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Timing Driven Incremental Placement-Based Optimization with Simultaneous Layer Assignment Disclosure Number: IPCOM000248724D
Publication Date: 2016-Dec-29
Document File: 2 page(s) / 29K

Publishing Venue

The Prior Art Database


Disclosed contribution is an enhancement that comprises an incremental congestion-aware layer assignment.

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Timing Driven Incremental Placement -Based Optimization with Simultaneous Layer Assignment

This disclosure addresses the design timing closure process in physical synthesis. Often, for timing challenged designs, the final results have timing critical paths that meander around and/or path delays dominated by interconnect delays. Even if such paths started out better after initial placement(s), subsequent churn may lead to sub-optimal path placement. In addition, critical region may very significantly shift or change. Paths that were initially less timing-critical and less optimally placed may become more critical.

The existing timing-driven placement algorithm provides free space-aware critical path smoothing. It is a what-you-see-is-what-you-get (WYSIWYG) approach, with no additional legalization needed. Timing on a path will be improved or be the same following trial and error with an incremental timing subsystem. This algorithm moves each box on the path in coordination with other boxes on the same path. It computes the ideal locations by treating a path as a whole and employs the Bezier curve method to produce similar effect as a multi-box movement. This approach moves multiple boxes on a path while resizing the power levels to adjust for load changes.

The novel contribution is an enhancement that comprises an incremental congestion-aware layer assignment.

The layer assignment operates on top of critical path smoothing. The critical path smoothing incurs placement chang...