Technology Challenges Motivating Adaptive Techniques | p. 1 |
Introduction | p. 1 |
Motivation for Adaptive Techniques | p. 2 |
Components of Power | p. 2 |
Relation Between Frequency and Voltage | p. 2 |
Control Loop Implementation | p. 4 |
Practical Considerations | p. 4 |
Impact of Temperature and Supply Voltage Variations | p. 7 |
Technology Issues Relating to Performance-Enhancing Techniques | p. 9 |
Threshold Voltage Variation | p. 9 |
Random Dopant Fluctuations | p. 11 |
Design in the Presence of Threshold Voltage Variation | p. 13 |
Technology Issues Associated with Leakage Reduction Techniques | p. 14 |
Practical Considerations | p. 15 |
Sources of Leakage Current | p. 16 |
Transistor Design for Low Leakage | p. 20 |
Conclusion | p. 21 |
References | p. 21 |
Technological Boundaries of Voltage and Frequency Scaling for Power Performance Tuning | p. 25 |
Adaptive Power Performance Tuning of ICs | p. 25 |
AVS- and ABB-Scaling Operations | p. 28 |
Frequency Scaling and Tuning | p. 31 |
Power and Frequency Tuning | p. 33 |
Leakage Power Control | p. 37 |
Performance Compensation | p. 40 |
Conclusion | p. 44 |
References | p. 46 |
Adaptive Circuit Technique for Managing Power Consumption | p. 49 |
Introduction | p. 49 |
Adaptive VDD Control | p. 50 |
Dynamic Voltage Scaling | p. 50 |
Frequency and Voltage Hopping | p. 51 |
Adaptive VTH Control | p. 55 |
Reverse Body Bias (VTCMOS) | p. 55 |
Self-Adjusting Threshold Voltage (SAT) Scheme | p. 55 |
Leakage Current Monitor | p. 56 |
VTH Controllability | p. 57 |
Device Perspective | p. 59 |
Forward Body Bias | p. 60 |
Control Method and Granularity | p. 61 |
VTH Control Under Variations | p. 64 |
VTH Control vs. VDD Control | p. 66 |
Hardware and Software Cooperative Control | p. 68 |
Cooperation Between Hardware and Application Software | p. 68 |
Cooperation Between Hardware and Operating System | p. 70 |
Conclusion | p. 71 |
References | p. 71 |
Dynamic Adaptation Using Body Bias, Supply Voltage, and Frequency | p. 75 |
Introduction | p. 75 |
Static Compensation with Body Bias and Supply Voltage | p. 76 |
Adaptive Body Bias | p. 77 |
Adaptive Supply Voltage | p. 82 |
Dynamic Variation Compensation | p. 84 |
Dynamic Body Bias | p. 84 |
Dynamic Supply Voltage, Body Bias, and Frequency | p. 87 |
Design Details | p. 87 |
Measurement Results | p. 89 |
Conclusion | p. 92 |
References | p. 92 |
Adaptive Supply Voltage Delivery for Ultra-Dynamic Voltage Scaled Systems | p. 95 |
Logic Design for U-DVS Systems | p. 97 |
Device Sizing | p. 98 |
Timing Analysis | p. 100 |
SRAM Design for Ultra Scalable Supply Voltages | p. 101 |
Low-Voltage Bit-Cell Design | p. 104 |
Periphery Design | p. 105 |
Intelligent Power Delivery | p. 107 |
Deriving VDD for Given Speed Requirement | p. 107 |
DC-DC Converter Topologies for U-DVS | p. 109 |
Linear Regulators | p. 109 |
Inductor Based DC-DC Converter | p. 109 |
Switched Capacitor Based DC-DC Converter | p. 110 |
DC-DC Converter Design and Reference Voltage Selection for Highly Energy-Constrained Applications | p. 112 |
Minimum Energy Tracking Loop | p. 113 |
Conclusion | p. 119 |
References | p. 120 |
Dynamic Voltage Scaling with the XScale Embedded Microprocessor | p. 123 |
The XScale Microprocessor | p. 123 |
Chapter Overview | p. 124 |
XScale Micro-Architecture Overview | p. 125 |
Dynamic Voltage Scaling | p. 126 |
The Performance Measurement Unit | p. 127 |
Dynamic Voltage Scaling on the XScale Microprocessor | p. 129 |
Running DVS | p. 130 |
Impact of DVS on Memory Blocks | p. 134 |
Guaranteeing SRAM Stability with DVS | p. 134 |
PLL and Clock Generation Considerations | p. 138 |
Clock Generation for DVS on the 180 nm 80200 XScale Microprocessor | p. 138 |
Clock Generation 90 nm XScale Microprocessor | p. 139 |
Conclusion | p. 142 |
References | p. 142 |
Sensors for Critical Path Monitoring | p. 145 |
Variability and its Impact on Timing | p. 145 |
What Is a Critical Path | p. 147 |
Sources of Path Delay Variability | p. 148 |
Process Variation | p. 149 |
Environmental Variation | p. 149 |
Timing Sensitivity of Path Delay | p. 151 |
Critical Path Monitors | p. 158 |
Synchronizer | p. 158 |
