Incremental Place and Routing for Partially Routed Circuit Designs
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Solution Overview
Problem
The existing place-and-route processes for programmable integrated circuits are time-consuming and inefficient, especially when only a small portion of the design changes, as they often require rerouting unchanged signals to accommodate modified signals, leading to congestion and increased processing time.
Innovation Solution
A processor-implemented method that identifies and reroutes unmodified signals with a high ratio of modified to unmodified signals, applying routing constraints to prevent rerouting of unmodified signals and optimizing signal propagation delays and wire usage, allowing for partial routing while preserving previous routing constraints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the entire place-and-route process is repeated when design changes occur, then complete routing optimization is achieved, but processing time increases significantly
Solution Approach 1:
The patent segments the routing process into two distinct phases: a detailed routing phase for modified signals and a relaxed routing phase for unmodified signals. This segmentation allows the system to perform complete optimization only where needed while using simpler, faster routing for unchanged portions, thereby reducing overall processing time while maintaining routing quality.
Solution Approach 2:
The patent applies different routing strategies to different parts of the design based on their modification status. Modified signals receive detailed routing optimization, while unmodified signals receive relaxed routing that preserves previous constraints. This local differentiation ensures optimization is applied only where necessary, reducing unnecessary processing time.
2Loss of time
If routing constraints are applied to preserve unmodified signals, then routing time is reduced, but congestion may occur when modified signals cannot be routed without rerouting unmodified signals
Solution Approach 1:
The patent implements dynamic routing constraint management where the system can adjust the strictness of constraints based on congestion conditions. When congestion is detected and modified signals cannot be routed without rerouting unmodified signals, the system dynamically relaxes constraints on selected unmodified signals to resolve the congestion issue, balancing time savings with routing feasibility.
Solution Approach 2:
The patent changes the routing constraint parameters dynamically based on the routing state. When congestion occurs, the system modifies constraint parameters (such as allowing rerouting of previously constrained signals) to enable successful routing of modified signals, thereby maintaining routing time benefits while avoiding complete routing failure.
3Stability of the object's composition
If routing software attempts to avoid rerouting unchanged signals, then preservation of previous routing is maintained, but processing time increases due to wasted effort
Solution Approach 1:
The patent applies partial routing preservation by selectively constraining only those unmodified signals that are likely to cause congestion, rather than preserving all unmodified signal routes. This partial action approach maintains routing stability where beneficial while avoiding unnecessary processing time spent on signals that don't contribute to congestion issues.
Data Source
AI summary
In one embodiment of the invention, a processor-implemented method is provided for routing of a partially routed circuit design. Modified signals of the partially routed circuit design are determined. A first set of routing constraints are applied by the processor to the unmodified signals of the circuit design. For each logic block of the circuit design, the number of the modified signals and the number of the unmodified signals connected to the logic block are determined. In response to one of the logic blocks having a ratio of the number of modified signals to the number of unmodified signals greater than a threshold ratio, the routing constraints are removed by the processor from one or more of the unmodified signals of the one of the logic blocks. The partially routed circuit design is then routed by the processor according to the remaining routing constraints, and the resulting netlist is stored.