Re: [lwip-users] problems with LWIP on Xilinx ML403

[Kieran Mansley]

On Mon, 2007-10-01 at 12:46 -0700, Mike Caplinger wrote:
> I've been trying to do large bulk data transfers using the sockets API 
> on an ML403 board using the version of LWIP bundled with EDK 8.2i.  I 
> won't bore you with all the total stalls of LWIP I've experienced, but I 
> have noticed that there seems to be a huge bug in the Xilinx 
> implementation of sys_arch.  The function sys_arch_sem_wait is supposed 
> to return the amount of time it had to wait to get the semaphore, or 
> SYS_ARCH_TIMEOUT if it failed to get it.  But the v2pro port version in 
> EDK 8.2i simply returns the timeout immediately if it got the semaphore, 
> regardless how long it had to wait, if at all.  This causes the TCP 
> thread, which is using a 250 msec timeout handler to call tcp_tmr,  to 
> go completely nuts during a transfer, since tcp_tmr ends up getting 
> called at extremely high rates.  Retransmits and timeouts happen too 
> fast, RTO is completely misestimated (I've seen it stuck up at 32767) etc.

As this is a bug in a port rather than lwIP itself I think you'll have
to contact whoever distributes your EDK 8.2i and ask them to fix it.
This is code that is beyond our control.

Thanks

Kieran