Re: [Xenomai] Linux scheduling is hijacked from xenomai scheduling

[Philippe Gerum <rpm@xenomai.org>]

On 01/27/2015 10:56 AM, Luca Galvagno wrote:
> Hi to all,
> we are using kernel 2.6.34 with the corresponding ADEOS patch

Which Xenomai release?

> (2.6.34-powerpc-2.10-03.patch ) and Xenomai on a PowerPC MPC5200b.

4 years old kernel and pipeline patch, don't expect much feedback on
this configuration.

> We are facing on a strange behavior when mixing Linux SysCalls with
> Xenomai tasks . The effect of the above mix is that the "pure" (without
> linux syscall) xenomai task continues to run , the remaining "mixed"
> task (for example we have one with a posix socket server) and moreover
> the linux os itself are not scheduled anymore. Specifically, to test
> this behavior, we connected an oscilloscope to a cpu pin , the result is
> that the xenomai task is moving the pin up and down (as it was
> programmed) but the linux machine is neither accessible via ping or via
> SSH.
> 
> Do you have some suggestions, or some tests we can do ?

Xenomai starving the regular kernel from CPU cycles until all the
pending real-time duties have been carried out is the basic idea behind
the dual kernel design, this is nothing strange.

Now the question is: why does your real-time code seem to never complete
its work loop, and there never leaves some CPU time to linux?

-- 
Philippe.