Processor Power Gating via Compiler-Driven Functional Unit Control
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Solution Overview
Problem
Current processor technologies face inefficiencies in reducing leakage power consumption, as many functional units remain idle and continue to consume power, with existing techniques failing to effectively manage power usage when units are not in use.
Innovation Solution
A hardware/software co-designed approach that identifies idle functional units and powers them down through a compiler-driven power gating mechanism, utilizing a scheduling technique and special power modes to optimize code and reduce power consumption, while minimizing overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If functional units are kept powered on to maintain readiness, then processor responsiveness and execution speed are improved, but power consumption increases due to leakage current in idle units
Solution Approach 1:
The processor is segmented into multiple independent functional units, each capable of being independently powered on or off. The power gating mechanism divides the power supply control into individual units based on their usage status, allowing selective power distribution to minimize leakage while maintaining readiness of required units.
Solution Approach 2:
The power state of functional units is made dynamic rather than static. The system transitions functional units between active and powered-off states based on real-time usage requirements, enabling the processor to adapt its power consumption profile to actual workload demands while maintaining responsiveness for required operations.
2Use of energy by moving object
If functional units are powered down to reduce leakage power, then power consumption is reduced, but processor performance and execution capability deteriorate when units are needed
Solution Approach 1:
The system performs preliminary analysis of instruction streams to predict which functional units will be needed and prepares them in advance by keeping them powered on or rapidly powering them up before actual execution is required. This preliminary planning ensures that power-down decisions do not compromise execution capability when units are actually needed.
Solution Approach 2:
The power gating mechanism incorporates feedback from the instruction stream analysis and unit usage patterns to dynamically adjust power states. The system continuously monitors which units are idle and which are required, using this feedback to make informed power management decisions that balance power savings with execution capability maintenance.
3Use of energy by moving object
If power gating is implemented to reduce leakage power, then power efficiency is improved, but system complexity increases due to power management overhead
Solution Approach 1:
The power gating mechanism is integrated into the existing processor control infrastructure, allowing the same control logic to serve both instruction scheduling and power management functions. This multi-functionality approach reduces overall system complexity by consolidating control responsibilities rather than adding separate dedicated power management subsystems.
Solution Approach 2:
The functional units themselves participate in the power management process by providing usage status information and responding to power state transitions. The system leverages existing unit status signals and control interfaces to implement power gating without requiring extensive external management infrastructure, allowing the processor to largely self-regulate its power consumption.
Data Source
AI summary
In one embodiment, the present invention includes an apparatus having a core including functional units each to execute instructions of a target instruction set architecture (ISA) and a power controller to control a power mode of a first functional unit responsive to a power identification field of a power instruction of a power region of a code block to be executed on the core. Other embodiments are described and claimed.