Re: [lwip-users] tcp_enqueue fills but won't empty

[Christiaan Simons]

Matthew wrote:

> I also noticed that the UDP throughput has decreased in LwIP 1.1.1 vs.
> 1.1.0. Is there some change of option that changed that might account for
> this or is it just a side effect of other modifications to the code?

We've changed the lwip_standard_checksum() (inet.c) to
favor portability/correctness over performance.

Please note most IP stacks (e.g. BSD) use hand-crafted
assembly to get optimal checksum performance.
We cannot supply these in our 'core' code.
This must be implemented in one of the 'contribs'.

The alternative checksum examples in inet.c might help
to get a better checksum for your architecture without
having to revert to assembly. (Most notably for 32-bit machines)

Christiaan Simons

Hardware Designer
Axon Digital Design

http://www.axon.tv