[lwip-devel] Core locking (Tasks #6935 and #6994) + some questions

[steinarl]

Hello,

I am currently working on a design that enables strict priority
queuing (based on TOS) in the tcpip thread. My current plan is to  
introduce three more input queues and make the thread always process  
the packet with
the highest priority. I am wondering about the status of the core
locking feature, and if you intend to keep both message passing and  
core locking available in future versions. I read the discussion in  
task 6935, but couldn't access 6994.

Some other questions:

Function call VS macro, tcpip_apimsg:
This was mentioned in task 6935, but I don't understand why you have  
three of the netconn functions using tcpip_apimsg() directly, and the  
remaining ten using the macro.

Control flow in tcpip_thread:
Are any of the TCPIP_MSG_* messages sensitive to timing? If possible I  
would like to keep the internal messages at a lower priority than the  
top priority message traffic (to enable WCET analysis).

I made diagrams of function calls in UDP Rx and Tx using the  
sequential API, I would appreciate it if anyone could have a quick  
look at them and tell me if I got it right :)
http://folk.ntnu.no/steinar/lwip/Rx.png
http://folk.ntnu.no/steinar/lwip/Tx.png

I also intend to write a unit test for the tcpip_thread using check. I  
can post it later if you are interested.

Regards,
Steinar Lieng Fredriksen
Norwegian University of Science and Technology