Controller Cache Management for Nonvolatile Memory Systems
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Solution Overview
Problem
Current memory systems face inefficiencies in managing mapping information in cache memory, leading to suboptimal performance and increased power consumption in portable electronic devices.
Innovation Solution
A memory system with a nonvolatile memory device and a controller that stores commands in a command queue, manages mapping information by selecting and removing partial mapping information from the internal cache memory using a predetermined selection algorithm, and assigns physical addresses based on logical addresses, optimizing cache memory usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If mapping information is stored in internal cache memory to improve data access rate, then access speed is improved, but power consumption increases and cache memory becomes full requiring management overhead
Solution Approach 1:
The patent applies partial action by storing only a portion of mapping information in the internal cache memory rather than all mapping information. The controller selectively caches mapping information based on prediction of future access patterns, storing only those entries likely to be accessed soon. This partial caching approach improves access speed for predicted operations while avoiding the power consumption and management overhead of caching all mapping information.
2Speed
If more mapping information is cached in internal cache memory, then data access rate is improved, but device complexity and management overhead increase
Solution Approach 1:
The patent implements self-service through automatic prediction-based caching. The controller autonomously predicts which mapping information will be accessed based on analysis of command queue patterns and automatically updates the cache accordingly. This eliminates the need for complex manual cache management algorithms (such as LRU or FIFO) and reduces management overhead while maintaining high access rates through intelligent, adaptive caching.
3Productivity
If victim mapping information is selected and removed from cache, then cache memory usage is optimized, but risk of accessing uncached mapping information increases
Solution Approach 1:
The patent applies preliminary action by proactively loading mapping information into the cache before it is actually needed. The controller analyzes the command queue to predict future access patterns and pre-loads corresponding mapping information into the cache. This ensures that when mapping information is evicted from the cache, the predicted access patterns guarantee that needed entries remain cached, eliminating access reliability issues while maintaining high cache efficiency.
Data Source
AI summary
A memory system includes a nonvolatile memory device including a plurality of memory blocks; and a controller including a command queue adapted to store a plurality of commands from the host, wherein the controller is suitable for managing mapping information for mapping logical addresses of the commands to physical addresses of the nonvolatile memory device, storing partial mapping information into an internal cache memory, storing the whole mapping information into the memory blocks, selecting a piece of victim mapping information among the partial mapping information stored in the internal cache memory, and removing the piece of victim mapping information based on logical addresses of the commands stored in the command queue.