Posts: 75
Joined: Sat Mar 23, 2013 5:21 am

Xenomai: heavy ethernet load , lead to jitter

Sat Mar 23, 2013 5:59 am

using a 3.5.7 Kernel and Xenomai 2.6.1patch
facing the following problems;
if there is a high load on ethernet communication, the jitter increase,
we see every. I would say 10s a peak of almost 8ms-10ms or even more,
nomally the jitter for the cyclic task is 40us-60s in worst case and preatty stable, but with high ethernet
load unaceptable peaks occure.

Is this caused by the usb connection of the smcxxx network implementation?
tried to play around with vm.min_free_kbytes = 32768 , this seems to improve it slightly
but it is no solution.
Has anyone an idea how to solve this?
I'm not very familiar with that, therefore some questions is there an option to use the smsc95xx
as rtnet interface?

thanks for your suggestions

Posts: 42
Joined: Thu Nov 29, 2012 8:55 pm
Contact: Website

Re: Xenomai: heavy ethernet load , lead to jitter

Thu Mar 28, 2013 8:51 am


I'm experiencing the same problem... If I am flooding my RPi with Xenomai Kernel with a very high number of machines (for exemple 4 machines which make ping -qf MyXenomaiRPi), I get a latency which can raise up to 30 ms against 50 µs (which seems to be a typical latency with Xenomai) when I have only 2 flooding machines.

I use this tutorial http://www.blaess.fr/christophe/2013/02 ... avec-rtdm/ (in french sorry), with kernel 3.5.7 and Xenomai

Thank if anybody has already investigate this problem !
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