RE: [lwip-users] SOCK_RAW

[Zschocke, Florian]

Andreas Zippel wrote on Wednesday, February 25, 2004 12:37 PM:

>       can you tell me where i can speed up lwip as you do ?

Unfortunately that is very dependant on the rest of the system that you use
lwIP in. The sockets interface of lwIP relies heavily on message passing
between seperate threads to synchonize the sending and receiving of packets.
This can slow down operation considerately. Kieran has written a good paper
on this.

One of the things that we did was to skip the message passing when receiving
UDP messages and instead queue a packet to a PCB and call the recv callback
directly, deqeueung it again in the same task context. The other was to
implement zero-copy send and receive as special socket options, preventing
copying data on send() or receive(). Both speedups are only possible due to
the architecture of the rest of the system that we use lwIP in. So I'm
afraid it won't apply to your environment and you will have to look for
possible optimizations that fit in with the rest of your system yourself.
Sorry.

Florian