Channel Tags for NAND Memory Translation Cache Optimization
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Solution Overview
Problem
Managed NAND memory lacks a global view of logical block accesses, leading to inefficiencies in internal optimization and increased cache misses due to limited context information being transmitted, such as relationships between logical blocks and future activities.
Innovation Solution
The system employs channel tags to provide context information, including channel IDs and expected future behavior, to the NAND memory, allowing it to pre-fetch entries into the translation cache, thereby optimizing logical to physical address translations and minimizing cache misses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the translation cache uses a fixed number of entries with basic logical block address mapping, then the cache structure is simple and fast to search, but the cache miss rate increases due to lack of context information for optimization
Solution Approach 1:
The patent applies preliminary action by pre-fetching translation entries into the cache before they are actually needed. The controller receives context information about future logical block accesses and proactively loads corresponding physical address translations into the cache, so that when future requests arrive, the translations are already available, reducing cache misses and improving translation speed
Solution Approach 2:
The patent implements feedback by using context information from the host system about future access patterns to guide cache pre-fetching decisions. The controller receives feedback regarding expected future logical block accesses and uses this information to optimize which entries to pre-load into the translation cache, creating a closed-loop system that adapts to access patterns
2Ease of operation
If the NAND memory receives only basic logical block access information, then the interface is simple, but the memory cannot perform internal optimizations due to lack of global view
Solution Approach 1:
The patent uses context information as an intermediary that carries semantic meaning about logical block accesses from the host system to the NAND memory controller. This intermediary structure allows the memory to understand the global view of access patterns without requiring a complex interface, as the context is transmitted through existing command structures in an extended format
3Measurement precision
If the translation cache is searched for every logical block address request, then accurate translations are obtained, but the search time increases when the cache does not contain the requested entry
Solution Approach 1:
The patent reduces search time by performing preliminary loading of translation entries into the cache based on predicted future access patterns. Instead of searching for every requested address, the system proactively populates the cache with entries that are likely to be needed soon, based on context information about future logical block accesses, thereby reducing both search frequency and search time
Data Source
AI summary
A method and system for performing logical to physical address translations in a memory is disclosed, wherein the memory includes a translation cache containing a subset of a plurality of entries mapping logical block addresses to physical locations of the memory. Aspects of the exemplary embodiment include receiving from a processor a read/write request for a logical block and context information regarding the logical block, the context information including at least one of a relationship of the logical block to other logical blocks and a description of future activity associated with the logical block; and pre-fetching a first entry into the translation cache based on the context information so that the first entry required to satisfy a future request is available in the translation cache when the future request is received.