Speculative Read Command Execution in Data Storage Devices
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Solution Overview
Problem
Intermittent and varying data requirements from a host can lead to high access times for performance-critical data in data storage devices, resulting in lower system performance and reduced quality of service.
Innovation Solution
A data storage device with a controller that receives speculative read commands from a host, allowing partial execution of these commands during idle times or when surplus bandwidth is available, without impacting regular command execution. This involves reading data from non-volatile memory and storing it in buffers, which can be accessed by the host.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the host accesses data in long ranges with frequent variations, then the data storage device can handle diverse data requirements, but the access time for performance-critical data increases
Solution Approach 1:
The system performs preliminary actions by executing speculative read commands to pre-fetch data that may be needed in the future. The controller identifies patterns in host access behavior and proactively reads data from non-volatile memory into buffers before the host actually requests it, thereby reducing access time when the host does need the data.
Solution Approach 2:
The system dynamically adjusts its behavior based on host access patterns. The controller monitors the host's data requirements and adaptively determines which speculative read commands to execute, modifying the prefetching strategy in real-time to match changing access patterns while maintaining fast access for performance-critical data.
2Productivity
If speculative read commands are executed during idle time, then system performance is improved, but the complexity of command management increases
Solution Approach 1:
The system implements self-service by automatically managing speculative read commands without requiring complex external control. The controller autonomously monitors its own idle time, identifies suitable candidates for speculative reads based on observed patterns, executes them during idle periods, and manages the buffers independently, thereby improving performance while keeping the control mechanism relatively simple.
3Loss of time
If data is pre-read and stored in buffers, then access latency is reduced, but the bandwidth consumption during pre-fetching increases
Solution Approach 1:
The system applies partial action by executing speculative read commands only to the extent necessary - using surplus bandwidth during idle time rather than continuously. The controller reads data partially in advance based on predicted needs, storing it in buffers, and avoids excessive prefetching that would waste bandwidth, thereby reducing access latency while controlling bandwidth consumption.
Data Source
AI summary
A data storage device receives a speculative read command from a host identifying logical block addresses. The speculative read command is not required be to executed within a certain amount of time or even at all. The data storage device at least partially executes the speculative read command in response to determining that such execution will not reduce performance of the data storage device. At least partially executing the speculative read command causes data associated with at least some of the logical block addresses to be read from the non-volatile memory and stored in at least one buffer. Other embodiments are possible, and each of the embodiments can be used alone or together in combination.