Flash Memory Controller LBA Remapping Latency
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Solution Overview
Problem
Flash memory systems face inefficiencies in random read performance due to constrained cache sizes in mobile storage devices, leading to latency issues from invalid data in LBA layouts, which conventional methods address by re-mapping data but require transferring it between the host and storage system.
Innovation Solution
A memory controller within the flash storage system can execute LBA remapping commands independently, modifying logical-to-physical address maps without exchanging data with the host, thereby improving efficiency by aligning data and removing invalid entries within the LBA layout.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional LBA remapping methods are used to address invalid data, then data integrity is maintained, but data transfer between host and storage system is required which increases latency and reduces performance
Solution Approach 1:
The storage system performs LBA remapping autonomously without requiring host intervention or data transfer. The controller independently manages the L2P table updates and invalid data removal operations, allowing the system to service itself and eliminate the latency associated with host-storage data exchange while maintaining data integrity.
Solution Approach 2:
The system performs remapping operations in advance before data access is needed. By proactively updating the L2P table and removing invalid entries before they cause performance degradation, the system prevents latency issues from arising in the first place, thereby maintaining both data integrity and performance.
2Productivity
If LBA remapping is performed to align data and remove invalid entries, then random read performance is improved, but device complexity increases due to additional remapping operations
Solution Approach 1:
The patent combines multiple remapping operations into a single atomic LBA remap command. Instead of performing multiple separate data transfer and mapping operations, the system merges these into one coordinated operation that updates the L2P table and handles invalid data removal simultaneously, thereby improving random read performance without proportionally increasing device complexity.
Solution Approach 2:
The system creates a copy of the L2P table mapping information rather than physically moving data. By maintaining a logical copy of the address mapping relationships and updating this copy to reflect new LBA-to-physical address associations, the system achieves remapping functionality without the complexity of coordinated data transfer operations.
Data Source
AI summary
Devices and techniques are disclosed herein for remapping data of flash memory indexed by logical block addresses (LBAs) of a host device in response to re-map requests received at a flash memory system from the host device or in response to re-map requests generated at the flash memory system.