Thread Scheduler Power Manager State Awareness
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Solution Overview
Problem
Traditional thread scheduling in computing systems does not consider detailed performance and idle state information of processors, leading to inefficient decisions regarding power and performance.
Innovation Solution
Implementing a thread scheduler that communicates with a power manager to utilize multi-level idle and performance state information of processors, applying weighted factors to select processors based on exit latencies and power savings, and prioritizing threads accordingly to optimize energy efficiency and responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the processor enters deep idle states to save power, then energy efficiency is improved, but exit latency increases causing slower response to scheduling requests
Solution Approach 1:
The power manager proactively monitors processor state and preemptively wakes up processors from idle states before the scheduler needs to assign tasks, ensuring processors are ready for immediate task execution without incurring latency penalties when scheduling occurs
Solution Approach 2:
The system continuously monitors processor idle states, exit latencies, and scheduling patterns, using this feedback to dynamically adjust power management decisions and scheduling policies to balance energy efficiency with responsiveness
2Ease of operation
If the scheduler selects processors without considering their current performance and idle states, then scheduling simplicity is maintained, but system performance and energy efficiency deteriorate
Solution Approach 1:
A power manager intermediary component is introduced between the scheduler and processors. This intermediary handles the complexity of monitoring processor states, calculating metrics, and making informed recommendations, allowing the scheduler to make simple selection decisions while the intermediary manages the complex state tracking and analysis
3Measurement precision
If the system tracks detailed multi-level performance and idle state information, then scheduling decision quality is improved, but system complexity increases
Solution Approach 1:
The system segments the complex state tracking into distinct components: the power manager handles processor state monitoring and metric calculation, while the scheduler handles task assignment. This segmentation allows detailed tracking without overwhelming the scheduling logic with complexity
Solution Approach 2:
The power manager acts as an intermediary that abstracts the complexity of multi-level state tracking. It collects detailed information about processor performance states and idle states, processes this information to calculate relevant metrics, and presents simplified recommendations to the scheduler, thereby managing complexity while maintaining measurement precision
Data Source
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AI summary
A computing system having a plurality of processing units configured to perform work by having threads assigned to the processing units. A thread scheduler is coupled to the plurality of processors and configured to schedule threads to the processing units. A power manager is coupled to the thread scheduler and controls performance states or idle states of the processing units. The thread scheduler maintains information about current performance state or idle state per processing unit. The information includes a multi-level description of the processing units in the computing system. The multi-level description includes three or more different entry values of different levels for performance state or idle state for processing units. The power manager provides the multi-level description of the processing units to the thread scheduler, which is configured to schedule threads to the processing units based on the multi-level description.