(Not examinable for this course.)
The following plot has two salient features:
Firstly, a high-performance CPU contains a lot of ancillary logic to achieve this performance (reorder buffers etc.).
Two smaller CPUs give twice the performance of a single smaller CPU at exactly twice the power.
Secondly, all three configurations illustrate performance can be changed as V and F parameters are varied, but the performance gain requires super-linear power use.
ARM has its big.LITTLE system where CPU state is shunted between different core designs as the measured load varies. »big.LITTLE ProcessingBut it is better to write a parallel program if you can and then use multiple simple cores.
|23: (C) 2008-13, DJ Greaves, University of Cambridge, Computer Laboratory.|