Dynamic Garbage Collection Threshold Adjustment in Flash Storage
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Solution Overview
Problem
Current data storage devices using memory devices face inefficiencies in garbage collection (GC) operations, which can lead to performance degradation and reduced durability due to fixed threshold values that do not adapt to changing usage patterns.
Innovation Solution
A data storage device with a controller that monitors read operations, collects read operation information, and dynamically adjusts the GC threshold value based on the collected data, including read counts and soft decision performance, to optimize GC operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed GC threshold value is used, then the device structure is simple, but the GC operation efficiency deteriorates under changing usage patterns
Solution Approach 1:
The patent implements dynamic GC threshold adjustment by monitoring read operation frequencies and soft decision performance in real-time. The controller dynamically changes the GC threshold value based on actual usage patterns, transitioning from a fixed static value to a dynamic adaptive value that responds to changing workload conditions, thereby resolving the contradiction between structural simplicity and operational efficiency.
Solution Approach 2:
The patent changes the GC threshold parameter from a fixed constant to a variable that adapts based on read operation statistics and soft decision metrics. By modifying this key parameter dynamically according to monitored performance data, the system optimizes GC operation efficiency without requiring complete structural redesign, thus resolving the contradiction between simplicity and efficiency.
2Reliability
If GC operations are performed frequently, then data durability is improved, but device performance deteriorates due to excessive wear
Solution Approach 1:
The patent implements a feedback mechanism where the controller monitors read operation frequencies and soft decision performance, then uses this feedback to intelligently adjust GC threshold values. This feedback loop prevents unnecessarily frequent GC operations by only triggering GC when actually needed, thereby maintaining data durability while avoiding excessive wear and performance degradation.
Solution Approach 2:
The system performs self-optimization by automatically monitoring its own operational characteristics (read frequencies, soft decision needs) and autonomously adjusting GC thresholds without external intervention. This self-service capability ensures GC operations are performed only when necessary, balancing durability requirements with performance maintenance.
3Reliability
If the GC threshold value is lowered, then GC operation frequency is increased improving data recovery, but energy consumption increases
Solution Approach 1:
The patent dynamically adjusts the GC threshold parameter based on monitored read operation frequencies and soft decision performance. Instead of using a permanently low threshold that would increase energy consumption, the system adaptively sets the threshold only as low as necessary to ensure data recovery, thereby optimizing the balance between reliability and energy efficiency.
Data Source
AI summary
A data storage device includes a controller including a flash translation layer (FTL) for controlling an operation of a nonvolatile memory device. The FTL may monitor a first read operation on the plurality of data storage regions, collect first read operation information of a first subset of data storage regions on which the first read operation is performed, the first read operation information including read counts of the first subset of data storage regions on which the first read operation is performed, and information of the first subset of data storage regions on whether soft decision has been performed on the data storage regions, change a garbage collection (GC) threshold value based on the collected first read operation information, and control the nonvolatile memory device to perform GC on the plurality of data storage regions based on the changed GC threshold value.