Re: [Gems-users] Where to start: a different memory system

[Mike Marty <mikem@xxxxxxxxxxx>]

> Sorry for my 'stupid' newbie-question, but I'm new with GEMS and the
> documentation on the web is not so comprehensive.
>
> I'd like to test a different way of connecting memory to a system. The
> memory-modules should be autonomic and manage themselves. This means,
> that access to the memory-modules is achieved through requests and answers.
>

I'm confused.  Isn't access to memory-modules (via memory controllers)
already achieved via requests and responses?

> I think I have to change the memory hierarchy and add a
> controller/requester after the Caches which generates the requests and
> sends them to controllers attached in front of the memory-modules. For
> the communication beetween these controllers another protocol is used.
>

A typical CMP protocol in GEMS implements an L1 controller, an L2
controller, and a "Directory" controller (which is really a
directory/memory controller).

In the past, I have decoupled the Directory controller to implement a
seperate controller for the "Directory" and the "Memory"

> Do you think it is possible to implement this with GEMS?

Very much

> Where should I start? What do I have to change? Where can I iplement
> these controllers and where the protocol?
>

On Friday, I plan on putting out a bugfix release that will include a new
directory protocol for Single-CMPs.  It would probably be easiest to start
with this protocol.  In fact, the memory has a seperate controller that
answers to a single "fetch" request.

--Mike