System Software Performance scales nearly perfectly with the number of processors to the full size of the computer (~20,000 processors). This means that System Software time (overhead) remains nearly constant with the size of the system or scales at most logarithmically with the system size.
- Full re-boot time scales logarithmically with the system size.
- Job loading is logarithmic with the number of processors.
- Parallel I/O performance doesn’t depend on how many PEs are doing I/O
- Communication Network software must be scalable.
No connection-based protocols.
Message buffer space independent of # of processors.
Compute node OS gets out of the way of the application.