1 / 29

Spare-Cell-Aware Multilevel Analytical Placement

Zhe-Wei Jiang, Meng-Kai Hsu, Yao-Wen Chang and Kai-Yuan Chao From DAC2009. Spare-Cell-Aware Multilevel Analytical Placement. Outline. Background Problem formulation Analytical placement framework Integrate spare-cell consideration to AP Multilevel spare-cell-aware insertion

azra
Download Presentation

Spare-Cell-Aware Multilevel Analytical Placement

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Zhe-Wei Jiang, Meng-Kai Hsu, Yao-Wen Chang and Kai-Yuan Chao From DAC2009 Spare-Cell-Aware Multilevel Analytical Placement

  2. Outline • Background • Problem formulation • Analytical placement framework • Integrate spare-cell consideration to AP • Multilevel spare-cell-aware insertion • Experimental result

  3. Placement

  4. Spare Cell

  5. Introduction • There are two common ways to performing post-silicon debugging. • Metal fix : reuse the transistor masks and change only the metal layer masks. • FIB(Focus Ion Beam): cut unwanted electrical connections, or to deposit conductive material to make a connection after chip is manufactured Both of them require spare cells insertion

  6. Outline • Background • Problem formulation • Analytical placement framework • Integrate spare-cell consideration to AP • Multilevel spare-cell-aware insertion • Experimental result

  7. Problem formulation • Given a hypergraph H = (V,E) • Let V= be blocks E= be nets We intend to determine the optimal positions of movable blocks such that the wirelength is minimized, and there is no overlap among blocks.

  8. Previous Work • PostSpare[26][22] : inserting spare cells after design placement. • UniSpare[10]: place spare cells among the chip uniformly before placement.

  9. Outline • Background • Problem formulation • Analytical placement framework • Integrate spare-cell consideration to AP • Multilevel spare-cell-aware insertion • Experimental result

  10. Multi-level framwork

  11. Flow chart Upper-level Uncoarsening stage Lower-level uncoarsening stage

  12. Analytical Placement Framework(global placement)

  13. Log-sum-exp wirelength Smooth the function When is small, log-sum-exp wirelength is close to the HPWL.

  14. Potential function Bell-shaped smooth function

  15. Solve Unconstraint programming Solve by conjugate gradient Apply quadratic penalty method. We solve a sequence of unconstrained minimization problem with increasing

  16. Outline • Background • Problem formulation • Analytical placement framework • Integrate spare-cell consideration to AP • Multilevel spare-cell-aware insertion • Experimental result

  17. Cluster Expansion • In most cases, the spare cell requirement is determined by designer’s experience. Designer need to set this parameter

  18. Density-Constraint Determination

  19. Outline • Background • Problem formulation • Analytical placement framework • Integrate spare-cell consideration to AP • Multilevel spare-cell-aware insertion • Experimental result

  20. Multilevel Spare Cell Insertion Top-down partition & spare cell allocation Partition according to block distribution 35:15 15:20 10:5 bottom-up spare cell position computation

  21. Determination of Optimal Spare Cell Positions • The optimal positions that minimize the avg distance form blocks to spare cells.

  22. Determination of Optimal Spare Cell Positions The sub-region usually contain less than 5 spare cell.

  23. Outline • Background • Problem formulation • Analytical placement framework • Integrate spare-cell consideration to AP • Multilevel spare-cell-aware insertion • Experimental result

  24. Experimental Result • Quality Comparison of Spare Cell Insertion IWLS 2005 benchmark

  25. Experimental Result • HPWL Comparison after Spare Cell Insertion

  26. Conclusions • The paper proposed the first spare-cell-aware analytical placement framework. • Experimental result have shown that this algorithm can achieve a much better solution quality of spare cell insertion than existing algorithms with only slight quality overhead.

More Related