Storage Controller Cache Prioritization for Higher Read Hit Ratios
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Solution Overview
Problem
Existing storage devices face challenges in maximizing cache memory utilization due to inefficient management of data retention based on data characteristics, leading to decreased cache hit ratios and overall performance.
Innovation Solution
A storage controller that manages cache memory by setting priorities based on data characteristics, such as reusability, to selectively retain high-priority data and evict low-priority data, thereby optimizing cache memory usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If cache memory stores more data to increase cache hit ratio, then operating speed improves, but cache memory management complexity increases
Solution Approach 1:
The patent changes the parameter of data priority assignment by introducing a priority field in cache entries and implementing priority-based replacement policies. This allows the system to manage cache memory more efficiently by dynamically prioritizing data based on access patterns and data characteristics, resolving the contradiction between increasing cache hit ratio and managing cache complexity.
2Speed
If cache memory retains data longer to increase cache hit ratio, then operating speed improves, but cache memory utilization decreases
Solution Approach 1:
The patent implements dynamic cache management by introducing priority-based eviction policies and dynamic priority assignment. Cache entries are not statically retained but dynamically managed based on priority levels, allowing the system to extend retention for high-priority data while evicting low-priority data to maintain high utilization. This resolves the contradiction between retaining data longer and maintaining high cache utilization.
3Reliability
If priority-based data retention is implemented, then cache hit ratio increases, but device complexity increases
Solution Approach 1:
The patent segments cache management into priority-based categories by introducing priority fields and classification mechanisms. Data is segmented into different priority levels (e.g., high, medium, low) based on access patterns and characteristics, allowing selective retention and eviction. This segmentation approach increases cache hit ratio while managing complexity through structured priority classification rather than unmanaged complexity.
Data Source
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AI summary
A storage controller includes a host interface configured to communicate with a host, a buffer memory configured to buffer data read from a non-volatile memory, a cache memory including a plurality of cache lines and configured to store the data in at least one of the plurality of cache lines, and a cache controller configured to manage a status bitmap. The status bitmap indicates priority information of the plurality of cache lines according to an operation corresponding to a request received from the host interface, and the cache controller is further configured to select a victim cache line, among the plurality of cache lines, to be replaced based on the status bitmap. In this case, the operation corresponding to the request corresponds to one of normal read, prefetch, read-after-read, and read-after-prefetch.