[lwip-users] tcp client using sockets

[kyle treleaven]

I'm building a tcp client using the sockets api in lwip.  Am running
on xilinx port to the ppc of virtex fpga.  I base my client on the
echo server example, and I've posted here before about the same thing.
 I changed the code incrementally, very slowly, testing the
performance at each phase.  Basically, the client broke at the very
last step.  Up until that point I had been testing the client against
a very simple echo server.  I'd send it an initial byte representing
the number of times I wanted it to relay a phrase back and forth with
the client, and then I would receive, reply, receive, reply and so
on... ie. write(), read(), write(), read(), write(), read().... in an
arbitrarily long sequence.

The client breaks when i no longer do things in that exact order: 
write(), read(), write(), read()...  That is to say I may still
receive the data, but only after a number of retransmit pushes from
the server, and with a delay of 10-20 seconds, which is clearly
unacceptable.  It's as though some interrupt or polling loop isn't
firing correctly, but all of the OS and lwip setup code remains
exactly as it was in the server example.  Has anybody else encountered
this?

Kyle