Delay Path Configuration | p. 159 |
Time-to-Digital Conversion | p. 163 |
Sensitivity | p. 167 |
Control and Calibration | p. 168 |
Conclusion | p. 169 |
Acknowledgements | p. 171 |
References | p. 171 |
Architectural Techniques for Adaptive Computing | p. 175 |
Introduction | p. 175 |
Spatial Reach | p. 177 |
Temporal Rate of Change | p. 177 |
"Always Correct" Techniques | p. 179 |
Look-up Table-Based Approach | p. 179 |
Canary Circuits-Based Approach | p. 180 |
In situ Triple-Latch Monitor | p. 181 |
Micro-architectural Techniques | p. 182 |
Error Detection and Correction Approaches | p. 183 |
Techniques for Communication and Signal Processing | p. 184 |
Techniques for General-Purpose Computing | p. 186 |
Introduction to Razor | p. 187 |
Razor Error Detection and Recovery Scheme | p. 188 |
Micro-architectural Recovery | p. 190 |
Recovery Using Clock-Gating | p. 190 |
Recovery Using Counter-Flow Pipelining | p. 191 |
Short-Path Constraints | p. 192 |
Circuit-Level Implementation Issues | p. 192 |
Silicon Implementation and Evaluation of Razor | p. 195 |
Measurement Results | p. 196 |
Total Energy Savings with Razor | p. 197 |
Razor Voltage Control Response | p. 199 |
Ongoing Razor Research | p. 200 |
Conclusion | p. 202 |
References | p. 203 |
Variability-Aware Frequency Scaling in Multi-Clock Processors | p. 207 |
Introduction | p. 207 |
Addressing Process Variability | p. 209 |
Approach | p. 209 |
Combinational Logic Variability Modeling | p. 212 |
Array Structure Variability Modeling | p. 213 |
Application to the Frequency Island Processor | p. 215 |
Addressing Thermal Variability | p. 217 |
Experimental Setup | p. 218 |
Baseline Simulator | p. 218 |
Frequency Island Simulator | p. 219 |
Benchmarks Simulated | p. 219 |
Results | p. 220 |
Frequency Island Baseline | p. 220 |
Frequency Island with Critical Path Information | p. 221 |
Frequency Island with Thermally Aware Frequency Scaling | p. 222 |
Frequency Island with Critical Path Information and Thermally Aware Frequency Scaling | p. 224 |
Conclusion | p. 225 |
Acknowledgements | p. 225 |
References | p. 225 |
Temporal Adaptation - Asynchronicity in Processor Design | p. 229 |
Introduction | p. 229 |
Asynchronous Design Styles | p. 230 |
Asynchronous Adaptation to Workload | p. 232 |
Data Dependent Timing | p. 234 |
Architectural Variation in Asynchronous Systems | p. 237 |
Adapting the Latch Style | p. 237 |
Controlling the Pipeline Occupancy | p. 240 |
Reconfiguring the Microarchitecture | p. 241 |
Benefits of Asynchronous Design | p. 244 |
Conclusion | p. 245 |
References | p. 245 |
Dynamic and Adaptive Techniques in SRAM Design | p. 249 |
Introduction | p. 249 |
Read and Write Margins | p. 250 |
Voltage Optimization Techniques | p. 251 |
Column Voltage Optimization | p. 252 |
Row Voltage Optimization | p. 255 |
Timing Control | p. 257 |
Array Power Reduction | p. 259 |
Sleep Types | p. 259 |
Active Sleep | p. 260 |
Passive Sleep | p. 261 |
P Versus N Sleep | p. 263 |
Entering and Exiting Sleep | p. 264 |
Dynamic Cache Power Down | p. 266 |
Data Bus Encoding | p. 266 |
Reliability | p. 267 |
Soft Errors | p. 267 |
Hard Errors | p. 267 |
Cache Line Disable | p. 268 |
Cache Line Remap | p. 268 |
Defect Correction | p. 268 |
Conclusion | p. 269 |
References | p. 270 |
The Challenges of Testing Adaptive Designs | p. 273 |
The Adaptive Features of the Itanium 2 9000 Series | p. 273 |
Active De-skew | p. 273 |
Cache Safe Technology | p. 277 |
Foxton Technology | p. 278 |
The Path to Production | p. 281 |
Fundamentals of Testing with Automated Test Equipment (ATE) | p. 281 |
Manufacturing Test | p. 281 |
Class or Package Testing | p. 283 |
System Testing | p. 285 |
The Impact of Adaptive Techniques on Determinism and Repeatability | p. 286 |
Validation of Active De-skew | p. 287 |
Testing of Active De-skew | p. 290 |
Testing of Power Measurement | p. 291 |
Power Measurement Impacts on Other Testing | p. 294 |
Test Limitations and Guard-Banding | p. 296 |
Guard-Band Concerns of Adaptive Power Management | p. 297 |
Conclusion | p. 300 |
References | p. 300 |
Index | p. 303 |
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