Parallel Address Hint Validation for I/O Latency

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

In multi-node data storage systems, non-owner nodes face inefficiencies and performance penalties due to cache coherency issues and increased latency when handling read I/O operations, as they may retrieve invalid content or incur additional latency from remote procedure calls to owner nodes for address resolution.

Innovation Solution

The system partitions ownership of logical address spaces among nodes, allowing non-owner nodes to perform parallel address resolution and use address hints to validate content, while dynamically switching between optimized and normal read processing based on system resources and metrics like CPU utilization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If non-owner nodes perform remote procedure calls to owner nodes for address resolution, then address resolution can be performed, but read I/O latency increases due to additional communication overhead

Engineering Contradiction:

Improveaddress resolution accuracyVSAvoidread I/O latency

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The system performs address resolution in advance by having owner nodes pre-compute and store address hints (physical addresses) for logical addresses in their local caches. When a non-owner node needs to access data, it can use these pre-computed address hints directly without needing to perform remote procedure calls to owner nodes for address resolution, thereby eliminating the communication overhead and reducing latency.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention creates copies of address resolution information (address hints) and distributes them to non-owner nodes. Instead of requiring non-owner nodes to query owner nodes for address resolution, each non-owner node maintains local copies of address hints in its cache, allowing it to perform address resolution independently and simultaneously retrieve data, thus eliminating the sequential dependency and reducing overall latency.

Inventive Principle:

Principle #26Copying

2Loss of time

If non-owner nodes retrieve content using local address resolution, then read latency may be reduced, but content validity cannot be guaranteed due to cache coherency issues

Engineering Contradiction:

Improveread I/O latencyVSAvoidcontent validity

Core Design Contradiction:

Loss of timeVSReliability

Solution Approach 1:

The system implements a feedback mechanism where non-owner nodes send validation requests to owner nodes to verify the validity of cached address hints before using them for data retrieval. The owner node responds with validation information indicating whether the address hint is current and valid. This feedback loop ensures content validity while allowing the system to use optimized local address resolution paths, as the validation step only occurs when needed and does not block the overall read operation.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

Instead of requiring full validation of all address hints before every read operation, the system performs partial validation only when there is suspicion of invalidity or based on timeout conditions. The non-owner node attempts read operations using cached address hints first, and only performs validation requests to owner nodes when necessary, thus balancing the trade-off between validation thoroughness and read latency.

Inventive Principle:

Principle #16Partial or excessive action

3Productivity

If the system uses optimized read processing with parallel processing, then read performance improves, but system complexity increases due to additional validation logic

Engineering Contradiction:

Improveread performanceVSAvoidprocessing logic complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The read processing logic is segmented into distinct modular components: address hint retrieval from cache, parallel data retrieval using the hint, validation request generation, validation response processing, and result merging. Each component is independently implemented and can be optimized separately. This segmentation makes the complex validation logic more manageable and maintainable while preserving the performance benefits of parallel processing.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS20250021229A1Double-mapping technique of I/O latency optimization

Publication Date: 2025.01.16 DELL PROD LP

AI summary

In at least one embodiment, processing can include: receiving, at a first node, a read operation that reads content of a logical address, wherein a second node, but not the first node, owns the logical address; and performing optimized read processing for the read operation. The optimized read processing can include: performing, in parallel, first processing that obtains a first address hint and first content corresponding to the logical address, and second processing that obtains a second address hint corresponding to the logical address; determining whether the first and second address hints match; if the first and second address hints match, determining that first content is valid content stored at the target logical address; if the first and second address hints do not match, determining the first content is not stored at the logical address, and using the second address hint to obtain second content stored at the logical address.