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Energy and Code Size Efficiency - Coggle Diagram
Energy and Code Size Efficiency
Energy Efficiency
Power and Energy
Power Consumption
Rate of energy use, measured in watts
Determines power supply and cooling needs
Energy Consumption
Total power used over time
For constant power, E = Pt
Execution time
Faster processing may require more power
Finishing faster does not always save energy
CMOS Power
Dynamic power
Caused by transistor switching
Reduce switching activity to lower dynamic power consumption.
Supply voltage
Dynamic power depends on voltage squared
Lower voltage can substantially reduce power
Clock frequency
Higher frequency increases switching per second
Lower frequency reduces dynamic power
Code Size Efficiency
Instruction Compression
Compressed storage
Store instructions using fewer bits
Reduce memory area and instruction-fetch energy
Instruction decoding
Reconstruct instructions during fetching
Aim for little or no runtime penalty
Branch support
Decode instructions using limited context
Support branches to arbitrary addresses
Dictionary Compression
Instruction dictionary
Store each distinct instruction pattern once
Avoid repeating full instruction patterns
Lookup table
Store pointers to dictionary entries
Short pointers can reduce instruction storage
Memory Constraints
System on chip
Processor and memory share one chip
Memory can occupy a large portion of chip area