Circuit Re-simulation Using Essential Signal Classification
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Solution Overview
Problem
Current circuit simulation methods require saving extensive data, leading to increased processing time due to frequent hard disk accesses, and re-simulation from the beginning when errors are detected, which is inefficient for debugging and analyzing signal behavior.
Innovation Solution
Classifying circuit signals as essential and non-essential, saving data only for essential signals during the initial simulation, and re-simulating only the selected subcircuit during a specified subinterval based on the behavior of essential signals, allowing for more efficient data storage and reduced re-simulation time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complete simulation data for all signals is saved during circuit simulation, then debugging accuracy is improved, but processing time increases due to frequent hard disk accesses
Solution Approach 1:
The patent segments simulation data into two categories: checkpoint data (saved periodically for all signals) and waveform data (saved on-demand for specific signals). This segmentation allows the system to maintain debugging accuracy by preserving essential signal information while reducing overall data storage requirements, thereby decreasing hard disk access frequency and processing time.
Solution Approach 2:
The patent applies local quality by differentiating data retention strategies for different signal types. Critical signals maintain full waveform data for precise debugging, while non-critical signals use checkpoint data only. This selective approach optimizes the balance between debugging accuracy and processing efficiency by allocating storage resources based on signal importance.
2Measurement precision
If re-simulation is performed from the beginning of the full simulation interval when errors are detected, then complete error analysis is achieved, but turnaround time increases
Solution Approach 1:
The patent implements preliminary action by pre-saving checkpoint data at regular intervals throughout the simulation. When an error is detected, these pre-saved checkpoints enable the system to restart simulation from the appropriate checkpoint rather than from the beginning, significantly reducing turnaround time while maintaining complete error analysis capability.
Solution Approach 2:
The patent extracts and saves essential checkpoint data periodically during simulation, separating it from complete waveform data. This extraction allows error analysis to be performed using only the necessary subset of data, enabling faster re-simulation from checkpoints without requiring access to the entire simulation dataset.
3Loss of time
If checkpoint data is saved only periodically, then processing time is reduced, but ability to analyze errors between checkpoints is limited
Solution Approach 1:
The patent introduces waveform data as an intermediary between checkpoint data and complete simulation records. When errors are detected between checkpoints, the system can retrieve and analyze relevant waveform data for specific signals during the error interval, providing detailed signal behavior information without requiring complete data storage, thus balancing processing time with information completeness.
Data Source
AI summary
A netlist description of a circuit is processed to classify some signals of the circuit as essential signals and to classify all other signals of the circuit as non-essential signals. Thereafter when simulating behavior of the entire circuit in response to input signals supplied over some time interval, a simulator saves first simulation data representing behavior of the circuit's essential signals during the time interval. Thereafter the simulator is programmed to re-simulate behavior of only a selected subcircuit of the circuit during only a selected subinterval of the full time interval based on behavior of essential signals described by the first simulation data. During the re-simulation, the simulator saves second simulation data representing behavior of both essential and non-essential signals of the subcircuit to provide a more complete picture of the behavior of the selected subcircuit during the selected subinterval. Before the initial full-circuit simulation, each signal is classified as an essential signal when its behavior during the full-circuit simulation must be represented by the first simulation data in order to provide sufficient information to program the simulator to re-simulate the behavior any selected subcircuit during any selected subinterval. All other circuit signals are classified as non-essential signals whose behavior need not be represented by the saved first simulation data.