Evaluating a Fixed-size Machine
Many critical characteristics depend on problem size
- Inherent application characteristics
- concurrency and load balance (generally improve with problem size)
- communication to computation ratio (generally improve)
- working sets and spatial locality (generally worsen and improve, resp.)
- Interactions with machine organizational parameters
- Nature of the major bottleneck: comm., imbalance, local access...
Insufficient to use a single problem size
Need to choose problem sizes appropriately
- Understanding of workloads will help