In-system Interconnect Validation via Error Injection
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Solution Overview
Problem
As data rates in serial interconnects like PCIe increase, validating link performance and RAS capabilities becomes challenging due to high bit error rates and lack of architected mechanisms, especially with the deployment of PAM-4 encoding, which affects functional correctness and expected link level performance across systems with components from multiple vendors.
Innovation Solution
The implementation of error injection and latency measurement mechanisms to validate interconnect components, including links and retimers, in an architected, automated, and standardized manner across all implementations using the same Link protocol, allowing for characterization of links and identification of root causes of malfunctions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If data rates in serial interconnects increase, then link performance and throughput are improved, but bit error rates increase and validation becomes more challenging
Solution Approach 1:
The patent applies preliminary action by injecting errors into the interconnect signal path before they can affect normal operation. The error injection mechanism proactively introduces controlled bit errors at known locations and times, allowing the system to validate error detection and correction capabilities before actual failures occur. This enables verification of RAS (Reliability, Availability, and Serviceability) capabilities at high data rates where BER would normally be too low to detect reliably.
Solution Approach 2:
The patent uses an intermediary approach by introducing a dedicated error injection mechanism that acts as a mediator between the high-speed interconnect and the validation system. This intermediary component can inject controlled errors into the signal path without disrupting normal high-speed operation, allowing validation of error handling capabilities while maintaining the high data rates needed for modern computing performance.
2Reliability
If error detection mechanisms are added to validate link performance, then reliability validation is improved, but device complexity increases
Solution Approach 1:
The patent applies universality by designing the error injection mechanism to serve multiple functions: it can inject errors for validating error detection capabilities, measure latency by timing error injection and detection events, and characterize link performance across different operating conditions. This multi-functional approach consolidates what would otherwise require separate validation mechanisms into a single integrated system, reducing overall complexity while improving validation capability.
Solution Approach 2:
The patent implements self-service by enabling the interconnect system to validate its own performance characteristics through built-in error injection and measurement capabilities. Rather than requiring external testing equipment or separate validation systems, the mechanism uses the interconnect's own operational signals and timing information to characterize link performance, reducing the need for additional complex external validation infrastructure.
3Ease of operation
If standardized validation mechanisms are implemented, then ease of operation and automation are improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies parameter changes by configuring the error injection mechanism with different error patterns, locations, and frequencies that can be programmed to validate specific link characteristics. The system can change parameters such as error injection timing, error types, and measurement intervals to adapt validation to different link configurations and performance requirements, enabling standardized automated validation across multiple platforms without requiring hardware changes.
Data Source
AI summary
Systems and devices can include an error injection register comprising error injection parameter information. The systems and devices can also include error injection logic circuit to read error injection parameter information from the error injection register, and inject an error into a flow control unit (Flit); and protocol stack circuitry to transmit the Flit comprising the error on a multilane link. The injected error can be detected by a receiver and used to test and characterize various aspects of a link, such as bit error rate, error correcting code, cyclic redundancy check, replay capabilities, error logging, and other characteristics of the link.