Stochastic DVFS Controller for Power-Performance Trade-offs
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Solution Overview
Problem
Existing dynamic voltage and frequency scaling (DVFS) methods struggle to balance power saving and performance guarantees, particularly in latency-sensitive applications and web servers, due to their reliance on heuristic techniques that are not workload-aware, leading to unsatisfactory real-time and quality of service (QoS) metrics.
Innovation Solution
A stochastic controller-based DVFS system that uses Karhunen-Loeve expansion (KLE) to decompose workload random processes into deterministic functions, optimizing voltage and frequency settings based on workload performance error data, thereby ensuring tight performance and reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If heuristic DVFS control algorithms are used, then power saving is achieved, but real-time performance and QoS metrics deteriorate
Solution Approach 1:
The patent implements a feedback mechanism where the controller continuously monitors workload performance error data and adjusts voltage and frequency settings dynamically. The controller receives feedback about actual workload execution and modifies DVFS parameters in real-time to maintain performance guarantees while optimizing power consumption, resolving the contradiction between power saving and reliability.
Solution Approach 2:
The system dynamically changes voltage and frequency parameters based on workload characteristics and performance requirements. By adjusting these parameters adaptively rather than using fixed heuristic rules, the system achieves both power savings and maintains real-time performance guarantees for latency-sensitive applications.
2Device complexity
If fixed DVFS control algorithms are used, then simplicity is maintained, but adaptability to random workload patterns deteriorates
Solution Approach 1:
The patent transitions from static, fixed DVFS control algorithms to dynamic control that adapts to changing workload patterns. The controller dynamically adjusts voltage and frequency settings based on real-time workload performance error data, enabling the system to adapt to random workload patterns while maintaining manageable complexity through systematic control methods.
Solution Approach 2:
The DVFS controller automatically adjusts system parameters based on workload characteristics without requiring external intervention or complex pre-programming. The system self-adapts to different workload patterns by monitoring performance error and autonomously optimizing voltage and frequency settings, achieving both adaptability and operational simplicity.
3Productivity
If processor frequency is increased to meet real-time requirements, then performance is improved, but power consumption increases
Solution Approach 1:
The patent applies partial action by increasing processor frequency only when and to the extent necessary to meet real-time performance requirements. Rather than maintaining high frequency continuously, the system adjusts frequency dynamically based on actual workload demands, achieving necessary performance while minimizing power consumption during lower-demand periods.
Solution Approach 2:
The system implements periodic adjustment of voltage and frequency settings based on workload monitoring intervals. The controller periodically evaluates performance error data and makes adjustments accordingly, enabling the processor to operate at high speed only during periods when real-time requirements demand it, rather than maintaining high power consumption continuously.
Data Source
AI summary
A method and apparatus controls power consumption of at least one processor core by generating dynamic voltage and clock frequency scaling control information based on stochastic controller control parameters and workload performance error data. A processor core's voltage and clock frequency is varied based on the generated dynamic voltage and clock frequency scaling control information. In one example, a stochastic controller, is coupled to a dynamic voltage and clock frequency scaling (DVFS) circuit. The stochastic controller uses the stochastic controller control parameters and workload performance error data and generates the dynamic voltage and clock frequency scaling control information to control the DVFS circuit. Related methods are also disclosed.