Re: [lwip-users] Rapid tcp sending leads to a very long chain of pbufs

[address@hidden]

Muhamad Ikhwan Ismail wrote:
> Another question would be, is there a way for me to force TCP to send 
> instead queueing ? Like some kind of flush function?
If you always want to send right away, use the TCP_NODELAY socketoption 
like Fabian said. If you only want to flush at certain points, you _can_ 
set TCP_NODELAY and set it back again, but that's kind of slow...

The truth is that lwIP does not perform well in situations where you 
send byte per byte, but tell me a platform that does...


As to the limit of your hardware to 12 pbufs max: you can achieve this 
by setting TCP_SND_QUEUELEN to 16 but this is also not very performant 
since data is held back until the previous pbufs are sent and acked.

The two possible solutions you have right now are either to modify your 
ethernet driver or to redesign your application to not call send() for 
each byte. The latter would of course be the better solution.


Simon