Re: [lwip-users] performance

[K.J. Mansley]

On Wed, 2004-07-28 at 22:53, Sam Jansen wrote:
> Where lwIP doesn't shine is when the network coniditions are not so 
> perfect. It's my belief that the granularity of the timers hurts it 
> here, having to wait a minimum 500ms for a retransmit timeout can be 
> seriously detrimental to TCP performance.

That is, I think, something which is common to all (most?) TCPs, not
just lwIP.  It's also something that would be easy to change.  I agree
that, if TCP was being specified now, it would be unlikely that the
retransmit timer would have such a long timeout.

> I'm unsure exactly how well it copes with a somewhat congested network; 
> but as far as I can tell it lacks the sophistication of the congestion 
> control mechanisms present in modern OSs today (FreeBSD/Linux/OpenBSD 
> are all I have tested against).

Apart from the changes that are in progress at the moment, thanks to
suggestions from you and Karl Jeacle, is there something we're not doing
that other stacks are, or is it just that our implementation of the
algorithms is less good?

It seems you're able to compare against a number of other stacks, which
is something we've not done a great deal in the past, and is obviously a
good idea.  If you're able to make any other suggestions of specific
areas for improvement, I'm sure we'd be interested to hear them.

Thanks

Kieran