Deferred Merge Graph Analysis for Timing Pessimism Reduction
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Solution Overview
Problem
Current techniques for timing analysis in electronic design automation (EDA) systems are overly pessimistic, leading to inaccurate worst-case behavior predictions, which can result in unnecessary resource consumption and redesigns in chip and circuit design.
Innovation Solution
A deferred merge method for graph-based analysis is introduced, where signals from multi-input cells are propagated separately until certain conditions are met, allowing for more accurate worst-case timing analysis by maintaining separate arrival times and delays, reducing pessimism in timing analysis results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If worst-case timing analysis selects the worst performing signals at each cell output, then timing analysis coverage is improved, but the results become overly pessimistic and inaccurate
Solution Approach 1:
The patent segments the timing analysis process into multiple stages, separating the propagation of different signal paths through the circuit. Instead of immediately merging all signals at each cell output, the system maintains separate signal representations until they actually converge at common outputs, allowing for more accurate worst-case timing analysis.
Solution Approach 2:
The patent introduces dynamic merging behavior where the merging of signals is conditional rather than static. Signals are merged only when they reach common outputs or when merging is required for subsequent analysis, allowing the system to adaptively manage signal propagation based on actual circuit topology and timing requirements.
2Device complexity
If immediate merging of signals is performed at each cell output, then computational complexity is reduced, but pessimism in timing analysis increases
Solution Approach 1:
The patent segments signal propagation into distinct paths and maintains separate signal representations throughout the circuit until convergence points are reached. This segmentation reduces the need for premature merging, thereby reducing pessimism while managing computational complexity through targeted signal tracking only where necessary.
Solution Approach 2:
The patent introduces an intermediary mechanism that tracks and manages signal paths without immediately merging them. This intermediary approach allows the system to maintain accurate timing information for multiple signals simultaneously, reducing pessimism while controlling computational resources through selective tracking.
3Reliability
If overly pessimistic timing results are generated, then safety margins are increased, but resource consumption and redesigns increase
Solution Approach 1:
The patent changes the parameters used in timing analysis by maintaining separate signal representations with their individual timing characteristics rather than using merged worst-case values. This parameter change allows for more accurate timing predictions that reflect actual signal propagation, reducing unnecessary safety margins while maintaining adequate reliability.
Solution Approach 2:
The patent replaces the mechanical approach of immediate signal merging with a more sophisticated signal propagation mechanism that tracks individual signal paths. This substitution allows the system to achieve both accuracy and efficiency by only performing necessary analysis where signal convergence actually occurs.
Data Source
AI summary
An approach is described for a method, system, and product for deferred merge based method for graph based analysis to reduce pessimism. According to some embodiments, the approach includes receiving design data, static and/or statistical timing analysis data, identifying cells and interconnects for performing graph based worst case timing analysis where merger of signals is deferred based on one or more conditions to reduce pessimism, and generating results thereof. Other additional objects, features, and advantages of the invention are described in the detailed description, figures, and claims.