Reconstructing Verification Test Graphs from Truncated Logs
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Solution Overview
Problem
Current post-silicon verification debugging methods face challenges in reconstructing a graph representation of a verification test due to limitations in circular buffer resources, which often result in truncated log data, missing start and end messages, and making it difficult to determine the actual order of actions during execution.
Innovation Solution
A method and system that utilize a processor to obtain and analyze truncated chronicle messages of start and end times of actions, reconstructing the graph representation based on a validated scenario, and automatically implanting print commands to determine the order of actions, allowing for the reconstruction of the graph representation of a previously executed verification test.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If all execution events are recorded during verification test execution, then complete debugging information is obtained, but circular buffer resources are quickly exhausted resulting in truncated log data
Solution Approach 1:
The patent extracts only the essential debugging information (start and end messages of actions) from the complete execution events, storing only these critical markers in the circular buffer. This extraction approach maintains the ability to reconstruct execution flow while significantly reducing the data volume required, thus preventing buffer exhaustion while preserving debugging capability.
Solution Approach 2:
Instead of recording all execution events completely, the patent implements partial recording by capturing only the necessary start and end markers of actions. This partial action approach provides sufficient information for debugging and execution path reconstruction without the excessive data storage requirements of complete event logging.
2Quantity of substance
If truncated log data is used due to buffer limitations, then circular buffer resources are preserved, but the ability to determine actual order of actions is degraded
Solution Approach 1:
The patent performs preliminary action by recording the start and end messages with their timestamps during execution. These pre-recorded markers serve as anchors that enable accurate reconstruction of the execution order even when intermediate events are truncated. The timestamps provide the necessary temporal information to determine the actual sequence of actions without requiring complete log data.
Solution Approach 2:
The start and end messages act as intermediary elements that mediate between the truncated log data and the execution order determination. These markers serve as reference points that allow the system to reconstruct the actual execution sequence despite missing intermediate events, effectively bridging the gap between incomplete data and accurate order determination.
3Measurement precision
If complete execution events are logged, then accurate execution path reconstruction is possible, but debugging tool complexity increases
Solution Approach 1:
The debugging tool extracts only the essential start and end messages from execution events, storing merely these critical markers. This extraction simplifies the data structure and reduces the complexity of processing, parsing, and analyzing execution logs, while still providing sufficient information for accurate execution path reconstruction.
Solution Approach 2:
Instead of storing complete execution events and then filtering them for analysis, the patent inverts the approach by recording only the necessary start and end markers from the beginning. This inversion simplifies the debugging tool's workload by eliminating the need to process and filter large volumes of complete event data, reducing overall system complexity.
4Ease of operation
If start and end messages are automatically implanted in test code, then execution order determination is simplified, but test code modification is required
Solution Approach 1:
The system performs preliminary action by automatically implanting start and end messages in the test code before execution. This preliminary instrumentation of the code simplifies the debugging process by ensuring that the necessary markers are already in place, making execution order determination straightforward without requiring manual code analysis or post-processing of complete event logs.
Data Source
AI summary
A method for reconstructing a graph representation of a previously executed verification test, may include obtaining a truncated chronicle of start time and end time messages of actions of the verification test that were logged during execution of the verification test on a design under test (DUT); using a processor, parsing and analyzing the start time and the end time messages to determine an order of the actions; using a processor, determining an order of other actions of said verification test, based on a graph representation of a verified scenario from which the verification test was generated; and reconstructing the graph representation of the verification test based on the determined order of the actions and order of the other actions.