Global Shared Memory and SCI/Dolphin

Greg Lindahl lindahl at
Thu Jul 17 17:13:01 EDT 2003

On Thu, Jul 17, 2003 at 12:15:56PM +0100, Daniel Kidger wrote:

> The Quadrics Interconnect also does hardware RDMA, and yes a significant
> percentage of people do use Global Shared Memory programming models rather
> than message passing.
> In fact I thought all four of SCALI/Quadrics/Myrinet/Infiniband could do
> RDMA ??

There's a terminology problem here: Some people mean cache-coherent
shared memory, like that on an SGI Origin.

Another term for non-cache-coherent but globally addressable and
accessible memory is SALC: Shared address, local consistency.

And yes, all 4 of Scali/Quadrics/Myrinet/Infiniband support the
non-cache-coherent kind of shared memory. Programming models in this
area are:

  * UPC: Unified Parallel C
  * CoArray Fortran
  * MPI-2 one-sided operations
  * Global Arrays from PNL
  * The Cray SHMEM library

-- greg

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