Storage Device Command Fetch Policy Adaptation
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Solution Overview
Problem
Storage devices face delays in processing commands, leading to unsatisfied command processing time requirements due to inefficiencies in fetching commands from multiple command queues.
Innovation Solution
A storage device with a command fetch circuit and controller that determines a policy to fetch commands from multiple command queues based on the state of a target queue, either following an order-based policy or a round-robin policy, to optimize command processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If commands are fetched from multiple command queues using a fixed order-based policy, then command processing follows a predictable sequence, but command processing delays occur when specific queues have excessive commands
Solution Approach 1:
The patent implements dynamic policy switching between first-in-first-out (FIFO) and round-robin fetching strategies based on real-time queue states. When a target queue exceeds a threshold number of commands, the system switches to round-robin policy to distribute fetching across multiple queues, preventing excessive delays while maintaining reliability of command processing time requirements.
2Loss of time
If commands are fetched using a round-robin policy from all queues, then command processing delays are reduced, but processing order consistency is lost
Solution Approach 1:
The system changes the fetching policy parameter dynamically based on queue state parameters. When the target queue has fewer than the threshold number of commands, FIFO policy maintains processing order consistency. When the target queue exceeds the threshold, round-robin policy is applied to reduce processing delays, thus adapting the parameter to current system conditions.
3Stability of the object's composition
If the storage device always processes commands from the target queue in order, then command processing order is maintained, but latency deviations across queues increase
Solution Approach 1:
The controller continuously monitors the number of commands in the target queue and uses this feedback to determine whether to apply FIFO or round-robin fetching. This feedback mechanism allows the system to detect when the target queue has excessive commands and switch to round-robin policy, reducing latency deviations while maintaining processing order when appropriate.
Data Source
AI summary
A storage device may fetch commands from a plurality of command queues. The storage device may determine a policy for fetching commands from the plurality of command queues as a first policy or a second policy on the basis of the state of a target command queue among the plurality of command queues. The policy may control an order in which commands are fetched from the plurality of command queues.