The-OpenROAD-Project
Improve CTS skew and runtime
Description
unzip https://drive.google.com/file/d/1IKNjdXdUdjgcf1zjTXuyDntbyXLWgrO8/view?usp=sharing
./run-me-BoomTile-asap7-base.sh
OpenROAD v2.0-11428-g64228063b
[deleted]
[INFO CTS-0032] Stop criterion found. Max number of sinks is 15.
[INFO CTS-0035] Number of sinks covered: 4433.
[INFO CTS-0018] Created 5337 clock buffers.
[INFO CTS-0012] Minimum number of buffers in the clock path: 23.
[INFO CTS-0013] Maximum number of buffers in the clock path: 24.
[INFO CTS-0014] 1 clock nets were removed/fixed.
[INFO CTS-0015] Created 5336 clock nets.
[INFO CTS-0016] Fanout distribution for the current clock = 0:1, 1:3, 2:10, 3:34, 4:50, 5:43, 6:55, 7:51, 8:61, 9:57, 10:56, 11:36, 12:32, 13:24, 14:18, 15:16, 16:11, 17:11, 18:7, 19:4, 20:4, 21:5, 22:3, 23:2, 24:3, 25:3, 26:2, 27:1, 29:1, 30:4338..
[INFO CTS-0017] Max level of the clock tree: 9.
[INFO CTS-0098] Clock net "clock"
[INFO CTS-0099] Sinks 131199
[INFO CTS-0100] Leaf buffers 4430
[INFO CTS-0101] Average sink wire length 2221.56 um
[INFO CTS-0102] Path depth 23 - 24
[WARNING STA-0357] virtual clock clock_vir can not be propagated.
Warning: There are 540 unconstrained endpoints.
After ca. 1 minute, there is no further output for quite some time... 20 minutes?
==========================================================================
cts pre-repair report_design_area
--------------------------------------------------------------------------
Design area 985247 u^2 51% utilization.
[INFO RSZ-0058] Using max wire length 162um.
[INFO RSZ-0047] Found 62 long wires.
[INFO RSZ-0048] Inserted 98 buffers in 62 nets.
Warning: There are 540 unconstrained endpoints.
Then nothing for maybe another 20 minutes?
==========================================================================
cts post-repair report_design_area
--------------------------------------------------------------------------
Design area 985278 u^2 51% utilization.
Placement Analysis
---------------------------------
total displacement 12910.7 u
average displacement 0.0 u
max displacement 278.4 u
original HPWL 16326114.3 u
legalized HPWL 16466441.8 u
delta HPWL 1 %
Repair setup and hold violations...
TNS end percent 5
[INFO RSZ-0046] Found 17274 endpoints with hold violations.
No further output for a while...
Suggested Solution
No response
Additional Context
No response
How is this different from #4333 ?
One is a feature request for progress info, the other to speed up CTS.
@precisionmoon would you start by looking at the skew show in
(from https://github.com/The-OpenROAD-Project/OpenROAD-flow-scripts/discussions/1710) before we start on runtime.
with the current settings there are many buffers on the macros:
but if I add -obstruction_aware I see:
Some objects are now outside the die area which is wrong. Some are still on top of macros too.
PR 4383 should fix the issue of cells getting placed outside core area and cells on top of hardmacros.
@precisionmoon with #4459 and -obstruction_aware does the skew improve?
Worst skew remains at 58.56 immediately after CTS with and without -obstruction_aware, even after #4459. Clock clock Latency CRPR Skew core/fp_rename_stage/7310/CLK ^ 451.28 core/fp_rename_stage/freelist/45073/CLK ^ 392.72 0.00 58.56