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est: No parasitics update after remove_buffer

Open jhkim-pii opened this issue 1 month ago • 0 comments

Describe the bug

net1 -- buf -- net2

When a remove_buffers buf is executed for the buf, the net1 and net2 are merged into net1 and the resulting RC of net1 should change. But RC remains unchanged.

I found that the merged net1 was initially marked as dirty, but later it is cleared, which skips incremental global_routing.

Expected Behavior

Correct RC update after remove_buffers

Environment

-- The CXX compiler identification is GNU 13.3.0
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/g++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- OpenROAD version: v2.0-26171-g3113e7b0b1
-- System name: Linux
-- Compiler: GNU 13.3.0
-- Build type: RELEASE
-- Install prefix: /usr/local
-- C++ Standard: 17
-- C++ Standard Required: ON
-- C++ Extensions: OFF
-- The C compiler identification is GNU 13.3.0
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: /usr/bin/gcc - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Performing Test C_COMPILER_SUPPORTS__-Wall
-- Performing Test C_COMPILER_SUPPORTS__-Wall - Success
-- Performing Test CXX_COMPILER_SUPPORTS__-Wall
-- Performing Test CXX_COMPILER_SUPPORTS__-Wall - Success
-- Performing Test C_COMPILER_SUPPORTS__-Wno-array-bounds
-- Performing Test C_COMPILER_SUPPORTS__-Wno-array-bounds - Success
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-array-bounds
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-array-bounds - Success
-- Performing Test C_COMPILER_SUPPORTS__-Wno-nonnull
-- Performing Test C_COMPILER_SUPPORTS__-Wno-nonnull - Success
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-nonnull
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-nonnull - Success
-- Performing Test C_COMPILER_SUPPORTS__-Wno-maybe-uninitialized
-- Performing Test C_COMPILER_SUPPORTS__-Wno-maybe-uninitialized - Success
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-maybe-uninitialized
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-maybe-uninitialized - Success
-- Performing Test C_COMPILER_SUPPORTS__-Wno-format-overflow
-- Performing Test C_COMPILER_SUPPORTS__-Wno-format-overflow - Success
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-format-overflow
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-format-overflow - Success
-- Performing Test C_COMPILER_SUPPORTS__-Wno-unused-variable
-- Performing Test C_COMPILER_SUPPORTS__-Wno-unused-variable - Success
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-unused-variable
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-unused-variable - Success
-- Performing Test C_COMPILER_SUPPORTS__-Wno-unused-function
-- Performing Test C_COMPILER_SUPPORTS__-Wno-unused-function - Success
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-unused-function
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-unused-function - Success
-- Performing Test C_COMPILER_SUPPORTS__-Wno-write-strings
-- Performing Test C_COMPILER_SUPPORTS__-Wno-write-strings - Success
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-write-strings
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-write-strings - Success
-- Performing Test C_COMPILER_SUPPORTS__-Wno-sign-compare
-- Performing Test C_COMPILER_SUPPORTS__-Wno-sign-compare - Success
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-sign-compare
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-sign-compare - Success
-- Performing Test C_COMPILER_SUPPORTS__-Wno-deprecated
-- Performing Test C_COMPILER_SUPPORTS__-Wno-deprecated - Success
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-deprecated
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-deprecated - Success
-- Performing Test C_COMPILER_SUPPORTS__-Wno-c++11-narrowing
-- Performing Test C_COMPILER_SUPPORTS__-Wno-c++11-narrowing - Failed
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-c++11-narrowing
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-c++11-narrowing - Failed
-- Performing Test C_COMPILER_SUPPORTS__-Wno-register
-- Performing Test C_COMPILER_SUPPORTS__-Wno-register - Failed
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-register
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-register - Success
-- Performing Test C_COMPILER_SUPPORTS__-Wno-format
-- