 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Bus
inevitably becomes a bottleneck when many processors are
|
|
|
used
|
|
|
|
Use
a more general interconnection network
|
|
|
 |
|
|
|
|
|
|
So
snooping does not work
|
|
|
|
|
|
|
|
|
|
DRAM
memory is also distributed
|
|
 |
|
|
|
|
|
|
Each
node allocates space from local DRAM
|
|
|
|
|
|
|
|
|
|
Copies
of remote data are made in cache
|
|
|
|
|
|
|
|
|
|
Major
design issues:
|
|
|
|
|
|
|
|
|
How
to find and represent the “directory" of
each line?
|
|
|
|
|
|
|
|
|
|
How
to find a copy of a line?
|
|
|
|
|
|
|
|
|
|
As
a case study, we will look at S3.MP (Sun's Scalable Shared
|
|
|
|
|
memory
Multi-Processor, a CC-NUMA (cache-coherent non-
|
|
|
uniform
memory access) architecture
|
|