Re: [lwip-users] message api bug and throughput problem

[K.J. Mansley]

On Mon, 2004-03-22 at 11:27, address@hidden wrote:
> Hi all!
> 
> I have two problems:
> 
>   1.  Possible mailbox bug in the message api
>   2.  Throughput problem

I'm not sure about number 1, so I'll jump straight to number 2:

> 
> 2. Throughput problem
> ---------------------
> 
> I am running lwIP on a PowerPC 440GP at 400MHz with uCOS-II. 
> For our application I need a throughput of at least 35 MBit/s. 
> The throughput I get is only 7.6 kB/s per connection. I can 
> open multiple connections each running at 7.6 kB/s while the
>  PowerPC is still lazy at 3% CPU usage. Has anybody observed
>  the same behaviour? I have tried to increase the tcp timer 
> rate but without luck. I am using chargen.c from the lwIP 
> contribution package for my test

If you can achieve the required throughput using multiple connections,
it sounds like the window size or the send buffer size of each
connection is the limiting factor.  Try increasing the settings for
these in lwipopts.h  If you know the round trip time of your network you
can calculate the theoretical values needed for the throughput you
require.

Kieran