Re: [Gems-users] convert MOSI_SMP_bcast to MOSI_CMP_bcast

[Mike Marty <mikem@xxxxxxxxxxx>]

>
> I would like to use the bus based snooping protocol for my project in CMP
> system.
> I saw the list of protocols supported by the GEMS doesn't contain any bus
> based snooping protocol for CMP systems.
>
> I would like to change the current MOSI_SMP_bcast to MOSI_CMP_bcast
> protocol, but as I dont know the SLICC in detail and how should I change the
> network configuration used.
> So I am requesting to this group to help me out to create this new protocol.
> I have following questions:
>
> 1) Can I simply change the network topology in MOSI_SMP_bcast protocol to
> look like MOSI_CMP_bcast?
>

Yes, if you are ok with private L1/L2 caches in the same controller.

MOSI_SMP_bcast also creates a DirectoryController for every processor.
You will want to change this.

> 2) Why is directory used in MOSI_SMP_bcast? as it is a bus based snooping
> protocol, it shouldn't require any directory.
>

Ruby does *not* implement shared lines.  Thus a "directory" holds an owner
bit to determine if memory shoudl respond with data.

Ruby doesn't have a true bus interconnect.  It uses an ordered
hierarchical switch.

--Mike