SIMD Is Simply Too Rigid
SIMD architectures have two advantages over MIMD architectures
- There is no program memory -- smaller footprint
- It is possible to synchronize very fast ... like on the next instruction
SIMD has liabilities, too ...
- Performance: if aɬ then ... else ...
- Processor model is the virtual processor model, and though there are more processors than on a typical MIMD machine there is never 1pt/proc
- Ancillary: instr. distribution limits clock, hard to share, single pt of failure, etc