[etherlab-users] Jitter + Timed Out datagrams

[chg at alpenjodel.de]

> On Tue, Mar 03, 2009 at 05:19:18PM +0100, Christian Gieseler wrote:
> > As timing source i use the same sources that are given in your user
> > and mini examples.
> 
> The minimal (kernel) example uses a kernel timer, that is usually not a
> good timing source at all. The userspace example uses the setitimer()
> function to generate SIG_ALRM signals, which has the same behaviour.
> These two examples use on-board methods go create cyclic-tasks to get
> something running without great efford. They're not meant to create
> jitter-free cycles.
> 
> Do you have the possibility to try RTAI or an RT-preempt kernel?
Hello Florian,

thank you for your explanations about the timing sources. I wasn´t sure if there are any more precise alternatives to the used clock sources exept from the ons offered by a patched kernel.

Just now I am already working on setting up an RTAI patched kernel. I see that this would help with the jitter values. 
But i don´t understand how this should change something with the timed out datagrams in idle mode. And since the master module is not an RTAI module this problem probably wouldn´t change. Or do i get something wrong and by setting the rtai directory when configuring the master modules changes and gets another clocksoure if the rtai modules are loaded?

Best regards

Christian


-- 
Psssst! Schon vom neuen GMX MultiMessenger gehört? Der kann`s mit allen: http://www.gmx.net/de/go/multimessenger01