Emerging Technologies of Computation

Montek Singh

COMP790-084Oct 6, 2011

Today’s topics:◦ approximate arithmetic◦ simple applications

Next time:◦ more applications◦ architectures and design tools◦ challenges and benefits◦ open questions

Today: Probabilistic Design

Supply reduced voltage to adder gates◦ fine-grain: each stage receives own voltage◦ coarse-grain: use binning

Probabilistic arithmetic

Error induced:

Energy consumed:

Probabilistic arithmetic

Voltage selection

◦ fine-grain: each stage receives own voltage

◦ coarse-grain: use binning

Probabilistic arithmetic

Geometric model for voltage assignment◦ higher order bit receives progressively higher

voltage

Probabilistic arithmetic

Energy-correctness tradeoff

Probabilistic arithmetic

Energy-correctness tradeoff example

Probabilistic arithmetic

Lower voltage causes clock deadline to be missed◦ some of the longer carry chains cannot complete!

Delay-Induced Approximation

Delay-Induced Approximation

Example: DFT

Delay-Induced Approximation

Example: DFT

Delay-Induced Approximation