Incremental Physical Design Optimization via Hybrid Netlist

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Solution Overview

Problem

Existing electronic design automation (EDA) tools require significant time to re-compile large systems when making localized changes, leading to undesirable re-processing of unmodified design portions and potential timing issues due to the heuristic nature of CAD algorithms.

Innovation Solution

A difference-based incremental physical design flow generates a hybrid netlist that leverages optimized nodes from previous compilations, allowing for minimal disruption by performing incremental placement and routing only on new or modified components, using placement and routing solutions from previous designs for unchanged components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If EDA tools re-compile the entire system when making localized changes, then completeness of design verification is improved, but compilation time increases significantly

Engineering Contradiction:

Improvedesign verification completenessVSAvoidcompilation time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent segments the design into modified and unmodified portions by generating a hybrid netlist that separates changed nodes from unchanged nodes. This allows the EDA tool to process only the modified segments while preserving the optimized unmodified segments, thereby reducing compilation time while maintaining verification completeness for the changed portions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies partial action by performing placement and routing optimizations only on the modified portions of the design rather than the entire system. The hybrid netlist enables the tool to skip re-processing of unmodified nodes, reducing the scope of action to exactly what is necessary while still ensuring design integrity.

Inventive Principle:

Principle #16Partial or excessive action

2Stability of the object's composition

If EDA tools process the entire system from scratch, then design consistency is improved, but processing time increases and previously achieved timing results may be degraded

Engineering Contradiction:

Improvedesign consistencyVSAvoidprocessing time

Core Design Contradiction:

Stability of the object's compositionVSLoss of time

Solution Approach 1:

The patent performs preliminary action by identifying and preserving the placement and routing solutions from the previous compilation for unmodified nodes before processing the modified portions. The hybrid netlist generation step captures the optimized state of unchanged nodes, allowing them to be reused without re-processing, thus maintaining design consistency while avoiding time loss.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent applies local quality by treating modified and unmodified portions of the design differently. Unmodified nodes retain their optimized placement and routing characteristics from the previous compilation, while modified nodes undergo re-optimization. This localized approach maintains overall design consistency while preserving the quality of unmodified sections.

Inventive Principle:

Principle #3Local quality

3Productivity

If incremental placement and routing is performed only on new/modified components, then compilation efficiency is improved, but risk of timing issues increases due to heuristic nature of CAD algorithms

Engineering Contradiction:

Improvecompilation efficiencyVSAvoidtiming result accuracy

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent implements feedback by using the placement and routing solutions from the previous compilation as a starting point for the incremental optimization. The hybrid netlist preserves the heuristic results from before, and the incremental placement and routing processes refine only the modified portions while considering the existing optimized structure, thereby maintaining timing accuracy while improving efficiency.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS11093672B2Method and apparatus for performing fast incremental physical design optimization

Publication Date: 2021.08.17 ALTERA CORP

AI summary

A method for implementing physical optimizations includes performing physical optimizations on a first reference version of a design, maintaining a computer-readable list of the physical optimizations, and during a subsequent compile for a second version of the design: identifying matching cells, nets, or both between the first reference version of the design and the second version of the design; and restoring at least a subset of the physical optimizations in the second version of the design by reading the computer-readable list of the physical optimizations and applying the subset to a computer-readable description of the second version of the design.