Multi-Fanout Net Routing Resource Limiting
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Solution Overview
Problem
Traditional routing techniques for multi-fanout nets in integrated circuits are inefficient, leading to increased runtime and suboptimal route quality due to the sequential routing of individual loads, which results in varying signal propagation delays and poor scalability as circuit complexity increases.
Innovation Solution
The method involves limiting the routing resources available for multi-fanout nets by defining a bounding perimeter and excluding routing resources that do not conform to a specified template or are located in regions without loads, thereby reducing the number of resources to be considered during routing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If routing resources are limited by excluding regions without loads, then routing runtime is reduced, but routing flexibility is constrained
Solution Approach 1:
The routing fabric is segmented into multiple regions, with each region containing at least one load. By identifying and excluding regions without loads, the router focuses computational efforts only on relevant segments, reducing runtime while preserving flexibility within the active regions.
Solution Approach 2:
Regions without loads are extracted and excluded from the routing consideration. This removes unnecessary computational overhead from areas that cannot contribute to the routing solution, thereby reducing runtime without impacting the ability to find optimal paths through regions that do contain loads.
2Productivity
If routing resources are limited by excluding non-conforming resources, then routing runtime is reduced, but routing solution quality may deteriorate
Solution Approach 1:
Routing resources are pre-evaluated and classified according to template conformance before the actual routing process. Resources that do not conform to the specified template are identified and excluded in advance, allowing the router to focus only on conforming resources and avoid wasted computational efforts, thereby reducing runtime while maintaining solution quality.
3Ease of manufacture
If multi-fanout nets are routed sequentially one load at a time, then routing implementation is simplified, but routing runtime increases
Solution Approach 1:
Multiple loads of the multi-fanout net are merged into a single routing expansion process. The router processes all loads simultaneously by identifying regions containing loads and exploring routing resources that can serve multiple loads, thereby reducing the overall runtime compared to sequential processing while maintaining implementation simplicity.
4Stability of the object's composition
If routing resources are limited to conforming resources, then routing symmetry is maintained, but routing resource utilization decreases
Solution Approach 1:
Different routing resources are evaluated based on their local properties and template conformance. By maintaining symmetry only where it applies (in conforming resources) while excluding non-conforming resources, the router preserves routing symmetry for valid paths without unnecessarily limiting resource utilization across the entire routing fabric.
Data Source
AI summary
A method of limiting the routing resources of an integrated circuit (IC) that are available for use when routing multi-fanout nets can include selecting a multi-fanout net comprising a source and a plurality of loads and identifying each region of the IC which does not include at least one of the plurality of loads. Each of the regions can have a defined geometry. A type of routing resource can be selected which has a physical orientation with respect to the IC that corresponds to the geometry of the regions of the IC. Each routing resource of the selected type that is located within a region of the IC which does not include at least one of the plurality of loads can be excluded from consideration when routing the multi-fanout net.