A Practical Way to Do Netlist ECO & Debug

GOF beats Conformal ECO Case 1


The test case is extracted from a large hierarchical design. RTL changes affect 6 flops and 6 output ports. GOF auto ECO uses 24 cells 4.7 in area to fix the logic, while conformal ECO uses 76 cells 20.3 in area to fix the logic. To be fair in comparison, all cells in ECO use driver 'D0'.

Results Comparison

ECO Result Total Cells Non-Buffer Invert Buffer Area
GOF 24 7 14 3 4.7
Conformal ECO 76 62 14 0 20.3

Files in ECO

  • gof_patch.v ----------------- GOF patch file, 24 cells
  • cfm_eco_patch_1.v ------- Conformal ECO patch file, 76 cells
  • imp.v -------------------------- Implementation netlist
  • ref.v --------------------------- Reference netlist
  • mp16.lib ---------------------- Liberty file. Warning! Since timing information is removed, the file can not be used in Synthesis
  • eco.gpl -------------------------- GOF ECO script

Comparison on Schematic

 GOF generates a patch having 24 gates in total.

Figure 1 GOF ECO patch

While Conformal ECO generates a big patch with total 76 gates.

Figure 2 Conformal ECO patch

GOF command line

The files can be downloaded to reproduce the result

gof -lib mp16.lib imp.v -ref ref.v -run eco.gpl


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