Memory Controller Segmentation for Address Translation Cache Efficiency
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Solution Overview
Problem
Current memory systems face inefficiencies in cache operations for logical-physical address translation information, leading to suboptimal performance due to limited cache hit rates and increased processing times for address translations.
Innovation Solution
The memory system divides logical-physical address translation information into multiple pieces, attaches metadata for each piece, and caches selected information in a second memory, improving cache hit rates by storing and retrieving relevant address translation tables efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If logical-physical address translation information is cached in a high-speed memory, then address translation speed is improved, but cache hit rate remains limited due to insufficient cache management
Solution Approach 1:
The patent segments the logical-physical address translation information into multiple separate address translation tables (first AT table, second AT table, etc.), each storing a portion of the translation information. This segmentation allows the system to manage and cache tables selectively, improving cache hit rates by ensuring frequently accessed tables are available in high-speed memory while maintaining comprehensive address translation coverage across all tables.
2Reliability
If all address translation tables are stored in high-speed cache memory, then cache hit rate is improved, but memory cost and complexity increase
Solution Approach 1:
The patent applies local quality by assigning different storage locations to different address translation tables based on their access characteristics. Frequently accessed AT tables are cached in high-speed memory (SRAM/DRAM), while less frequently accessed tables are stored in lower-speed, higher-capacity memory (NAND flash). This differentiated storage strategy optimizes cache hit rates for critical tables while avoiding the cost and complexity of caching all tables in high-speed memory.
Solution Approach 2:
The system performs preliminary actions by pre-loading frequently accessed address translation tables into high-speed cache memory before they are needed for address translation. The memory controller monitors access patterns and proactively caches AT tables that are likely to be needed, ensuring high cache hit rates without requiring all tables to be permanently resident in fast memory.
3Productivity
If address translation information is divided into multiple pieces and cached selectively, then cache management efficiency is improved, but processing overhead for table selection increases
Solution Approach 1:
The patent implements preliminary action by pre-computing and storing metadata (such as valid bit information, access frequency indicators, or priority markers) associated with each address translation table. This metadata is cached alongside the AT tables, allowing the memory controller to quickly identify and select the appropriate table for a given logical address without performing complex analysis at access time, thus minimizing processing overhead.
Solution Approach 2:
The system introduces an intermediary mechanism in the form of a cache management unit that maintains metadata about each address translation table's status and accessibility. This intermediary layer handles the complexity of table selection and validation, shielding the main address translation logic from having to process complex selection criteria, thereby improving overall processing efficiency.
Data Source
AI summary
A memory system includes a memory controller and a memory that is nonvolatile. The memory controller divides first information, which correlates a logical address with a physical address of the memory, into multiple pieces of second information, attaches metadata to each of the multiple pieces of second information and stores each piece of second information with the attached metadata, into the memory, when using third information, which is one of the multiple pieces of second information, reads, as multiple pieces of fourth information, pieces of second information including the third information, from among the multiple pieces of second information stored in the memory, selects fifth information, which is different from the third information, from among the read multiple pieces of fourth information based on the metadata attached to each of the multiple pieces of fourth information, and caches the selected fifth information into another memory.