Dual Node Controller Architecture for Hot-Swap Multi-CPU Systems

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Solution Overview

Problem

In multi-CPU systems with Non-Uniform Memory Access Architecture, the limited number of CPU interconnect ports restricts scalability, and the process of replacing a node controller (NC) for reliability causes system delays and affects cross-domain access, especially when NC reliability decreases.

Innovation Solution

Implementing a dual NC group architecture where the main CPU manages the system to switch cross-domain access routes from one NC group to another, allowing for hot removal and addition of NCs without disrupting system performance by modifying route configurations and initiating system silence.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single NC is used for cross-domain access in a multi-CPU system, then the system structure is simple, but the system delay increases and reliability decreases when NC replacement is needed

Engineering Contradiction:
Improvesystem reliabilityVSAvoidsystem delay
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The single NC is segmented into multiple independent NC groups (first NC group and second NC group), each capable of handling cross-domain access independently. This segmentation allows the system to switch between groups without complete system interruption, reducing delay while maintaining reliability through redundancy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system changes the operational parameter from single-NC mode to multi-NC group mode dynamically. By modifying route configurations and initiating system silence protocols, the system can switch between different NC groups based on reliability requirements, thereby reducing system delay during NC replacement while maintaining high availability.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If an NC is removed for reliability reasons, then system reliability improves, but cross-domain access is affected and system performance deteriorates

Engineering Contradiction:
ImproveNC reliabilityVSAvoidcross-domain access performance
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system introduces an intermediary switching mechanism that redirects cross-domain access from the removed NC to an alternative NC group. This intermediary routing layer ensures that reliability is improved through NC replacement while productivity is maintained through seamless traffic redirection without performance deterioration.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The NC group configuration is made dynamic, allowing the system to adaptively switch between different NC groups based on operational needs and reliability requirements. This dynamic reconfiguration enables hot removal and addition of NCs without disrupting cross-domain access performance, maintaining both reliability and productivity.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If dual NC groups are implemented for hot-swap capability, then system scalability and reliability improve, but device complexity increases

Engineering Contradiction:
Improvehot-swap capabilityVSAvoidNC group configuration complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Both NC groups are designed with universal functionality to handle identical cross-domain access tasks. This multi-functionality allows either group to take over completely, simplifying the management complexity despite having dual groups. The standardized interface and routing logic reduce the operational complexity while maintaining hot-swap capability and scalability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3575977B1CPU and multi-CPU system management method
Publication Date: 2024.08.28 XFUSION DIGITAL TECH CO LTD
  • EP3575977B1 patent drawingFigure 1
  • EP3575977B1 patent drawingFigure 2
  • EP3575977B1 patent drawingFigure 3

AI summary

The present invention provides a multi-CPU system, where the multi-CPU system includes: at least two Quick-Path Interconnect QPI domains, a first node controller NC group, and a second node controller NC group; according to a CPU route configuration, there is at least one CPU that can access a CPU in another QPI domain by using the first NC group; and there is at least one CPU that can access a CPU in another QPI domain by using the second NC group. According to this topology, hot swap of an NC can be implemented while the system is relatively slightly affected.