Re: [lwip-users] ACK missing after SYN, strange high Ack Num

[Jochen Strohbeck]

Looks to me this is a performance issue.

I never noticed such a problem over the last years. The problem seem to
arise since http requests are sent from a more powerful (Intel) CPU.

According to wireshark my 3 years old (Windows) laptop sends out 500
http packets/s, a newer laptop (Linux) sends out ca. 2500/s. I can lower
the rate to 2000/s by configuring the network to 10Mbit/s, which is
obviously still too high.

Guess the GMAC driver, tcp processing or http server gets into an
overload situation. I already made some patches in the GMAC driver and
lwip interface to improve processing speed. But now I'm stuck here.

What kind of problem may force lwip to send ACK instead of SYN+ACK?

I'm running lwip 1.4.1, FreeRtos 10 on SAME70 at 300MHz.

Do you think this platform is not powerful enough to handle such high
ethernet traffic?

Do you think that upgrading to 2.x will improve anything e.g.
performance issues?

Are there any lwip or host parameters to make the TCP/IP timing more
tolerant?