#251 New RCX tables show significant increase in parasitic capacitances New issue created by antonblanchard I'm seeing a 2-3x increase in parasitic capacitances when testing the old RCX tables vs the new ones. I know the old ones are suspect, but I just wanted to make sure this large an increase was expected. If the new ones are correct, we will need to update the capacitance estimates the resizer uses, so it has a better chance at fixing setup and hold violations. Test case is here: rcx-old-vs-new.tar.gz. rcx.tcl creates the SPEF files, sta.tcl does the timing analysis. In the test case I dump one of the longest paths which goes from 8.53 ns to 13.91 ns with the new tables:

Startpoint: _617_ (rising edge-triggered flip-flop clocked by clk)
Endpoint: _357_ (rising edge-triggered flip-flop clocked by clk)
Path Group: clk
Path Type: max

Fanout     Cap    Slew   Delay    Time   Description
-----------------------------------------------------------------------------
                          0.00    0.00   clock clk (rise edge)
                          0.00    0.00   clock source latency
                  0.39    0.29    0.29 ^ clk (in)
     1    0.09                           clk (net)
                  0.39    0.00    0.29 ^ clkbuf_0_clk/A (sky130_fd_sc_hd__clkbuf_16)
                  0.10    0.28    0.57 ^ clkbuf_0_clk/X (sky130_fd_sc_hd__clkbuf_16)
     4    0.08                           clknet_0_clk (net)
                  0.10    0.00    0.57 ^ clkbuf_2_2_0_clk/A (sky130_fd_sc_hd__clkbuf_8)
                  0.22    0.29    0.86 ^ clkbuf_2_2_0_clk/X (sky130_fd_sc_hd__clkbuf_8)
     4    0.13                           clknet_2_2_0_clk (net)
                  0.22    0.01    0.87 ^ clkbuf_4_10__f_clk/A (sky130_fd_sc_hd__clkbuf_16)
                  0.15    0.28    1.15 ^ clkbuf_4_10__f_clk/X (sky130_fd_sc_hd__clkbuf_16)
    10    0.14                           clknet_4_10__leaf_clk (net)
                  0.15    0.01    1.17 ^ clkbuf_leaf_98_clk/A (sky130_fd_sc_hd__clkbuf_16)
                  0.03    0.16    1.32 ^ clkbuf_leaf_98_clk/X (sky130_fd_sc_hd__clkbuf_16)
     2    0.01                           clknet_leaf_98_clk (net)
                  0.03    0.00    1.32 ^ _617_/CLK (sky130_fd_sc_hd__dfxtp_2)
                  0.34    0.54    1.87 ^ _617_/Q (sky130_fd_sc_hd__dfxtp_2)
     3    0.07                           a_registered[1] (net)
                  0.34    0.01    1.88 ^ repeater1205/A (sky130_fd_sc_hd__buf_4)
                  0.17    0.30    2.18 ^ repeater1205/X (sky130_fd_sc_hd__buf_4)
     9    0.06                           net1205 (net)
                  0.17    0.01    2.18 ^ U$$3/A (sky130_fd_sc_hd__and2_1)
                  0.05    0.16    2.34 ^ U$$3/X (sky130_fd_sc_hd__and2_1)
     1    0.00                           t (net)
                  0.05    0.00    2.34 ^ U$$4/B1 (sky130_fd_sc_hd__a32o_1)
                  0.29    0.31    2.64 ^ U$$4/X (sky130_fd_sc_hd__a32o_1)
     4    0.03                           sel_0 (net)
                  0.29    0.00    2.64 ^ repeater447/A (sky130_fd_sc_hd__buf_4)
                  0.22    0.32    2.97 ^ repeater447/X (sky130_fd_sc_hd__buf_4)
     9    0.08                           net447 (net)
                  0.22    0.01    2.98 ^ repeater445/A (sky130_fd_sc_hd__clkbuf_4)
                  0.20    0.32    3.30 ^ repeater445/X (sky130_fd_sc_hd__clkbuf_4)
     9    0.06                           net445 (net)
                  0.20    0.01    3.30 ^ repeater443/A (sky130_fd_sc_hd__buf_4)
                  0.29    0.34    3.65 ^ repeater443/X (sky130_fd_sc_hd__buf_4)
     9    0.11                           net443 (net)
                  0.29    0.02    3.67 ^ repeater442/A (sky130_fd_sc_hd__buf_4)
                  0.15    0.28    3.94 ^ repeater442/X (sky130_fd_sc_hd__buf_4)
     7    0.05                           net442 (net)
                  0.15    0.00    3.94 ^ U$$120/A2 (sky130_fd_sc_hd__a22o_1)
                  0.07    0.18    4.13 ^ U$$120/X (sky130_fd_sc_hd__a22o_1)
     1    0.01                           t$4498 (net)
                  0.07    0.00    4.13 ^ U$$121/A (sky130_fd_sc_hd__xor2_1)
                  0.08    0.09    4.22 v U$$121/X (sky130_fd_sc_hd__xor2_1)
     1    0.01                           booth_b0_m57 (net)
                  0.08    0.00    4.22 v dadda_fa_0_57_0/A (sky130_fd_sc_hd__fa_1)
                  0.10    0.48    4.70 v dadda_fa_0_57_0/COUT (sky130_fd_sc_hd__fa_1)
     1    0.01                           c$18 (net)
                  0.10    0.00    4.70 v dadda_fa_1_58_7/A (sky130_fd_sc_hd__fa_1)
                  0.13    0.53    5.24 v dadda_fa_1_58_7/COUT (sky130_fd_sc_hd__fa_1)
     1    0.01                           c$512 (net)
                  0.13    0.00    5.24 v dadda_fa_2_59_2/CIN (sky130_fd_sc_hd__fa_1)
                  0.10    0.51    5.75 v dadda_fa_2_59_2/SUM (sky130_fd_sc_hd__fa_1)
     1    0.01                           s$1454 (net)
                  0.10    0.00    5.75 v dadda_fa_3_59_3/A (sky130_fd_sc_hd__fa_1)
                  0.13    0.58    6.33 v dadda_fa_3_59_3/SUM (sky130_fd_sc_hd__fa_1)
     1    0.01                           s$2338 (net)
                  0.13    0.00    6.33 v dadda_fa_4_59_2/CIN (sky130_fd_sc_hd__fa_1)
                  0.13    0.50    6.83 v dadda_fa_4_59_2/COUT (sky130_fd_sc_hd__fa_1)
     1    0.02                           c$3073 (net)
                  0.13    0.00    6.83 v dadda_fa_5_60_0/CIN (sky130_fd_sc_hd__fa_2)
                  0.14    0.49    7.31 v dadda_fa_5_60_0/COUT (sky130_fd_sc_hd__fa_2)
     1    0.03                           c$3664 (net)
                  0.14    0.00    7.31 v dadda_fa_6_61_0/A (sky130_fd_sc_hd__fa_1)
                  0.23    0.73    8.04 ^ dadda_fa_6_61_0/SUM (sky130_fd_sc_hd__fa_1)
     1    0.02                           s$4049 (net)
                  0.23    0.00    8.05 ^ dadda_fa_7_61_0/CIN (sky130_fd_sc_hd__fa_1)
                  0.08    0.48    8.53 v dadda_fa_7_61_0/SUM (sky130_fd_sc_hd__fa_1)
     1    0.00                           s$4306 (net)
                  0.08    0.00    8.53 v _357_/D (sky130_fd_sc_hd__dfxtp_1)
                                  8.53   data arrival time

