Dynamic Set Associative Cache Reducing Power Consumption
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The high power consumption of cache apparatus in processor systems, which accounts for 40%-50% of total processor power consumption, poses a significant challenge as existing methods to reduce it either require software support, result in performance loss, or introduce excessive hardware overheads.
Innovation Solution
A dynamic set associative cache apparatus is introduced, where a table unit records valid/invalid bits for cache blocks, allowing for dynamic enable/disable of cache ways based on block validity, reducing unnecessary access and power consumption during read/write operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the cache size is increased to improve processor performance, then the cache can store more data and reduce processor waiting time, but the power consumption of the cache increases significantly
Solution Approach 1:
The patent implements dynamic associativity by allowing the cache to change its associativity level (1-way, 2-way, 4-way, or 8-way) based on runtime conditions. The cache controller monitors cache hit rates and dynamically adjusts the number of active cache ways, enabling the cache to adapt its structure to balance performance and power consumption. When performance requirements are high, more cache ways are activated; when power saving is prioritized, fewer ways remain active.
Solution Approach 2:
The patent changes the operational parameters of the cache by dynamically adjusting the associativity level. The cache controller modifies the number of active cache ways (k value) based on monitored performance metrics, transforming the cache from a static structure to one with variable parameters. This allows the cache to optimize between full associativity for maximum performance and reduced associativity for lower power consumption.
2Use of energy by moving object
If existing methods are used to reduce cache power consumption, then energy usage decreases, but software support is required or performance is lost or hardware complexity increases
Solution Approach 1:
The cache system performs self-optimization through an integrated cache controller that autonomously monitors cache performance metrics (hit rates, access patterns) and dynamically adjusts the number of active cache ways without external intervention. The controller evaluates runtime conditions and automatically reconfigures the cache associativity, eliminating the need for software management while achieving both power savings and performance maintenance.
Solution Approach 2:
The patent introduces dynamic reconfigurability to the cache structure, allowing the associativity level to change at runtime based on actual workload characteristics. This dynamic approach replaces static cache designs with fixed parameters, enabling the system to adapt to varying performance and power requirements without requiring complex external control mechanisms.
Data Source
AI summary
The present invention provides a dynamic set associative cache apparatus for a processor. When read access occurs, the apparatus first determines a valid/invalid bit of each cache block in a cache set to be accessed, and sets, according to the valid/invalid bit of each cache block, an enable/disable bit of a cache way in which the cache block is located; then, reads valid cache blocks, compares a tag section in a memory address with a tag block in each cache block that is read, and if there is a hit, reads data from a data block in a hit cache block according to an offset section of the memory address.