Set-Associative Cache Way Group Control for Power-Performance Balance
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Solution Overview
Problem
Existing set-associative caches face challenges in balancing cache size with power efficiency, particularly when dealing with large data demands and high-speed processes, leading to inefficient power consumption and potential delays.
Innovation Solution
An operating method for a set-associative cache that selectively supplies power to SRAMs with different threshold voltages based on the system's operation state, allowing for dynamic adjustment of power distribution among way groups with varying leakage and speed characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a larger size cache is used to handle large data demands and high speed processes, then data access capability is improved, but power efficiency deteriorates
Solution Approach 1:
The cache is divided into multiple way groups, where each way group contains a plurality of ways. The controller can selectively activate or deactivate specific way groups based on the current operation state, such as hit rate and access patterns. This segmentation allows the cache to operate at different scales, activating only the necessary portion of the large cache when needed, thereby maintaining high data access capability while reducing power consumption during low-demand periods.
Solution Approach 2:
The cache system implements dynamic operation by adjusting the number of active ways based on real-time operation states. The controller monitors cache performance metrics and dynamically activates or deactivates way groups to match the current workload requirements. This dynamic adaptation enables the cache to optimize between performance and power efficiency continuously, rather than operating at a fixed state.
2Reliability
If all ways in a cache set are activated to improve hit rate, then cache performance is improved, but power consumption increases
Solution Approach 1:
Instead of activating all ways in a cache set simultaneously, the controller activates only the necessary number of ways based on the current operation state. When the hit rate is sufficient with fewer ways, the controller deactivates excess ways to reduce power consumption. This partial action approach maintains acceptable cache performance while minimizing energy loss by avoiding the activation of unnecessary cache ways.
Solution Approach 2:
The system changes the operational parameters of the cache by adjusting the number of active ways based on monitored performance metrics. When the operation state indicates lower demand or sufficient performance with fewer ways, the controller reduces the number of active ways, thereby changing the power consumption parameter while maintaining acceptable hit rates. This parameter adjustment resolves the contradiction between reliability and energy loss.
Data Source
AI summary
An operating method of a set-associative cache includes selecting one way group from among a first way group and a second way group with different threshold voltages based on an operation state of the set-associative cache, increasing a number of ways to which power is supplied in the selected one way group, analyzing a change in an operation state of a system including the set-associative cache as the number of ways to which the power is supplied is increased, and determining whether to further increase the number of ways to which the power is supplied based on an analyzed change in the operation state of the system.