CPU Power Management via Peripheral Idle Prediction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power management methods for electronic systems, particularly those using ACPI, do not effectively balance power consumption and efficiency by dynamically adjusting idle periods and data transmission timing, leading to inefficient switching between low-power states and increased power consumption.
Innovation Solution
A power-management method that dynamically adjusts the idle counter period based on peripheral module activity, predicting idle periods to set the central processing unit to a second low-power state only when no data-access requests are made during extended idle periods, thereby extending the duration of low-power states and optimizing power usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the central processing unit enters the second low-power state (C3/C4) to reduce power consumption, then power saving is improved, but the response time to handle peripheral module data-access requests increases
Solution Approach 1:
The system performs preliminary actions by having peripheral modules send data-access requests before the CPU enters the second low-power state, or by buffering data in memory during idle periods. This ensures that when the CPU wakes from low-power state, the data is already prepared and can be processed immediately, reducing the effective response time while maintaining power savings during idle intervals.
Solution Approach 2:
The system dynamically adjusts the idle counter period and CPU power state based on actual system activity. The idle counter is extended when no peripheral activity is detected, allowing the CPU to enter deeper low-power states. When peripheral modules become active, the system transitions the CPU to appropriate power states, creating a dynamic balance between power consumption and response time based on real-time conditions.
2Use of energy by moving object
If the idle counter period is extended to allow longer low-power states, then power saving is improved, but the system's ability to respond to unexpected data-access requests deteriorates
Solution Approach 1:
The system uses feedback from peripheral module activity to control the idle counter and CPU power state transitions. When peripheral modules generate data-access requests, this feedback signal prevents the idle counter from extending further or wakes the CPU from low-power states. This feedback mechanism ensures the system maintains reliability by responding to actual activity while maximizing power savings during genuine idle periods.
Solution Approach 2:
The idle counter mechanism serves itself by automatically adjusting based on peripheral activity without requiring constant CPU intervention. The counter extends during idle periods and naturally resets when peripheral activity occurs, allowing the system to self-regulate between power-saving mode and active mode, improving both power efficiency and responsiveness.
3Reliability
If the system frequently switches between low-power states and working state, then responsiveness is improved, but power consumption increases due to unnecessary state transitions
Solution Approach 1:
The system performs preliminary actions by extending the idle counter period before transitioning the CPU to low-power states, ensuring that brief, sporadic peripheral activities don't cause premature wake-ups. This preliminary extension filters out noise and ensures only sustained idle periods result in state transitions, reducing unnecessary wake-ups and associated power consumption while maintaining system responsiveness.
Data Source
AI summary
A power-management method is provided, and the power-management method includes setting a central processing unit in a first low-power state when receiving a second low-power state request requiring the central processing unit to enter the second low-power state, obtaining first idle periods of the peripheral modules respectively to determine a second idle period according to the first idle periods of the peripheral modules, determining whether the peripheral modules have not sent a data-access request during the second idle period, setting the central processing unit in the second low-power state when the peripheral modules have not sent the data-access request during the second idle period, wherein each first idle period is an interval period between two data transmissions of each peripheral module.