XTS Cache Data Flushing During Power Loss
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Solution Overview
Problem
During a power loss event, existing technologies face challenges in efficiently flushing unaligned data from cache to memory, as this process requires padding, encryption, and alignment, which consume precious time and power.
Innovation Solution
The solution involves grouping unaligned data together, padding it if necessary to reach the size of a flash management unit (FMU), encrypting it, and then writing it to the memory device. This approach reduces the amount of padding and encryption required, thereby conserving power and time during a power loss event.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If unaligned data is padded and encrypted individually for each flash management unit, then data alignment requirements are met, but the time and power consumption increase significantly during power loss events
Solution Approach 1:
The patent combines multiple unaligned data segments into a single contiguous data structure before encryption. Instead of processing each unaligned data segment separately with individual padding and encryption operations, the method merges them together to form one unified data block that can be processed more efficiently, reducing the total number of encryption operations required during power loss events.
Solution Approach 2:
The patent performs data alignment and merging operations before the power loss event occurs. By preparing and consolidating unaligned data segments in advance while power is available, the system reduces the amount of critical processing needed during the time-constrained power loss flushing operation, thereby reducing the time and power required for the urgent flush operation.
2Ease of manufacture
If unaligned data is padded with dummy data to reach FMU size, then encryption can proceed, but the amount of data to be encrypted increases, consuming more power
Solution Approach 1:
The patent merges multiple small unaligned data segments into one larger contiguous data block. This consolidation reduces the total amount of padding required across all segments compared to padding each segment individually to reach FMU size. By combining data before padding, the system minimizes the volume of dummy data that needs to be generated and encrypted, thereby reducing power consumption.
3Ease of operation
If multiple FMUs are padded and encrypted separately, then each data segment can be processed independently, but the total operation time exceeds the available power duration
Solution Approach 1:
The patent performs data consolidation and alignment operations in advance while the system has full power availability. By preparing the data structure beforehand, the system transforms multiple independent processing tasks into a single consolidated operation that can be completed within the limited power duration available during a power loss event.
Solution Approach 2:
The patent combines multiple independent data processing operations into one unified encryption operation. By merging unaligned data segments into a single contiguous block before the power loss event, the system reduces the number of separate padding and encryption operations required, thereby completing the flush operation within the available power duration.
Data Source
AI summary
The present disclosure generally relates to a XTS cache operation during a power down event. Upon detection of power loss, data that is waiting to be encrypted needs to be flushed to the memory device. For any unaligned data or data less than a flash management unit (FMU) size, the data is grouped together and, if necessary, padded to reach the FMU size and then encrypted, merged with other data FMUs, and written to the memory device. Grouping the unaligned data reduces the amount of padding necessary to reach FMU size and also reduces the amount of data to be encrypted. As such, data flushing can be accomplished using the limited amount of remaining power during the power loss event.