Planned SMP Improvements

[Darshit Shah]

On 27 January 2016 at 10:54, Sebastian Huber
<sebastian.huber at embedded-brains.de> wrote:
> Hello,
>
> I added three tickets that will lead to a major improvement of the SMP
> capabilities of RTEMS in case we are able to implement them:
>
> New watchdog handler implementation
> https://devel.rtems.org/ticket/2554
>
> Eliminate the Giant lock
> https://devel.rtems.org/ticket/2555
>
> Implement the O(m) Independence-Preserving Protocol (OMIP)
> https://devel.rtems.org/ticket/2556
>
> It takes several weeks of work to implement them and it will lead to major
> changes in core operating system components. Besides the increased
> complexity in the locking protocols I don't expect negative impact for the
> uni-processor configurations. Please review these tickets. I would be happy
> about feedback.
>
These are great write ups, as Gedare as already mentioned. Easy to
follow and reason even for someone pretty new to the entire project. I
agree that the Red-Black Tree approach for the new watchdog handler is
a better idea because of its predictable performance guarantees.

> Maybe we can implement
>
> Improve the SMP scheduler with arbitrary processor affinity support
> https://devel.rtems.org/ticket/2510
>
> as part of this years GSoC.
>
I've already mentioned that I'd be interested in picking this up as a
potential project. However, the entire implementation may not be
possible in a single summer. It is rather complex, and while a naive
implementation may be possible to write, we would want something more
efficient. I'm hoping for some pointers on where I should start
looking for a better understanding of the codebase.

However, apart from this, even Eliminating the Giant Lock and
Implementing OMIP could potentially be GSoC projects. These may not be
extremely large changes, and you could probably finish them in a
couple of weeks, but they would take someone new much longer.
Reasoning about the new code will not be trivial.

> Once this is done we have a state-of-the-art real-time operating system for
> SMP systems in the single-process/multi-thread environment from my point of
> view.
>
> --
> Sebastian Huber, embedded brains GmbH
>
> Address : Dornierstr. 4, D-82178 Puchheim, Germany
> Phone   : +49 89 189 47 41-16
> Fax     : +49 89 189 47 41-09
> E-Mail  : sebastian.huber at embedded-brains.de
> PGP     : Public key available on request.
>
> Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG.
>



-- 
Thanking You,
Darshit Shah