PCI Express Bus Adaptive Variable Idle Timer
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Solution Overview
Problem
Existing information handling systems face challenges in balancing power conservation and performance due to fixed bus inactivity timer values that do not adapt to variable operating conditions, leading to suboptimal power management and reduced battery life in portable systems.
Innovation Solution
A system and method that dynamically adjust the bus inactivity timer value based on real-time analysis of bus activity, using a power manager and activity analyzer to balance power conservation and performance by optimizing the dwell time in low power states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a fixed inactivity timer value is used to transition the bus to low power state, then power consumption is reduced during idle periods, but system performance deteriorates due to delays in re-establishing link synchronization and inability to adapt to variable traffic patterns
Solution Approach 1:
The patent implements a dynamic inactivity timer mechanism where the timer value is adjusted based on monitored bus traffic patterns. The system transitions from a fixed timer approach to a dynamic one that adapts to varying operational conditions, allowing the bus to optimize between power savings and performance based on actual traffic requirements
Solution Approach 2:
The system employs feedback mechanisms by monitoring bus activity and using this information to adjust the inactivity timer value. The power manager continuously observes traffic patterns and modifies the timer setting accordingly, creating a closed-loop control system that balances power consumption and performance based on real-time conditions
2Loss of time
If the inactivity timer value is set to minimize performance impact, then system responsiveness is improved, but power consumption increases reducing battery life in portable systems
Solution Approach 1:
The patent changes the parameter of the inactivity timer value dynamically based on observed traffic patterns. Rather than using a single fixed value, the system adjusts this critical parameter to match actual operational needs, reducing response delays when traffic is frequent while maximizing power savings during extended idle periods
3Reliability
If link synchronization is maintained during idle periods by transmitting characters, then communication readiness is improved, but power consumption increases during idle states
Solution Approach 1:
The system applies partial action by transmitting only enough characters to maintain basic link synchronization during idle periods, rather than continuous full synchronization. This partial transmission approach maintains sufficient communication readiness while significantly reducing power consumption compared to maintaining full synchronization continuously
Data Source
AI summary
Power management of an information handling system PCI Express bus dynamically adjusts the inactivity time at the bus that is determined before initiation of a low power state by analyzing the transitions between low power and operating states over time. Dwell times of the bus in the low power state are compared with an inactivity goal to determine if the inactivity time should be adjusted up, such as when the bus enters the low power state too often, or should be adjusted down, such as when the bus enters the low power state too infrequently. In one embodiment, the dwell time is the time from entry into a low power state until initiation of the transition to an operating state and the inactivity goal is the time required for the bus to enter and exit the low power state.