[Adeos-main] a few questions

[Adeos-main] a few questions

[Der Herr Hofrat]

HI !

 reading my wai into adeos - so pleas excuse if these question are stupid..
 after reading the docs on adeos.org and a few comments in the 
 RTAI mailng list a few questions arose:

 1) Is ther and example of running multiple domains under adeos (exept for RTAI which is not completly independant (?) of the root domain - atleast it does not seem posible to run multiple instances of RTAI in paralell ?
 Has anybody ran multiple Linux or other OS'under ADEOS
 and are there any docs about this ??

 2) for shared resources - Network cards etc. - the
    Root domain driver is responsible (or a root-domain-process) for
    dispatching the domain specific data (i.e. a ip-packet for a 
    specific domain)a

thanks fro any clarification
hofrat 

[Adeos-main] a few questions

[Philippe Gerum]

Hi,

Der Herr Hofrat writes:
 > 
 > HI !
 > 
 >  reading my wai into adeos - so pleas excuse if these question are stupid..
 >  after reading the docs on adeos.org and a few comments in the 
 >  RTAI mailng list a few questions arose:
 > 
 >  1) Is ther and example of running multiple domains under adeos

You can find a trivial code which loads a domain module intercepting
the timer IRQ here:
http://savannah.nongnu.org/cgi-bin/viewcvs/adeos/adeos/platforms/linux/examples/simple/.

For a more complex implementation, there's something in RTAI's ongoing
magma development branch called the "Xenomai skins" which runs three
concurrent domains:

o the RTAI domain (priority=200)
o the Xenomai domain (priority=150)
o the (root) Linux domain (priority=100)

RTAI runs real-time tasks with memory protection created by RTOS
emulators mounted by Xenomai, and the Xenomai domain shields
interrupts from the Linux domain when needed to guarantee determinism.
IOW, the event flow goes this way:
[IRQ/traps] ==> RTAI -> Xenomai -> Linux, each of them being able to
decide whether the next domain down the pipeline should be passed the
event or not.

 > (exept for RTAI which is not completly independant (?) of the root domain - atleast it does not seem posible to run multiple instances of RTAI in paralell ?

In fact, it is indeed logically independent once the root domain has
loaded the RTAI one. One could take the Adeos-based HAL, only change
its domain priority and load it as-is, concurrently to the original
RTAI domain for running kernel-based tasks.  Have a look to
arch/i386/arti.c from the RTAI "etna" or stromboli" branches, or
rtai-core/arch/i386/hal/arti.c from the "magma" branch.

 >  Has anybody ran multiple Linux or other OS'under ADEOS
 >  and are there any docs about this ??
 >
 >  2) for shared resources - Network cards etc. - the
 >     Root domain driver is responsible (or a root-domain-process) for
 >     dispatching the domain specific data (i.e. a ip-packet for a 
 >     specific domain)a
 > 

Running multiple concurrent Linux instances using Adeos on a single
box would indeed require to decide about which instance/domain
controls which set of hardware resources and system software, and use
some kind of virtual relay to honor inter-domain requests. But as of
now, there has not been much work on this application of the Adeos
scheme (none that I know of to be precise).

Philippe.

Re: [Adeos-main] a few questions

[Der Herr Hofrat]

> 
> Hi,
> 
> Der Herr Hofrat writes:
>  > 
>  > HI !
>  > 
>  >  reading my wai into adeos - so pleas excuse if these question are stupid..
>  >  after reading the docs on adeos.org and a few comments in the 
>  >  RTAI mailng list a few questions arose:
>  > 
>  >  1) Is ther and example of running multiple domains under adeos
> 
> You can find a trivial code which loads a domain module intercepting
> the timer IRQ here:
> http://savannah.nongnu.org/cgi-bin/viewcvs/adeos/adeos/platforms/linux/examples/simple/.
> 
> For a more complex implementation, there's something in RTAI's ongoing
> magma development branch called the "Xenomai skins" which runs three
> concurrent domains:
> 
> o the RTAI domain (priority=200)
> o the Xenomai domain (priority=150)
> o the (root) Linux domain (priority=100)
> 
> RTAI runs real-time tasks with memory protection created by RTOS
> emulators mounted by Xenomai, and the Xenomai domain shields
> interrupts from the Linux domain when needed to guarantee determinism.
> IOW, the event flow goes this way:
> [IRQ/traps] ==> RTAI -> Xenomai -> Linux, each of them being able to
> decide whether the next domain down the pipeline should be passed the
> event or not.
>

anything on the web about this ??
 
>  > (exept for RTAI which is not completly independant (?) of the root domain - atleast it does not seem posible to run multiple instances of RTAI in paralell ?
> 
> In fact, it is indeed logically independent once the root domain has
> loaded the RTAI one. One could take the Adeos-based HAL, only change
> its domain priority and load it as-is, concurrently to the original
> RTAI domain for running kernel-based tasks.  Have a look to
> arch/i386/arti.c from the RTAI "etna" or stromboli" branches, or
> rtai-core/arch/i386/hal/arti.c from the "magma" branch.
> 
>  >  Has anybody ran multiple Linux or other OS'under ADEOS
>  >  and are there any docs about this ??
>  >
>  >  2) for shared resources - Network cards etc. - the
>  >     Root domain driver is responsible (or a root-domain-process) for
>  >     dispatching the domain specific data (i.e. a ip-packet for a 
>  >     specific domain)a
>  > 
> 
> Running multiple concurrent Linux instances using Adeos on a single
> box would indeed require to decide about which instance/domain
> controls which set of hardware resources and system software, and use
> some kind of virtual relay to honor inter-domain requests. But as of
> now, there has not been much work on this application of the Adeos
> scheme (none that I know of to be precise).
>
thanks for the clarification - I'll try to 
play with this to find out what I don't understand again ;) 

thx !
hofrat

ps.: Any presentations on such issues planed/intended fro the
 5th Real Time Linux Workshop ??

Re: [Adeos-main] a few questions

[Karim Yaghmour]

Philippe has already answered the other issues. I have just one thing
to add about what's below:

Der Herr Hofrat wrote:
>  Has anybody ran multiple Linux or other OS'under ADEOS
>  and are there any docs about this ??

No one has yet run multiple Linux instances on Adeos, but there is doc
about this. Have a look at the "A Practical Approach to Linux Clusters on
SMP hardware" whitepaper I published close to a year ago:
http://www.opersys.com/adeos/index.html
it discusses the issue quite thoroughly.

Karim

-- 
Author, Speaker, Developer, Consultant
Pushing Embedded and Real-Time Linux Systems Beyond the Limits
http://www.opersys.com || karim@domain.hid || 514-812-4145

Re: [Adeos-main] a few questions

[Philippe Gerum]

Der Herr Hofrat wrote:
 > 
 > ps.: Any presentations on such issues planed/intended fro the
 >  5th Real Time Linux Workshop ??
 > 

Not AFAIC, my schedule is hectic enough :o/

Philippe.