Memory Replay Logic for Point-to-Point Interconnect Error Recovery

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Solution Overview

Problem

Conventional memory bus architectures struggle to maintain reliability, availability, and serviceability (RAS) as processor speeds increase, particularly in point-to-point memory interconnects like fully-buffered DIMM technology, which face challenges in error detection and correction due to higher data rates.

Innovation Solution

A memory controller with replay logic that analyzes transaction response data for errors, performs hardware-based resets, and replays transactions, supporting various memory transactions, including reads, writes, and configuration operations, to ensure data integrity and system reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If point-to-point memory interconnects are used to support higher data rates, then memory speed increases, but error detection and correction capabilities deteriorate

Engineering Contradiction:
Improvememory data rateVSAvoiderror detection and correction capability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent applies preliminary action by implementing replay logic that proactively detects transaction errors and automatically retries failed memory transactions before they propagate to the processor. The system performs preliminary error detection on read and write transactions, and when errors are detected, it automatically replays the transaction without requiring processor intervention, thus maintaining reliability at high data rates.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback mechanisms through replay logic that continuously monitors memory transactions for errors and uses this information to trigger automatic retries. The system establishes a feedback loop where transaction responses are analyzed, error conditions are detected, and corrective replay actions are automatically initiated, creating a self-correcting system that maintains reliability despite high-speed operation challenges.

Inventive Principle:
Principle #23Feedback

2Reliability

If conventional multi-point memory bus architecture is used, then error detection and correction mechanisms can be implemented, but memory speed and data rate increase is limited

Engineering Contradiction:
Improveerror detection and correction capabilityVSAvoidmemory data rate
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The patent introduces replay logic as an intermediary component between the memory interface and the processor. This intermediary layer intercepts memory transactions, performs error detection, and automatically retries failed transactions before forwarding data to the processor. This mediator approach enables the system to use high-speed point-to-point interconnects while maintaining error detection and correction capabilities that were traditionally only available in conventional multi-point architectures.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If firmware-based retry mechanisms are used for memory transactions, then error recovery is possible, but system complexity and processing overhead increase

Engineering Contradiction:
Improvetransaction error recovery capabilityVSAvoidfirmware and reset mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements self-service by enabling the memory controller to automatically detect and recover from transaction errors without requiring firmware intervention or system resets. The replay logic autonomously monitors transactions, detects errors, and retries failed operations, making the system self-healing for common memory errors. This eliminates the need for complex firmware-based retry mechanisms and full system resets, reducing both complexity and processing overhead while maintaining reliable error recovery.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP1984822B1Memory transaction replay mechanism
Publication Date: 2010.01.20 INTEL CORP
  • EP1984822B1 patent drawingFigure 1
  • EP1984822B1 patent drawingFigure 2
  • EP1984822B1 patent drawingFigure 3

AI summary

Embodiments of the invention are generally directed to systems, methods, and apparatuses for memory replay mechanisms. In some embodiments, the replay logic includes reset logic to reset at least some of the links in a point-to-point memory interconnect. In addition, the replay logic may include a replay queue to store transaction data and a replay controller to initiate a reset if the transaction data indicates a defined transaction response error. Other embodiments are described and claimed.