L2P Mapping Compression for Larger Address Range Coverage
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Solution Overview
Problem
Memory systems face inefficiencies in handling large ranges of physical addresses due to the limitations of logical-to-physical (L2P) mappings stored in cache, leading to slow retrieval processes when expanding beyond the cached range.
Innovation Solution
Compressing L2P mappings by consolidating consecutive physical addresses into single entries with offset indicators, allowing the mapping to cover an expanded range without increasing cache size, and implementing dynamic compression strategies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If L2P mappings are expanded to cover larger ranges of physical addresses, then the memory system can handle more address space, but the cache size requirement increases
Solution Approach 1:
The L2P mapping table is divided into multiple segments or levels. Instead of storing all physical address mappings in a single flat cache, the mapping is segmented into hierarchical levels where higher levels map to lower levels, enabling coverage of larger address spaces with limited cache memory.
Solution Approach 2:
The patent introduces hierarchical levels as an additional dimension to the traditional flat L2P mapping structure. By adding this vertical dimension (levels), the system can map much larger address ranges without proportionally increasing the cache size, as each level stores only a portion of the total mapping information.
2Measurement precision
If L2P mappings are stored in full detail in cache, then address translation accuracy is maintained, but processing latency increases
Solution Approach 1:
The hierarchical L2P mapping structure performs preliminary address translation at upper levels before accessing lower levels. This staged approach allows the system to quickly eliminate large portions of the address space that don't match, reducing the time needed to find the exact physical address while maintaining full translation accuracy.
Solution Approach 2:
The address translation process is segmented into multiple hierarchical stages. Each level of the hierarchy handles a portion of the translation task, allowing the system to maintain precision through multi-stage verification while reducing overall latency by distributing the work across multiple faster, smaller cache levels.
3Productivity
If conventional L2P mapping structures are used, then implementation simplicity is maintained, but memory system performance is limited
Solution Approach 1:
The hierarchical L2P mapping structure is designed to be dynamically adaptable. The system can adjust which levels are actively used based on workload characteristics, and the mapping entries can be dynamically allocated across hierarchical levels to optimize performance for different access patterns while managing complexity through structured flexibility.
Data Source
AI summary
Methods, systems, and devices for techniques for logical-to-physical information compression are described. In some cases, a memory system may compress a logical-to-physical (L2P) mapping to expand the quantity of physical addresses mapped by the L2P mapping. For example, if a set of consecutive entries of an uncompressed L2P mapping includes consecutive physical addresses, the memory system may compress the consecutive entries into a single entry which includes a starting physical address of the consecutive physical addresses. Additionally, the memory system may include an indication of a starting logical address corresponding to the starting physical address in the compressed entry. To identify a physical address within the compressed entry, the memory system may determine an offset between a logical address corresponding to the physical address and the starting physical address using the indication, and may apply the offset to the starting physical address to determine the physical address.