[lwip-users] AVR32 Software Framework EVK1100 and LwIP operates too slow

[Delta Control - Bernd Uttich]

Dear LwIP users,

 

I currently work on a project were LwIP is ported to AVR32 control panel. I recognized that any time a packet is transmitted from

web server to host PC, it takes ~200ms until an ack is sent back from windows site.

This makes communication quite slow – I measured about 5kB/s.

After reading several mails in this form, I tried out to transmit half of segment size. Modification looks as follows:

   src\SOFTWARE_FRAMEWORK\SERVICES\LWIP\lwip-1.3.0\src\core\tcp.c

   //increase speed:

   //mss_s = outif->mtu - IP_HLEN - TCP_HLEN; // Test Bernie

   mss_s = outif->mtu/2 - IP_HLEN - TCP_HLEN; // Windows ack delay Timer would not start !!

 

I assume this is time windows ack’s single packets if no sliding Window algorithm would work on AVR32 site?

I tried to set flag TF_NODELAY in LwIP but it was not able for me to switch of windows delayed ack’s.

Do you have a recommendation for me, where in AVR32 Software Framework to implement

sock->conn->pcb.tcp->flags |= TF_NODELAY;

correctly?

Transmitting half segment size is just a fast way if I am correct here to lie to windows that each time last packet

(with smaller content than segment size) is transmitted. Loading a website now gets much faster than without this

workaround, but I assume there is other professional solution which I have not found so far..

Can you help me here?

 

Best Regards,

 

Bernd