Host-Side Data Caching with Hot-Cold L2P Mapping
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Solution Overview
Problem
Existing host devices using Host Performance Booster (HPB) technology face inefficiencies due to memory resource wastage and performance reduction from mixing cold and hot files, as well as frequent updating of mapping tables.
Innovation Solution
Implementing a method in the host device to categorize files as hot, warm, or cold based on access frequency and heat thresholds, reallocating logical addresses, and updating L2P tables accordingly to cache hot and warm files, while deleting mappings for cold files, thereby reducing table updating frequency and optimizing memory usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If HPB technology is implemented to cache mapping tables in host device memory, then data access performance is improved, but memory resources are wasted due to mixed storage of cold and hot files
Solution Approach 1:
The patent segments files into hot files and cold files based on access frequency, and separately manages their mapping tables. Hot file mappings are cached in host device memory while cold file mappings are not, thereby avoiding memory waste from caching all files uniformly.
Solution Approach 2:
The patent applies different caching strategies to different types of files based on their access characteristics. Hot files receive aggressive caching in host memory while cold files do not, optimizing memory utilization according to local file access patterns.
2Measurement precision
If mapping tables are frequently updated to reflect file access patterns, then cache accuracy is improved, but host device performance is reduced due to update overhead
Solution Approach 1:
The patent implements periodic heat checks to determine whether files have become hot or cold, rather than continuously monitoring and updating. This periodic approach maintains sufficient cache accuracy while reducing the performance overhead compared to continuous updates.
Solution Approach 2:
The patent changes the parameter of file heat classification (hot vs. cold) based on access frequency thresholds, allowing the system to adapt caching behavior to file access patterns without requiring continuous real-time updates, thus balancing accuracy and performance.
3Speed
If all files are cached in host device memory, then data access speed is improved, but memory capacity is exceeded and resource efficiency deteriorates
Solution Approach 1:
The patent segments the file population into hot and cold categories, caching only hot files in host device memory. This segmentation enables the system to cache a manageable subset of files that provides the most performance benefit, avoiding memory capacity exhaustion.
Solution Approach 2:
The patent extracts and caches only the essential hot file mappings in host device memory, leaving cold file mappings in storage device memory. This selective extraction optimizes memory capacity utilization while maintaining data access speed for frequently accessed files.
Data Source
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AI summary
A method for caching data, and a host device and a storage system that caches data. The method includes determining a first file in a storage device as a first predetermined type of file; reallocating a logical address of a predetermined logical address region to the first file; and updating a first logical address to physical address (L2P) table, corresponding to the predetermined logical address region, in a cache of the host device. The updated first L2P table includes a mapping relationship between the logical address reallocated for the first file and a physical address of the first file.