New RCX tables: ``` Startpoint: 617 (rising edge-triggered flip-flop clocked by clk) Endpoint: 357 (rising edge-triggered flip-flop clocked by clk) Path Group: clk Path Type: max Fanout Cap Slew Delay Time Description ----------------------------------------------------------------------------- 0.00 0.00 clock clk (rise edge) 0.00 0.00 clock source latency 0.93 0.69 0.69 ^ clk (in) 1 0.21 clk (net) 0.93 0.00 0.69 ^ clkbuf_0_clk/A (sky130_fd_sc_hd__clkbuf_16) 0.24 0.46 1.15 ^ clkbuf_0_clk/X (sky130_fd_sc_hd__clkbuf_16) 4 0.23 clknet_0_clk (net) 0.24 0.01 1.16 ^ clkbuf_2_2_0_clk/A (sky130_fd_sc_hd__clkbuf_8) 0.58 0.58 1.74 ^ clkbuf_2_2_0_clk/X (sky130_fd_sc_hd__clkbuf_8) 4 0.34 clknet_2_2_0_clk (net) 0.58 0.04 1.78 ^ clkbuf_4_10__f_clk/A (sky130_fd_sc_hd__clkbuf_16) 0.33 0.48 2.26 ^ clkbuf_4_10__f_clk/X (sky130_fd_sc_hd__clkbuf_16) 10 0.32 clknet_4_10__leaf_clk (net) 0.33 0.03 2.29 ^ clkbuf_leaf_98_clk/A (sky130_fd_sc_hd__clkbuf_16) 0.04 0.21 2.50 ^ clkbuf_leaf_98_clk/X (sky130_fd_sc_hd__clkbuf_16) 2 0.01 clknet_leaf_98_clk (net) 0.04 0.00 2.50 ^ _617_/CLK (sky130_fd_sc_hd__dfxtp_2) 1.28 1.21 3.71 ^ _617_/Q (sky130_fd_sc_hd__dfxtp_2) 3 0.26 a_registered[1] (net) 1.28 0.04 3.76 ^ repeater1205/A (sky130_fd_sc_hd__b… RTimothyEdwards/open_pdks