Re: [Xenomai] Fwd: Re: Problem that the Linux scheduler is not called for some ms

["Harald Feßl" <harald.fessl@sigmatek.at>]

Hi

The linux tasks are not blocked (not all).
I think the problem is , that the linux scheduler function in the kernel 
is not called for some ms.
I have also traced the calls to the scheduler function
"static int __sched __schedule(void)"
and sometimes when the decribed problem occur this function is not 
called while no linux task are running.

Harald Fessl


> As you already recorded (f)traces, just dive deeper and check why some
> of the Linux tasks are blocked, ie. when they go to sleep, check the
> reason. And then, when they wake up again, check who woke them up and
> via which mechanism. Maybe that will provide some trace to what goes wrong.

> Jan

> --
> Siemens AG, Corporate Technology, CT RTC ITP SES-DE
> Corporate Competence Center Embedded Linux


> On 2015-09-22 16:13, Wolfgang Netbal wrote:
> >>
> >>
> >> Hi guys
> >>
> >> I have a problem that the linux scheduler is not called for some ms.
> >> The cpu load is very low.
> >>
> >> Im using a iMX6, linux kernel 3.0.42 and xenomai 2.6.2.1.
> >>
> >> I have attached a graphical task trace where you can see the task switches.
> >> The tasks with prefix X- are xenomai task, the prefix L- means linux task.
> >> In the first line you can see the tick from a fpga to start the folowing
> >> tasks, X-realtime, X-cyclic, X-Loader and X-background.
> >> The X-Cyclic task is switching to linux (L-Cyclic) in each cycle because
> >> it is calling UDP functions.
> >> Up the mark 195 ms everthing is working correct.
> >>  From the mark 195 ms up to 199 ms there is no linux task (L-) running.
> >> I have also seen that the linux scheduler function is not called from
> >> the mark 195ms to 199ms.
> >>
> >> Does anybody know what is the problem ?
> >> Are there some linux/xenomai settings to modify this behavior ?
>
>