Dynamic I/O Queue Scheduling for Storage Latency

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Solution Overview

Problem

Existing storage systems face challenges in efficiently managing system resources, particularly in ensuring fair utilization through workload-based, time-independent scheduling.

Innovation Solution

The implementation of workload-based, time-independent scheduling methods within storage systems to ensure fair resource utilization, which involves advanced algorithms and mechanisms for managing input/output operations and resource allocation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If traditional storage systems are used, then basic storage operations can be performed, but resource utilization is inefficient and fairness cannot be ensured

Engineering Contradiction:
Improveresource utilization efficiencyVSAvoidfairness of resource allocation
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements dynamic I/O scheduling that adapts to changing workload conditions in real-time. The scheduler continuously monitors system state and adjusts scheduling decisions dynamically, allowing the system to optimize resource utilization while maintaining fairness under varying load conditions. This dynamic approach resolves the contradiction by making resource allocation flexible rather than static.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes scheduling parameters based on workload characteristics and system state. By adjusting scheduling parameters dynamically, the system can optimize for both efficiency and fairness depending on current conditions. This parameter-based control allows the system to resolve the contradiction between productivity and reliability by adapting to different operational scenarios.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If advanced scheduling algorithms are implemented, then resource utilization efficiency improves, but system complexity increases

Engineering Contradiction:
Improveresource utilization efficiencyVSAvoidscheduling system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the scheduling system into distinct modules and layers, separating complex scheduling logic from simpler execution mechanisms. This segmentation allows advanced scheduling algorithms to be implemented in a structured way, managing complexity through modular design while maintaining high resource utilization efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces intermediary scheduling layers that mediate between high-level scheduling decisions and low-level execution. These intermediary components simplify the overall system complexity by providing clear interfaces and abstraction layers, allowing advanced algorithms to be implemented without proportionally increasing system complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If workload-based scheduling is implemented, then fairness of resource allocation improves, but latency may increase due to additional processing

Engineering Contradiction:
Improvefairness of resource allocationVSAvoidI/O operation latency
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent performs preliminary workload characterization and classification before actual I/O operations. By pre-analyzing workload patterns and categorizing them, the system can make faster scheduling decisions during execution, reducing the latency overhead associated with fairness-based scheduling while maintaining allocation fairness.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements optimized scheduling paths for certain workload types that can skip detailed fairness analysis when not necessary. This allows the system to maintain fairness where needed while rushing through operations where standard scheduling suffices, thereby reducing overall latency while preserving fairness guarantees.

Inventive Principle:
Principle #21Skipping (Rushing through)

Data Source

PatentUS12242896B2Queueing storage operations
Publication Date: 2025.03.04 PURE STORAGE INC
  • US12242896B2 patent drawing
  • US12242896B2 patent drawing
  • US12242896B2 patent drawing

AI summary

A method of scheduling input/output operations for a storage system including determining a deadline for a storage operation, wherein the deadline is dependent on an expected latency of the storage operation; adding the storage operation to a queue of storage operations; and reordering the queue dependent upon the deadline of the storage operation and one or more deadlines of one or more storage operations in the queue of storage operations.