Re: [lwip-users] Re: Lwip UDP performance

[Christiaan Simons]

address@hidden wrote on 28-03-2006
12:12:27:

> I'm using this ethernet hardware too and its sad but true, the
> device does only have 4 fixed size (receive) buffers.

Ahum, good to learn this.
The shiny Altera sales talks won't tell these nasty problems.

> Routing packets thought the stack will take much more time than, but
> if u have send-delays, u can process the packets from a buffer after
> the bursts.

Do you have an idea where lwIP spends a lot of time in your system?
If you do know about weak points in lwIP I can have a look at those.

I think the pbuf_alloc() can be a bit expensive, and when having a
lot of netifs and PCBs it can slow things down. The memcpy's
in ip_reass won't help much either. For unfragmented traffic I don't
expect any big delays.

Currently I can't pin-point truly encumbered code with regards
to unfragmented IP/UDP speed.

Speeding up the lwIP core for reading unwanted broadcast UDP
(Microsoft SMB blabla) is a bit of a priority for us.

(I don't want to disable the UDP checksumming,
it's only done for traffic that is accepted anyway)

Bye,

Christiaan Simons

Hardware Designer
Axon Digital Design

http://www.axon.tv