Storage Controller Pre-fetching via Read Command Pattern Indexing
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Solution Overview
Problem
Storage devices face performance issues and increased power usage when handling random read requests, as traditional pre-fetch techniques often fail to predict non-sequential data access patterns, leading to inefficient data retrieval and increased power consumption.
Innovation Solution
A method and system that utilize a controller to generate a search sequence from current and prior read commands, calculate an index value, and retrieve historical data to pre-fetch data from a non-volatile memory, using techniques like hash functions and modulo operations to predict and pre-fetch data before actual read commands are received, optimizing data access in random read modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional pre-fetch techniques are used for random read requests, then the storage device attempts to pre-fetch data, but the prediction accuracy deteriorates leading to incorrect data pre-fetching
Solution Approach 1:
The system performs preliminary analysis of historical read command patterns before executing pre-fetch operations. By examining sequences of prior read commands and identifying access patterns, the system predicts future read locations with higher accuracy before actually pre-fetching data, ensuring that pre-fetching occurs only when prediction confidence is sufficient.
Solution Approach 2:
The system implements a feedback mechanism where actual read command outcomes are fed back into the pattern recognition algorithm. This allows the system to continuously refine its prediction models by comparing predicted vs. actual read patterns, improving prediction accuracy over time and reducing incorrect pre-fetch operations.
2Speed
If pre-fetch operations are performed for random read commands, then data retrieval may be accelerated, but power consumption increases due to unnecessary pre-fetching
Solution Approach 1:
Instead of performing full pre-fetch operations for all random read commands, the system applies pre-fetching selectively based on pattern recognition confidence levels. When access patterns indicate high probability of future reads at predicted locations, pre-fetch operations are executed partially or fully. When patterns are uncertain, the system reduces or eliminates pre-fetching, thereby reducing power consumption while maintaining speed benefits where applicable.
Solution Approach 2:
The system dynamically adjusts pre-fetch parameters such as pre-fetch size, timing, and activation threshold based on observed access patterns and prediction confidence. By changing these parameters adaptively, the system optimizes the balance between data access speed and power consumption, executing larger pre-fetch operations only when pattern confidence is high and reducing pre-fetch activity when patterns are unpredictable.
3Use of energy by moving object
If the storage device waits for the next read command to arrive before retrieving data, then power consumption is reduced, but latency increases
Solution Approach 1:
The system performs preliminary pattern recognition and prediction analysis during idle periods before actual read commands arrive. By pre-analyzing historical access patterns and predicting future read locations in advance, the system can initiate data retrieval operations earlier than traditional methods, reducing latency without requiring continuous power consumption for monitoring every incoming command.
Solution Approach 2:
The system uses its own historical read command data to generate predictions and trigger pre-fetch operations autonomously. Rather than requiring external control signals or continuous host communication, the pattern recognition mechanism serves itself by automatically analyzing its own access history and initiating appropriate data retrieval actions, thereby reducing latency without proportionally increasing power consumption.
Data Source
AI summary
Systems and methods for predicting read commands and pre-fetching data when a memory device is receiving random read commands to non-sequentially addressed data locations are disclosed. A limited length sequence of prior read commands is generated and that search sequence is then converted into an index value in a predetermined set of index values. A history pattern match table having entries indexed to that predetermined set of index values contains prior read commands that have previously followed the search sequence represented by the index value. The index value is obtained via application of a many-to-one algorithm to the search sequence. The index value obtained from the search sequence may be used to find, and pre-fetch data for, a next read command in the table that previously followed a search sequence having that index.