Re: Multi-core and memory

On May 22, 12:23=A0am, "Chris Thomasson" <cris...@[EMAIL PROTECTED]
> wrote:
> "Rui Pedro Mendes Salgueiro" <r...@[EMAIL PROTECTED]
> wrote in
messagenews=
:g0v24v$f8o$1@[EMAIL PROTECTED]
>
> > Hello
>
> > Would it make sense to have multiple memory interfaces in multi-core
CPU=
s
> > ?
> > Have Intel or AMD announced plans to have such a thing ?
>
> [...]
>
> I have always wondered why a multi-core CPU could not be
> __directly_integrated__ into a memory card. IMHO, a 2GB mem-card should
be=

> able to physically integrate with one or two multi-core CPU's. The
memory
> which resides on the same card as the CPU(s) could be accessed using a
cac=
he
> coherent shared memory model. If one card needs to communicate with
anothe=
r,
> then a message-passing interface would be utilized. Think of a single
> desktop sized system that has 8 2GB cards with two 64-core CPU's
per-card.=

> That's 16GB of total distributed memory running on 1024 cores...
>
> Does anybody know of any experimental projects that are trying to
accompli=
sh
> something even vaguely similar?
>
> Of course, the chip vendor would need to be the memory vendor as well...
> Humm...
>
> IMVHO, drastically reducing the physical distance between the chip and
its=

> local memory can be very im****tant factor wrt scalability concerns. It
> should be ideal to merge the chip and a couple of GB of memory into a
sing=
le
> unit.
>
> Intra-CPU to local memory =A0communication would use shared memory, and
> inter-CPU and remote memory communication would use message passing. It
> seems the scheme could be made to work... What am I missing?

Heat disipation. One could, in principle, design a DRAM daughtercard
that had an Opteron/Barcelona socket in the middle, ranks of DRAMs to
the left and right, and HT links through the pins. Dealing with the
100Watts of power at the center would make the spacing between
daughter cards pretty large, and cooling a little on the difficult
side.

BUT it is possible today, if you wanted to try and make a go of it.