In-band Margin Probing for PCIe Interconnects

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Solution Overview

Problem

As computing systems evolve with increased processing power and complexity, existing interconnect architectures face challenges in efficiently managing communication between multiple processors and devices, particularly in maintaining optimal performance and power efficiency, especially in high-performance computing environments like servers and mobile devices.

Innovation Solution

The implementation of an interconnect apparatus and method that allows for in-band margin testing, where a root circuit sends margin test directives to downstream circuits during normal operating states, enabling them to perform tests and report results, thereby adjusting timing and voltage settings to minimize errors and ensure optimal operation without requiring separate test modes or equipment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional separate test modes and equipment are used for margin testing, then testing accuracy is improved, but device complexity and operational downtime increase

Engineering Contradiction:

Improvemargin testing accuracyVSAvoidtest equipment requirements

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the margin testing function with the operational data transmission function by embedding test directives and results within existing data packets transmitted over the interconnect. This eliminates the need for separate test equipment and modes, allowing testing to occur during normal operation without adding external complexity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The interconnect infrastructure is made multi-functional by enabling it to simultaneously perform both data transmission and margin testing. The same physical medium and protocol structure are used for both operational traffic and diagnostic testing, making the system more versatile while reducing the need for dedicated test resources.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Productivity

If in-band margin probing is implemented during normal operation, then productivity is improved, but measurement precision may worsen due to operational interference

Engineering Contradiction:

Improvetesting during operationVSAvoidmargin test accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent uses standardized data packets as intermediaries to carry margin test directives and results. These packets are processed through the normal interconnect protocol stack, which provides structured handling and timing control. This intermediary mechanism allows operational traffic and test traffic to coexist while maintaining measurement integrity through protocol-defined boundaries and error handling.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Measurement precision

If separate test modes are used for margin testing, then measurement precision is improved, but loss of time increases due to operational interruption

Engineering Contradiction:

Improvededicated test mode accuracyVSAvoidoperational downtime

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent enables continuous margin testing by integrating it into the operational data stream. Instead of pausing normal operations to perform tests, the system continuously transmits test directives embedded in data packets and collects results without interruption. This maintains the continuity of useful action (both data transmission and diagnostics) simultaneously.

Inventive Principle:

Principle #20Continuity of useful action

4Reliability

If traditional margin testing methods are used, then reliability is improved through comprehensive testing, but device complexity increases

Engineering Contradiction:

Improveinterconnect stabilityVSAvoidtesting infrastructure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements self-service margin testing where the interconnect devices perform their own diagnostics using embedded test directives in the data stream. Each device can autonomously initiate and process margin tests without external test equipment, reducing infrastructure complexity while maintaining reliability through self-diagnosis capabilities.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS11157350B2In-band margin probing on an operational interconnect

Publication Date: 2021.10.26 INTEL CORP

AI summary

There is disclosed in an example an interconnect apparatus having: a root circuit; and a downstream circuit comprising at least one receiver; wherein the root circuit is operable to provide a margin test directive to the downstream circuit during a normal operating state; and the downstream circuit is operable to perform a margin test and provide a result report of the margin test to the root circuit. This may be performed in-band, for example in the L0 state. There is also disclosed a system comprising such an interconnect, and a method of performing margin testing.