addr = inet_addr(UnicastAddr); // PC address is the destination
	sout1.sin_port = htons(7); // Echo port (7) is where we want to send data

	for(;;)
	{
		if(Ethernetswtich)
		{
			while(count++<1600)
			{
				do
				{
					// Clear the select flags
					FD_ZERO(&ibits);
					FD_ZERO(&obits);
					FD_ZERO(&xbits);

					// We examine the UDP socket (since we got called by data coming in, this is rather pointless, but rather an exercise in using these functions)
					FD_SET(send, &obits);

					tmp = fdSelect( 4, &ibits, &obits, &xbits, &to );

					if( tmp < 0 )
						goto leave;

					if( FD_ISSET(send, &obits) )
					{
						//0x040D2F65-0x03FFDCFA
						sentCnt = sendto( send, senddata, 1024, 0, (PSA)&sout1, sizeof(sout1) );
					}
				}
				while (sentCnt < 0);
				senddata+=1024;// need to be direct back while finished
				//printf (" Message sent to ethernet \n");
			}
			Ethernetswtich=0;
		}
	}

	leave:
	// We only get here on a fatal error - close the sockets
	if( send != INVALID_SOCKET )
	fdClose( send );

	printf("Fatal Error\n");

	// This task is killed by the system - here, we block
	TaskBlock( TaskSelf() );
}

  • 0 in reply to John Demery
    Intellectual 340 points

    dear Demery

    It seems not working, I change the function and can't recieve the packet on PC using wireshark. but i can debug and see the sentCnt=1024 which means  the socket has sent the packet?

    // Clear the select flags
    FD_ZERO(&ibits);
    FD_ZERO(&obits);
    FD_ZERO(&xbits);

    // We examine the UDP socket (since we got called by data coming in, this is rather pointless, but rather an exercise in using these functions)
    FD_SET(send, &obits);

    tmp = fdSelect( 4, &ibits, &obits, &xbits, &to );

    sorry to ask, but because i'm not that familiar with socket, what does this mean ?

  • 0 in reply to xing wang
    Genius 3715 points

    Please note that there is a potential problem with the NIMU driver dropping packets when sending UDP packets in a loop:
    http://e2e.ti.com/support/dsp/c6000_multi-core_dsps/f/639/t/273906.aspx

    I think the fdSelect() solution only works with connected sockets.

    Ralf

  • 0 in reply to Ralf Goebel
    Intellectual 340 points

    Thank you for your reply, but the URL is my post^^^^^^^^^^