Re: [lwip-users] lwIPv1.3.0 memory

[Benoit Camus]

Hello Bill,

Here is the way i do to fine tune LwIP's memory to my application, maybe 
will it help you with you first question:

First i use the lwip statistics ( have to define SYS_STATS in lwipopts.h).
Then i stop application with debugger before and after having applied 
some loads over the system and
look at the lwip_stats structure (global variable in stats.c) to get the 
memory requirements.
Of course loads you apply must be typical ones to cover all your system 
behaviour. I do it too with a long time test.

The lwip_stats structure gives you the currently used memory ( number of 
buffers from pools or bytes in heap),
and the max used and number of errors too for each one. Semaphore and 
queue values are also interesting to look for.
This allows you to set lwipopts.h with the closest values needed by you 
application. Of course keep some margin due to
ethernet network nature.

Heap is easely identify (first one in memp tab if i remeber well).
Looking for pools is a little harder (some can be desactivated) and i 
suggest you to use preprocessor over memp.c to see the order of pools 
and make the mind link easier.

I would also be interesting if anyone using another way to tune 
lwipopts.h could tell about it.

B. Camus
> Hi,
>
> I have three questions regarding the memory definitions in lwipopts.h 
> based on lwIPv1.3.0. I wonder if some one can help me.
>
> (1) In current memory options defined as below.
>
> //#define MEM_LIBC_MALLOC 0
>
> #define MEM_ALIGNMENT 4 // default is 1
>
> #define MEM_SIZE (18 * 1024) // default is 1600, was 16KIntDefaultHandler
>
> //#define MEMP_OVERFLOW_CHECK 0
>
> #define MEMP_SANITY_CHECK 1
>
> //#define MEM_USE_POOLS 0
>
> //#define MEMP_USE_CUSTOM_POOLS 0
>
> Q1: Can I reduce the MEM_SIZE TO (12 * 1024)? Is there any risk there?
>
>
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Benoît CAMUS
Leroy Automatique Industrielle
Bd du Libre échange - 31650 Saint-Orens
Standard : 05.62.24.05.50
e-mail : address@hidden