Partial Cache Deactivation for Power and Performance Balance
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Solution Overview
Problem
Modern computer systems face challenges in effectively managing cache and memory hierarchies to balance performance and power consumption, as existing methods do not adequately address the trade-offs between cache efficiency and power usage.
Innovation Solution
A method for partial cache deactivation is implemented, where the system estimates leakage power based on voltage and temperature, identifies regions for deactivation based on cache hit counts, and adjusts the size of these regions based on leakage power and memory hierarchy bandwidth, while maintaining dynamic power within a threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the entire cache is kept active to maintain performance, then cache hit rate and access speed are improved, but leakage power consumption increases
Solution Approach 1:
The patent divides the cache into multiple regions (e.g., L1 cache and L2 cache, or different sections within a cache) and applies different power management policies to each region. By segmenting the cache, the system can deactivate specific regions that have low hit rates while keeping active regions with high hit rates, thus reducing overall leakage power without significantly impacting performance.
Solution Approach 2:
The patent applies different operational states to different cache regions based on their local characteristics (hit rates, access patterns). Regions with low utilization are deactivated to save power, while regions with high utilization remain active to maintain performance. This local differentiation allows the system to optimize the trade-off between power savings and performance maintenance.
2Loss of energy
If cache regions are deactivated to reduce leakage power, then power consumption decreases, but dynamic power and performance may increase
Solution Approach 1:
The patent implements dynamic power management by continuously monitoring cache performance metrics (hit rates, miss rates) and adjusting the operational state of cache regions in real-time. The system dynamically transitions between active and inactive states based on current workload patterns, ensuring that power savings are achieved without causing excessive dynamic power increases or performance degradation.
Solution Approach 2:
The patent employs feedback mechanisms where cache performance data is collected and used to adjust power management decisions. By monitoring hit rates and access patterns, the system can determine when to activate or deactivate cache regions, creating a closed-loop control system that balances power consumption and performance based on actual runtime behavior.
3Use of energy by moving object
If cache regions are selectively deactivated based on hit counts, then power efficiency improves, but system complexity increases
Solution Approach 1:
The patent implements self-service power management where the cache system automatically monitors its own performance metrics and makes power management decisions without external intervention. The cache controller autonomously identifies underutilized regions and deactivates them based on predefined policies, reducing the need for complex external control systems while maintaining power efficiency.
Solution Approach 2:
The patent changes operational parameters (power state, access permissions) of cache regions based on their performance characteristics. By adjusting parameters such as activation thresholds, deactivation criteria, and region sizes, the system achieves power efficiency with manageable complexity through parameter optimization rather than complex control logic.
Data Source
AI summary
A computing system performs partial cache deactivation. The computing system estimates the leakage power of a cache based on operating conditions of the cache including voltage and temperature. The computing system further identifies a region of the cache as a candidate for deactivation based on cache hit counts. The computing system then adjusts the size of the region for the deactivation based on the leakage power and a bandwidth of a memory hierarchy device. The memory hierarchy device is at the next level to the cache in a memory hierarchy of the computing system.