SSD Bandwidth Limiting via QoS Command Prioritization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for limiting bandwidth in SSDs are inefficient and wasteful, as they consume large amounts of resources and are considered invasive, failing to accurately provide guaranteed bandwidth and quality of service without slowing down data speeds.
Innovation Solution
A storage device executes commands at full speed while delaying the writing of completion entries to a completion queue and sending interrupt signals based on associated bandwidth quality-of-service levels, allowing for prioritization and efficient resource management without reducing data throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If bandwidth limiting methods slow down data flow rate or count bytes/commands, then bandwidth can be limited, but data speeds are reduced and large amounts of bandwidth are consumed
Solution Approach 1:
The patent applies preliminary action by pre-assigning QoS levels to commands before execution. The controller determines the QoS level for each command based on predefined policies, allowing it to proactively manage bandwidth allocation without needing to slow down data flow or count bytes during execution. This pre-planning enables efficient bandwidth limiting while maintaining optimal data speeds.
Solution Approach 2:
The patent changes the parameter of command prioritization by introducing QoS levels as a new dimension for command management. Instead of treating all commands equally or using simple byte-counting methods, the system assigns different QoS levels (e.g., high, medium, low) to commands based on their importance and bandwidth requirements. This parameter change enables differentiated bandwidth allocation without reducing overall data throughput.
2Quantity of substance
If bandwidth limiting methods count bytes or commands as they are processed, then bandwidth can be controlled, but the method is invasive and consumes large amounts of bandwidth
Solution Approach 1:
The patent extracts the bandwidth limiting function from the data processing path itself. Instead of counting bytes or commands as they flow through the system (which would require intrusive monitoring), the controller separates bandwidth management into a distinct QoS determination process. The controller determines QoS levels based on command characteristics and policies without needing to intercept or count actual data bytes, thereby reducing invasiveness and bandwidth consumption for monitoring purposes.
Solution Approach 2:
The system implements self-service by having the controller automatically determine QoS levels for commands based on predefined policies and command characteristics. The bandwidth limiting mechanism serves itself by using the existing command queue structure and controller logic to enforce QoS requirements, without requiring external monitoring systems or complex byte-counting infrastructure. This self-managing approach reduces overall system complexity.
3Productivity
If existing bandwidth limiting methods are used, then some bandwidth control is achieved, but they are wasteful and inefficient
Solution Approach 1:
The patent applies preliminary action by pre-determining QoS levels for commands before they are executed. The controller analyzes command characteristics and assigns appropriate QoS levels in advance, allowing efficient bandwidth allocation without needing to waste resources on post-execution analysis or byte-counting. This proactive approach maximizes productivity by ensuring that bandwidth is allocated optimally from the start, reducing waste of SSD resources.
Solution Approach 2:
The patent introduces QoS levels as a new parameter for command prioritization, replacing inefficient byte-counting methods. By changing the management parameter from raw byte counts to meaningful QoS levels, the system achieves more efficient bandwidth control that better reflects actual service requirements. This parameter change reduces waste by focusing bandwidth allocation on command importance rather than arbitrary byte thresholds.
Data Source
AI summary
The present disclosure generally relates to limiting bandwidth in storage devices. One or more bandwidth quality of services levels may be selected and associated with commands according to service level agreements, which may prioritize some commands over others. A storage device fetches and executes one or more the commands. Each of the commands is associated with a bandwidth quality of service level. After executing the commands and transferring the data to a host device, the storage device may delay writing a completion entry corresponding to the executed commands to a completion queue based on the associated bandwidth quality of service level of the commands. The device may then delay revealing the completion entry by delaying updating a completion queue head pointer. The device may further delay sending an interrupt signal to the host device based on the associated bandwidth quality of service level of the commands.