Crosstalk Driven Routing Crosstalk Driven Routing Resource AssignmentResource Assignment

Hailong Yao; Qiang Zhou;Xianlong Hong; Yici Cai;

EDA Lab., Dept. of Computer Science Tsinghua University, Beijing, China

ISCAS’04

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AgendaAgenda

Introduction Preliminaries Crosstalk Model The CDRRA Algorithm Experimental Results Conclusions

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AgendaAgenda

IntroductionIntroduction Preliminaries Crosstalk Model The CDRRA Algorithm Experimental Results Conclusions

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IntroductionIntroduction

Routing Global Routing Detailed Routing

Crosstalk Driven Routing Global Routing Stage Detailed Routing Stage Intermediate Stage

Track Assignment Cross Point Assignment

Estimation of crosstalk is

more accurate but flexibility to control is restricted

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AgendaAgenda

Introduction PreliminariesPreliminaries Crosstalk Model The CDRRA Algorithm Experimental Results Conclusions

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Preliminaries(1/3)Preliminaries(1/3)

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Preliminaries(2/3)Preliminaries(2/3)

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Preliminaries(3/3)Preliminaries(3/3)

Crosstalk Aggressor Victim

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AgendaAgenda

Introduction Preliminaries Crosstalk ModelCrosstalk Model The CDRRA Algorithm Experimental Results Conclusions

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Crosstalk Model(1/2)Crosstalk Model(1/2)

ij

jiij

ijijc

d

wwd

lfjiC

21

1,

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Crosstalk Model(2/2)Crosstalk Model(2/2)

Sensitivity rate A given parameter

Sensitivity matrix S If Neti is sensitive to Netj, Sij = 1.

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AgendaAgenda

Introduction Preliminaries Crosstalk Model The CDRRA AlgorithmThe CDRRA Algorithm Experimental Results Conclusions

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CostCost

Layer Cost Obstacle Cost Net Length Cost

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CDRRA AlgorithmCDRRA Algorithm(1) Read in the sensitivity rate and construct the crosstalk graph (XG).(2) For all the horizontal and vertical slices, DO(3) Construct the interval graph (IG).(4) Construct the real crosstalk graph (RXG).(5) Construct the tracks’ adjacency graph (TAG).(6) Construct the cost matrix for the assignments of net segments

onto the routing tracks.(7) Compute the maximum clique in RXG and the maximum

independent set in TAG. Calculate the minimum cost assignment solution using the linear assignment algorithm.

(8) Update IG, RXG, TAG and the cost matrix according to the assignment results. If RXG is NULL, then go to (9), else go to

(7).(9) Compute the maximum clique from IG and assign the net

segments onto the remaining routing tracks using the same algorithm until all the net segments are assigned or the routing tracks are not available.

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ExampleExample

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Crosstalk Graph (XG)Crosstalk Graph (XG)

BACK

V: set of all the nets.

Exg: sensitive relationship.

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Interval Graph (IG)Interval Graph (IG)

BACK

V: set of net segments inside

the current slice. Eig: overlap informatio

n.

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Real Crosstalk Graph Real Crosstalk Graph (RXG)(RXG)

BACK

V: set of net segments. Erxg: overlap length ex

ceeds MAXOL

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Track’s Adjacency Graph Track’s Adjacency Graph (TAG)(TAG)

BACK

V: set of routing tracks.

Etag: adjacency information

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Assignment ResultsAssignment Results

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AgendaAgenda

Introduction Preliminaries Crosstalk Model The CDRRA Algorithm Experimental ResultsExperimental Results Conclusions

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Experimental ResultsExperimental Results

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AgendaAgenda

Introduction Preliminaries Crosstalk Model The CDRRA Algorithm Experimental Results ConclusionsConclusions

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ConclusionsConclusions

Crosstalk driven routing in intermediate stage: Track Assignment Stage.

Fully utilizes the routing resources. Improvement Ratio: 37.5% - 69.8%.