Re: [Xenomai-help] Get ready queue

[Philippe Gerum <rpm@xenomai.org>]

On Fri, 2009-07-17 at 08:18 -0300, Thiago Lima wrote:
> I am doing an schedulability test of real time processes in Xenomai.
> So that, when a new task is started in system, i need to get all
> threads from system, including the new one and make a test to decide
> if this workset is schedulable.
> 
> I have a linux kernel module with a hook that is called whenever a
> task is started. Besides, i have to apply a patch to xenomai kernel in
> order to allow the hooks calling when a user space task is started.

You are likely using an outdated Xenomai core. 2.4.8 fires the START
callout for userland threads as well.

> 
> My question is: how can i get all ready xenomai tasks ? Because i need
> to get the amount of threads to do this test.
> 

Regarding the Xenomai 2.4 core: include/nucleus/pod.h, follow the readyq
member from the struct xnsched type.

This said, the scheduler innards were heavily rewritten in 2.5, to
provide scheduling classes and more policies than RR+FIFO (e.g. time
partitioning and POSIX sporadic server). So what you would measure for
2.4 may not be relevant with 2.5.

> Sorry for my last email. I have not so much time to write and it was
> vague.
> 
> att,
> 
> Thiago.
> 
> On Wed, Jun 10, 2009 at 4:59 PM, Gilles Chanteperdrix
> <gilles.chanteperdrix@xenomai.org> wrote:
>         Thiago Lima wrote:
>         > Sorry, i didnt understand you answer.
>         
>         
>         The question was vague, so was the answer.
>         
>         > I get the global queue doing this:
>         >
>         > threads = &pod->threadq;    // GLOBAL QUEUE
>         > holder = getheadq(&nkpod->threadq); //HEAD NODE
>         
>         
>         These are internal data, you are not supposed to access them
>         that way.
>         Besides threadq is not the ready queue. And with the recent
>         advent of
>         the scheduler classes, you could not do the same modification
>         for the
>         latest version of Xenomai. In short, it is a bad idea, really.
>         
>         If you explained us what you are trying to do (and not how you
>         are
>         trying to do it), maybe we could help. Chances are that you
>         can do what
>         you do without changing Xenomai core, simply using hooks for
>         instance.
>         
>         --
>                                                    Gilles.
> 
> 
> 
> -- 
> Thiago Lima Silva
> Graduando - Ciência da Computação UFBA
> Registered Linux user #466887
> 
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-- 
Philippe.