Event-Based Power Manager for Embedded Systems

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Solution Overview

Problem

Conventional power management techniques in embedded processing systems are inefficient due to reliance on predetermined workload information and fixed sampling intervals, leading to suboptimal frequency selection and potential performance degradation, especially in systems without task managers or accurate workload predictions.

Innovation Solution

An event-based power manager that dynamically adjusts power management based on inferred workload models, synchronizing with task periods and handling asynchronous events, allowing for adaptive and efficient power configuration without requiring explicit workload definitions or task manager interaction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If time-sliced control with fixed periodic sampling is used, then power management can be implemented independently from task management, but the sampling interval must be manually tuned and may not correlate with actual workload timing, leading to suboptimal frequency selection

Engineering Contradiction:
Improveindependence from task managementVSAvoidworkload measurement accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The power manager autonomously infers workload characteristics by monitoring processor events directly, eliminating the need for manual sampling interval configuration or task manager intervention. The system self-adjusts its observation strategy based on detected event patterns, achieving both independence and accuracy simultaneously.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system continuously monitors processor events and uses this feedback to dynamically adjust frequency selections. By establishing a closed-loop control where workload measurements directly inform power management decisions, the system achieves accurate adaptation without manual tuning.

Inventive Principle:
Principle #23Feedback

2Loss of energy

If the sampling interval is made longer to reduce overhead, then power management becomes less reactive to workload variations, but shorter intervals cause inconsistent workload measurements and degrade performance

Engineering Contradiction:
Improvepower management overheadVSAvoidresponsiveness to workload
Core Design Contradiction:
Loss of energyVSSpeed

Solution Approach 1:

The system transitions from static periodic sampling to dynamic event-driven monitoring. The observation rate adapts automatically based on workload characteristics, allowing the system to be highly responsive during active periods while minimizing overhead during idle periods through intelligent sampling strategies.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system performs preliminary analysis of event patterns to identify workload characteristics before making frequency selection decisions. By pre-processing event data and establishing workload models in advance, the system can make accurate frequency decisions without requiring continuous high-rate sampling.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If workload information is explicitly declared by the programmer, then DVFS algorithms can optimize frequency selection, but this increases programming effort and system overhead

Engineering Contradiction:
Improvefrequency optimization efficiencyVSAvoidprogramming effort
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The power manager autonomously infers workload characteristics by monitoring processor events directly, eliminating the need for manual sampling interval configuration or task manager intervention. The system self-adjusts its observation strategy based on detected event patterns, achieving both independence and accuracy simultaneously.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system uses processor events as an intermediary to indirectly measure workload characteristics without requiring explicit programmer input. By observing event timing and patterns, the power manager derives workload information automatically, serving as a mediator between hardware execution and power management decisions.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Use of energy by moving object

If the lowest frequency is selected to maximize energy efficiency, then static power consumption increases due to leakage current, but higher frequencies increase dynamic power consumption

Engineering Contradiction:
Improveenergy efficiencyVSAvoidperformance specification
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The system dynamically adjusts operating parameters (frequency and voltage) based on inferred workload characteristics. By changing these parameters adaptively rather than using fixed low-frequency operation, the system optimizes the balance between static and dynamic power consumption while meeting performance requirements.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system transitions from static low-frequency operation to dynamic frequency scaling. The operating frequency is continuously adjusted based on real-time workload assessment, allowing the system to operate at higher frequencies when needed (reducing static power proportion) and lower frequencies when idle (reducing dynamic power), thereby optimizing total energy consumption.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS10732698B2Event-based power manager
Publication Date: 2020.08.04 NXP BV
  • US10732698B2 patent drawing
  • US10732698B2 patent drawing
  • US10732698B2 patent drawing

AI summary

A technique for managing power in an embedded processing system includes generating a workload model for the embedded processing system in response to a control signal, an event status signal, and a reference clock signal. The control signal is received from a peripheral device. The event status signal is received from an event processor configured to control execution of tasks by a processor core of the embedded processing system. The technique includes providing power configuration information to the processor core. The power configuration information corresponds to an operating point selected based on the control signal, the event status signal, the reference clock signal, the workload model, and a predetermined energy model.