1. Overview Motivation (Kevin) Thermal issues (Kevin)
Power modeling (David)
Thermal management (David)
Optimal DTM (Lev)
Clustering (Antonio)
Power distribution (David)
What current chips do (Lev)
HotSpot and sensors (Kevin)

2. Industry Trends Everyone knows… Many of us know… Few of us know…
Transistor counts are increasing
Clock frequencies are increasing
Voltage levels are decreasing
Many of us know…
Temperature regulation will become difficult
Few of us know…
Power delivery may be another big problem
The next several slides are courtesy of Russ Joseph, Princeton University

3. Power Supply Overview

4. Power Delivery Trends Driving Trends  V Supply Voltage Z = V/ I
 I Transient Current
Key Relationship
Z = V/ I
Resulting Trends
Z Supply Impedance
$ Power Supply Cost

5. Packaging Parallels
Some interesting parallels between temperature and voltage regulation.
Temperature
Voltage
Static
Better materials
Fancy Heatsink with huge fins
Fans
Many PWR/GND pins
Decaps (In-package and On-die)
Dynamic
Dynamic Thermal Management
Active Decaps
µArch Voltage Control

6. Modeling Power Delivery
Complicated Model
Second Order Model

7. Simulating Power Delivery
Wattch produces current waveform
Impulse response of supply network
Convolution of the two yields voltage waveform

8. Motivating Voltage Control
Observations
Static (electrical component) voltage regulation will become prohibitively expensive.
Protects against a rarely encountered worst case.
Proposition
Dynamic voltage regulation can avoid adding discrete components, saving cost.
Common/Worst case design trade-offs can be applied.

9. Voltage Control
Voltage High Threshold - Increase Power (Phantom Firing)
Voltage Low Threshold – Decrease Power (Clock Gate/Throttle)

10. Power distribution summary
Power delivery requirements are increasing
Architectural events, clock gating, power reduction techniques are a big source of the problem
Architects can help reduce it with intelligent voltage control
Control theory helps establish tight thresholds that guarantee reliability