NUMA Node Migration with Spare Hardware for Cache Coherence
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Solution Overview
Problem
Existing technologies struggle to manage hardware failures in Non-Uniform Memory Access (NUMA) systems, particularly in scale-up systems, where maintaining cache coherence during node replacement is challenging.
Innovation Solution
The implementation of a spare node that can be activated to replace a failing node, with processor states and data migrated in-place while both nodes are running, using hardware-assisted migration features and cache coherence tracking schemes to maintain transparency to the operating system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a spare node is activated to replace a failing node in a NUMA system, then system reliability is improved, but device complexity increases due to the need for hardware-assisted migration features and cache coherence tracking schemes
Solution Approach 1:
The system maintains a spare node in standby mode with pre-configured hardware-assisted migration features and cache coherence tracking schemes. When a node failure is detected, the spare node is already prepared to receive and assume the identity of the failing node, enabling rapid replacement without system shutdown. This preliminary preparation resolves the contradiction by ensuring high reliability through pre-positioned redundancy while managing complexity through pre-configured rather than ad-hoc solutions.
Solution Approach 2:
The patent introduces an intermediary migration mechanism that facilitates seamless data and processor state transfer between nodes. This intermediary layer handles the complex coordination of cache coherence tracking and hardware-assisted migration, abstracting the complexity from the visible system architecture. The intermediary enables reliable node replacement while containing the complexity within the migration infrastructure rather than propagating it throughout the entire system.
2Loss of time
If processor states and data are migrated in-place while both nodes are running, then loss of time is reduced, but device complexity increases due to the need for cache coherence tracking schemes
Solution Approach 1:
The system enables continuous operation during node replacement by migrating processor states and data in-place while both the failing node and spare node remain running. The hardware-assisted migration features facilitate uninterrupted data transfer and processor state transfer, eliminating the need for system shutdown. This continuity approach reduces downtime significantly while managing complexity through dedicated hardware support for the migration process.
Solution Approach 2:
The patent implements a copying mechanism that creates a functional replica of the failing node's processor states and data in the spare node. This copying process occurs in-place during operation, allowing the spare node to assume the identity and functionality of the failing node without interrupting system operations. The copying approach enables time loss reduction by maintaining service continuity while containing complexity within the copying infrastructure.
3Manufacturing precision
If cache coherence is maintained during data migration, then manufacturing precision is improved in terms of data consistency, but device complexity increases due to cache coherence tracking schemes
Solution Approach 1:
The patent replaces complex software-based cache coherence tracking mechanisms with hardware-assisted migration features. This substitution uses dedicated hardware circuits and memory controllers to manage cache coherence during data migration, achieving precise data consistency without the overhead of complex software tracking schemes. The hardware-based approach maintains manufacturing precision in terms of data consistency while reducing the operational complexity of coherence tracking.
Solution Approach 2:
The system changes the state parameters of cache lines and memory controllers during migration to maintain coherence. By dynamically adjusting coherence state flags, migration status indicators, and memory controller configurations, the system achieves precise data consistency during the migration process. This parameter-based approach manages data consistency precision while containing complexity within controlled state transitions rather than requiring complex tracking algorithms.
Data Source
AI summary
One aspect of the application can provide a system and method for replacing a failing node with a spare node in a non-uniform memory access (NUMA) system. During operation, in response to determining that a node-migration condition is met, the system can initialize a node controller of the spare node such that accesses to a memory local to the spare node are to be processed by the node controller, quiesce the failing node and the spare node to allow state information of processors on the failing node to be migrated to processors on the spare node, and subsequent to unquiescing the failing node and the spare node, migrate data from the failing node to the spare node while maintaining cache coherence in the NUMA system and while the NUMA system remains in operation, thereby facilitating continuous execution of processes previously executed on the failing node.