Re:Re: [lwip-users] How to optimise

[Chris WIlliams]

Paul,

Interesting to see someone else using H8. I am using H8/2350 with lots
of fast memory, so I am looking for optimisations where RAM is no
problem. I suspect that my major bottleneck is the TCP window. This is
how much data can be sent before an acknowledge is received. I think my
system is a little slow to send ACK's, so I think I need a bigger
window. 

My measure of speed is running as an FTP server. My windows PC program
tells me the data transfer rate when I send or receive data. Its a crude
measure but it is a start.

I have tried using the fast internal RAM on the processor. I think you
should put data structures into it, possibly buffers, but I don't think
that you get much benefit putting code there. Code will be internally
'cashed', so I don't think you will see as much benefit as you would
think.

I am using an SMC91C96 Ethernet card of my own design. This is only
10Mb, but with little processors like the H8 running at 20Mhz, there was
no need for the extra complexity of 100Mb. I wrote the driver for my
self based on one I found for Linux.

I also have a packet driver interface to lwip. This allows me to use a
PC running DOS to test lwip code.

Chris
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