Network Write Delay using PPPD

Joel Sherrill joel.sherrill at OARcorp.com
Thu Jun 21 17:32:12 UTC 2001



Mike Siers wrote:
> 
> Hi,
> I am using the i386/pc586 BSP with the latest snapshot.  My code
> is using the standard pppd task to establish a network connection.
> The ppp connection gets established and I can create a socket and
> connect to my server test application.
> 
> The RTEMS client code will write a block of data every time it
> receives some data over the socket.  The problem that I am seeing
> is that the client write seems to be getting delayed.  And the
> delay keeps getting longer after each successive write.  After four
> writes, the delay is about 90 seconds!  I have turned off the pppd
> compression options.
> 
> I added some debug statements to the pppd code.  Basically it looks
> like the pppoutput function is getting called immediately but the
> modem_sendpacket function call gets delayed.
> 
> Has anyone seen this problem before?  Any thoughts or suggestions
> would be greatly appreciated.

grep'ing for delay, wake, and sleep (grep -i), see a number of places
where delays could be interjected.  Are your prints indicating that
any of these are hit?

Are you using something like the modem_example?  It seems to be waiting
on events before modem_sendpacket gets called.  What could delay the
send side?

> Thanks
> Mike Siers

-- 
Joel Sherrill, Ph.D.             Director of Research & Development
joel at OARcorp.com                 On-Line Applications Research
Ask me about RTEMS: a free RTOS  Huntsville AL 35805
Support Available                (256) 722-9985



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