[Beowulf] DIMMnet-1 DIMM slot NIC?

Joachim Worringen joachim at ccrl-nece.de
Mon Jul 26 09:26:59 PDT 2004

Keith D. Underwood wrote:
> Now, if you want to implement something like UPC or SHMEM and you have
> all of the shared address space located on the card plugged into that
> slot (maybe not incredibly practical, but probably possible) then a DIMM
> interface may be your best bet.

Even then, you have the problem that this approach doesn't scale: a 
single memory slot can cover only a small fraction of the memory of the 
N other nodes (think of N >> 10), which requires to fall back on message 
passing again (via shared memory, in this case). And for one-sided 
communication via messsage passing, it really hurts to have no interrupts.

In contrast, the address space on the I/O bus is much larger (for PCI-X 
and PCIe).


Joachim Worringen - NEC C&C research lab St.Augustin
fon +49-2241-9252.20 - fax .99 - http://www.ccrl-nece.de

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