[riot-users] UDP Packet Register

Peter Kietzmann peter.kietzmann at haw-hamburg.de
Mon Nov 5 15:25:36 CET 2018


Hi,

gnrc_netreg_register() registers a thread in the registry "netreg"
indicating (i) the packet type (protocol) and (ii) an additional
de-multiplex context [1] (for example a UDP port) it wants to receive.

An additional RTT by the factor three seems extremely huge to me. Did
you measure this between boards under the same conditions, multiple
times? However, I guess a certain overhead is introduced by the dispatch
mechanism. Please have a more detailed look at the implementation of
gnrc_netapi_dispatch() [2].

Best
Peter


[1]
https://riot-os.org/api/group__net__gnrc__netreg.html#ga1a6359efa13b3bfed70af55deacde7ae
[2]
https://github.com/RIOT-OS/RIOT/blob/master/sys/net/gnrc/netapi/gnrc_netapi.c#L94


Am 01.11.18 um 23:27 schrieb Navneet Pandey:
> Hello,
> 
>  
> 
> What is the difference between the following ways of subscribing to
> receive a UDP Packet.
> 
>  
> 
> /* initialize and register pktdump to print received packets */
> 
> gnrc_netreg_entry_t server = GNRC_NETREG_ENTRY_INIT_PID(8888,
> sched_active_pid);
> 
> gnrc_netreg_register(GNRC_NETTYPE_UDP, &server);
> 
>  
> 
> vs
> 
>  
> 
> /* initialize and register pktdump to print received packets */
> 
> gnrc_netreg_entry_t server =
> GNRC_NETREG_ENTRY_INIT_PID(GNRC_NETREG_DEMUX_CTX_ALL,
> 
>                                 sched_active_pid);
> 
> gnrc_netreg_register(GNRC_NETTYPE_UDP, &server);
> 
>  
> 
> I was curious because, the value of ‘Round Trip Time’ triples If I use
> the 2nd way (bottom one).
> 
>  
> 
> Thank you
> 
>  
> 
> Regards,
> 
> Navneet Pandey
> 
>  
> 
> 
> _______________________________________________
> users mailing list
> users at riot-os.org
> https://lists.riot-os.org/mailman/listinfo/users
> 

-- 
Peter Kietzmann

Hamburg University of Applied Sciences
Dept. Informatik, Internet Technologies Group
Berliner Tor 7, 20099 Hamburg, Germany
Fon: +49-40-42875-8426
Web: http://www.haw-hamburg.de/inet


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