Processor Variable Wake-Up Latency Power Management
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional processors face challenges in reducing wake-up latency and power consumption when switching between sleep and normal modes due to simultaneous power management across all stages, leading to unnecessary static current consumption and prolonged recovery times.
Innovation Solution
A processor architecture with power switches controlled on a stage-by-stage or block-by-block basis, utilizing a power controller to measure and store wake-up latencies for each logic block, allowing for sequential power management and optimized switching times based on idiosyncratic wake-up latencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If power is cut off collectively to all stages when switching to sleep mode, then power consumption is reduced, but wake-up latency increases and productivity deteriorates
Solution Approach 1:
The processor divides the instruction processing pipeline into multiple independent stages (fetch, decode, issue, execute, write-back), each with its own power control switch. This segmentation allows selective power gating of individual stages rather than collective power cutoff, enabling stages that have finished their operations to be powered down while keeping active stages powered on, thus reducing overall power consumption without increasing wake-up latency.
Solution Approach 2:
The system performs preliminary detection of operation completion status for each stage before executing power cutoff. Power control switches are activated only after detecting that a stage has finished its operations, ensuring that no stage is powered down prematurely. This preliminary action prevents unnecessary wake-up delays while achieving power savings.
2Productivity
If power is supplied to all stages simultaneously when returning from sleep mode, then productivity is restored quickly, but power consumption increases due to unnecessary power supply to circuits that do not execute instructions
Solution Approach 1:
The power restoration process is segmented into stage-specific operations. Each stage has its own power control switch that can be independently activated. This allows the system to power on only the stages that need to execute upcoming instructions, rather than simultaneously powering all stages, thus reducing unnecessary power consumption while maintaining productivity.
Solution Approach 2:
The system uses feedback signals from each stage to determine when power should be supplied. Power control switches are controlled based on feedback regarding the operational status and instruction execution requirements of each stage. This feedback mechanism ensures that power is supplied precisely when and where needed, avoiding wasteful power consumption.
3Loss of energy
If power gating is applied to cut off leakage current, then energy efficiency improves, but wake-up operation complexity increases and device complexity worsens
Solution Approach 1:
The power gating mechanism is segmented into multiple independent power control switches, each associated with a specific pipeline stage. This segmentation distributes the control complexity across multiple simple, identical units rather than requiring one complex centralized controller, making the overall system easier to manage and implement.
Solution Approach 2:
Each power control switch is automatically controlled based on the operational status of its associated stage. The system self-manages power gating without requiring complex external control logic, as the completion detection and power switch activation are inherently linked to the stage's operational state, simplifying the overall power management architecture.
Data Source
AI summary
For a processor having a plurality of sequential stages, variable (or idiosyncratic) wake-up latencies and a method for managing power in such a processor are provided. Each sequential stage includes one or more logic blocks and one or more power switches. A power controller can measure wake-up latencies for the logic blocks and control the power switches of the logic blocks by referring to the measured wake-up latencies, respectively.