Multicore Processor Leakage-Aware Power Management

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Solution Overview

Problem

Multicore processors face challenges in managing power consumption due to dynamic and static power dissipation, with existing power management modes either increasing leakage power over time or requiring state loss when powering off, leading to inefficiencies in power control.

Innovation Solution

A system dynamically manages power control by determining the power control break-even time based on leakage power behavior and performance levels, switching between two power management modes: one that halts switching variation and another that powers off the processor, using a variation monitor and evaluation logic to calculate and apply the most power-efficient mode based on expected idle time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the processor enters a power management mode that halts switching variation to reduce dynamic power consumption, then dynamic power consumption is reduced, but leakage power increases over time

Engineering Contradiction:
Improvedynamic power consumptionVSAvoidleakage power
Core Design Contradiction:
Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The system dynamically transitions between two power management modes based on real-time conditions. The first mode halts switching variation to reduce dynamic power, while the second mode powers off the processor to eliminate leakage power. The controller selects the optimal mode by comparing expected idle time against a calculated break-even time, making the power management strategy adaptive rather than static.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the operational parameters of the processor by switching between distinct power management modes. The break-even time calculation incorporates parameters such as leakage power rate, dynamic power consumption, and performance levels to determine the optimal switching point. This parameter-based decision-making allows the system to optimize power consumption under varying workload conditions.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If the processor powers off to eliminate leakage power, then leakage power is eliminated, but state information is lost requiring restore actions

Engineering Contradiction:
Improveleakage powerVSAvoidrestore time
Core Design Contradiction:
Loss of energyVSLoss of time

Solution Approach 1:

The system performs preliminary actions by saving processor state information before powering off. The controller determines whether to power off by comparing expected idle time against break-even time, ensuring that the processor only enters the powered-off state when the idle period is sufficiently long to justify the restore overhead. This preliminary assessment prevents unnecessary state loss and restore operations.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If existing power management modes are used without considering leakage variation, then implementation is simple, but power optimization is insufficient

Engineering Contradiction:
Improvepower management implementationVSAvoidoverall power loss
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

The system implements feedback mechanisms by monitoring processor activity and using variation indicators to detect changes in leakage power behavior. The controller continuously assesses whether the processor is active or idle and adjusts power management mode selections based on this feedback. The break-even time calculation is updated based on observed leakage variation, allowing the system to adapt to changing power characteristics over time.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The power management system transitions from static to dynamic operation by continuously monitoring processor state and leakage variation. The controller dynamically selects between power management modes based on real-time conditions rather than using fixed policies. This dynamic approach enables the system to respond to varying workload patterns and leakage characteristics, improving overall power optimization.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2664977B1Leakage variation aware power management for multicore processors
Publication Date: 2017.12.20 AVAGO TECHNOLOGIES GENERAL IP (SINGAPORE) PTE LTD
  • EP2664977B1 patent drawingFigure 1
  • EP2664977B1 patent drawingFigure 2
  • EP2664977B1 patent drawingFigure 3

AI summary

A system and method are provided to improve power efficiency of processor cores, such as processor cores in a multicore processor. A break-even time of a processor core may be determined that affects which power saving mode a processor core should enter when an expected idle of the processor core is identified. The break-even time of the processor core may be determined during run-time to help determine an applicable power saving mode that improves power efficiency of the processor core.