RE: [lwip-users] enqueing problem

[Kieran Mansley]

On Sun, 2011-03-27 at 15:40 +0200, Noam weissman wrote:
> 
> I do understand that on every call to tcp_write the snd_queuelen is
> incremented but I do not understand why it is not 
> decremented when I call  tcp_output. Also take into consideration that
> I have closed NGLE so it should have worked ??

I think there's a little confusion here.  Simon said "The only thing
changed by disabling nagle is that tcp_output always sends everything
that is enqueued." but this isn't quite right.  Disabling Nagle's
algorithm stops us delaying transmission when there are small writes and
packets are already in flight.  It doesn't stop us delaying transmission
for other reasons, so tcp_output() won't always send everything that is
enqueued.  For example, if we have run out of congestion window or
receive window we will be unable to send immediately.  I think this will
explain what you see, particularly as the initial value for the
congestion window is quite small.

A packet capture would be useful to see what is happening on the wire.
Detail about how large your sends are would also help.

Kieran