Re: [lwip-devel] Speed up lwIP

[Jonathan Larmour]

Goldschmidt Simon wrote:
> Hi all,
>
> Talking about lwIP performance on this list, I have 2 issues which
> I think could speed up lwIP (at least for me, they did):
>
> - create a #define MEMCPY(dst,src,len) (defined to memcpy(dst,src,len)
> as default) to be able to easily provide a faster memcpy than the one
> included in the C library. Especially if src or dst are not aligned,
> writing my own memcpy gave me much better performance. I could define
> memcpy to my own version, but in my opinion, that's a dirty hack.

This makes sense. Note that care may be required on when to use MEMCPY 
instead of memcpy - GCC can optimise memcpy away sometimes, particularly 
with a constant, relatively small "len". That saves a function call. Maybe 
a second macro for that case? SMEMCPY for small memcpy?

> - (only for little endian processors and spectial MACs):
> include some kind of define to tell the stack not to convert items in
> protocol headers from host to network order if the MAC can do this.
> This requires a rather advanced MAC, but still I think it's important
> that we support this in order not to slow down MACs that have
> accelerating
> features.

Perhaps you can just tell lwIP you are big-endian when you aren't? Are 
there places where endianness is tested but not for protocol headers?

OOI I've never seen such a MAC.

Jifl
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