Title
An analytical approach to placement legalization
Abstract
We present a method to achieve nearly legal placement while optimizing the traditional metrics in an analytical placement framework. A legalization penalty function term is added to the cost function of the placer. The purpose of this term is to remove overlaps and place cells into rows. The new term kicks in when global spreading cannot resolve overlaps any further. We study how this legalization term in placement helps to achieve better final placements when it is used in combination with wire-length driven analytical placement. Experimental results show that using this additional legalization cost term results in reduction of degradation of wire-length from 7.6% to 0.7% after discrete detailed placement. Optimization of wire-length along with the legalization term in placement shows 6% improvement in total wire-length on average, which if translated into timing is 48% of total negative slack. A further feature to control cell density helps reduce congestion by 33%.
Year
DOI
Venue
2008
10.1145/1366110.1366152
ACM Great Lakes Symposium on VLSI
Keywords
Field
DocType
placement spreading,legalization term,placement legalization,discrete detailed placement,additional legalization cost term,new term,analytical approach,analytical placement framework,analytical placement,legal placement,final placement,detailed placement,legalization penalty function term,placement shows,cost function,penalty function
Row,Mathematical optimization,Computer science,Legalization,Cell density,Penalty method
Conference
Citations 
PageRank 
References 
0
0.34
5
Authors
3
Name
Order
Citations
PageRank
Andrey Ayupov11127.12
Alexander Marchenko200.34
Vladimir Tiourin3332.03