Shared-Memory Machines -- Notes
Interconnection network shown here is actually for the BBN Butterfly, but C-90 is in the same spirit.
These machines share data by direct access.
- Potentially conflicting accesses must be protected by synchronization.
- Simultaneous access to the same memory bank will cause contention, degrading performance.
- Some access patterns will collide in the network (or bus), causing contention.
- Many machines have caches at the processors.
- All these features make it profitable to have each processor concentrate on one area of memory that others access infrequently.