Arbitration Verification via Predictive Port Sampling
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Solution Overview
Problem
The asynchronous nature of requests in computing devices and uncertainty in network delays make it difficult to verify arbitration logic, particularly in selecting a frame for further processing among multiple ports, as existing methods struggle to accurately predict and validate arbitration winners.
Innovation Solution
A method and system that sample port availability information at least one clock cycle in advance of an arbitration point, predict potential winners, and compare these predictions to actual winners selected by the design under test, updating a reference model upon matching predictions, thereby verifying the arbitration logic effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If simulation is used to verify arbitration designs, then verification coverage can be achieved, but the asynchronous nature of requests and network delays make it difficult to accurately predict and verify arbitration winners
Solution Approach 1:
The system performs preliminary sampling of port availability information at least one clock cycle in advance of the arbitration point. This allows the verification system to predict arbitration winners before the actual arbitration occurs, enabling accurate verification despite asynchronous requests and network delays. The early sampling captures the state of ports before arbitration decisions are made, providing a reliable basis for prediction and verification.
2Measurement precision
If port availability information is sampled at least one clock cycle in advance, then accurate prediction of arbitration winners is enabled, but additional sampling operations and prediction logic increase verification system complexity
Solution Approach 1:
The verification system samples port availability information in advance of the arbitration point, capturing the state of ports before arbitration decisions are made. This preliminary sampling enables accurate prediction of arbitration winners by establishing a known state to compare against actual arbitration outcomes, improving measurement precision without requiring complex real-time analysis.
Solution Approach 2:
The system creates a reference model that copies the arbitration logic behavior based on sampled port availability information. This reference model serves as a simplified representation that can be used to predict arbitration winners and compare against actual outcomes, reducing the complexity of direct verification while maintaining prediction accuracy.
3Reliability
If multiple predicted arbitration winners are compared to actual winners, then verification reliability is improved, but the comparison process and reference model updates increase system complexity
Solution Approach 1:
The verification system implements feedback by comparing predicted arbitration winners with actual winners and using the results to update the reference model. When predictions match actual outcomes, the reference model is updated to reflect the verified behavior, improving future prediction accuracy. This feedback mechanism enhances verification reliability while maintaining manageable system complexity through iterative refinement.
Data Source
AI summary
A method for providing port arbitration verification for a design under test (DUT) is provided. The method includes sampling the availability of ports at a predetermined number of clock cycles prior to an arbitration point. The method predicts a winner at each of the clock cycles and determines a verification result based on a match between one of the predicted winners and an actual arbitration winner for the DUT.