Hi,
regarding the dirty trick I must admit I fear that it might cause a
glitch thats right. I put it in eitherway as a proof of concept and
running performance tests for evaluation of what might be possible.
Since its a thesis i thought of investigating the delay and the impact
on the performance. For actual use it shouldn't be in the code!
Since I am messing with the TCP timer I suppose that it can cause
earlier/unwanted retransmissions and connection timeouts. For my
application both doesn't pose to much of a threat at this point.
Regarding the suggest function if i understand it right i just set it up
within a callback function and if the
sys_check_timeouts();
function is called and the localtime compared to the time when i set it
up exceeds the intervall the function will be called. On that matter is
it possible to assign 0 as intervall value so it will be called with the
next sys_check_timeouts() ?
Also I want to say thank you for all your help.
sincerly,
Norbert
Am 24.09.2016 um 14:58 schrieb Noam Weissman:
Hi,
Doing some "dirty" trick will not help but cause other problems. IwIP
can back-fire and
you will get unpredictable results. Problems that can be difficult to
find.
sys_timeout is an LwIP function that runs inside the context of LwIP.
Time interval is in milliseconds.
That means that if you set it to 100ms it will call your function
(only once) when time elapses.
So instead of using the poll call back that is triggered at best every
0.5 seconds ... you can set your
own timeout function that will handle some house keeping at a faster
rate. Do remember that if you
need it to periodically do something you need to set it again and
again... until you finish the process.
BR,
Noam.
------------------------------------------------------------------------
*From:* lwip-users <[email protected]> on
behalf of Norbert Kleber <[email protected]>
*Sent:* Saturday, September 24, 2016 11:20 AM
*To:* [email protected]
*Subject:* Re: [lwip-users] prioritizing of active connections
Hi Noam,
thank you for your suggestion. I guess I will start with an OS for the
next project. For this one it's allready to late I am afraid (thesis
due date next month). I didn't fully understand the explanation in the
wiki regarding the sys_timeout(TMR_INTERVAL, function , NULL);
function. Which timer triggers this function and how can i calculate
the exact timing of the sys_timeout?
For now i found an quick and dirty approach which i can't recommand to
anyone. I just call 2x tcp_tmr() directly after my computing work is
done. This improves my performance. Where i needed 36 seconds for one
run I now only need 16 seconds.
sincerly,
Norbert
Am 23.09.2016 um 18:30 schrieb Noam Weissman:
Hi Norbert,
First of all I would suggest changing your design and use an OS. I am
running FreeRTOS
on STM micro's for 6 years now and I do not see myself doing it any
other way.
The STM32F4 is a strong micro with sufficient power to do much more
then you do now.
If you run an OS there will be a small overhead but your system
design will be much simpler
to menage.
If you use Socket API you can send data outside of the LwIP context.
If you use RAW API
you cannot send data from outside of the LwIP context and must take
that into consideration:
First option protect the code that is called from outside of the LwIP
context. Either by using a
critical section (OS).... or using the poll call back.... or
triggering LwIP own system_timer call-back:
sys_timeout(TMR_INTERVAL, function , NULL);
The above is an LwIP internal timer handling. You pass the function
you want (see prototype)
with or without parameters and it will be triggered when time expires.
BR,
Noam.
------------------------------------------------------------------------
*From:* lwip-users <[email protected]> on
behalf of Norbert Kleber <[email protected]>
*Sent:* Friday, September 23, 2016 6:58 PM
*To:* [email protected]
*Subject:* [lwip-users] prioritizing of active connections
Hi evereyone,
I got some questions again.
I am using the lwIP on a STM32F4 mikrocontroller without OS. A client
will connect to the stack at two ports for transmission. First port will
be used for controlsignals and second for datatransmission. The whole
System works sequentially.
Firstly 1 package will be received on the ctrl connection afterwards we
receive many packages on the dataconnection. Now I was wondering that
the stack acknowlegded all data packages before he acknowledges the ctrl
package. Due to the operation of the µC I can tell that he received the
package right away and ofcause i use the acknowledgement function in the
receive function. But somehow it is severly delayed approx. 200ms but
the later received data packages all get acknowledged right away.
Does the stack some prioritizing between open connections? Or is it due
to the Ctrl Package being quite short?
Also I am doing some computational work outside of the callback
functions and want to transmit some of the results asap over the ctrl
connection. Is there a way to do that without waiting for the polling
function? Or is there a way to trigger the polling function somehow for
a instant call? Also it seemed like i can't use tcp_write if i am
outside of a callback function (i was storing the pointer to the pcb in
a global variable).
sincerly,
Norbert
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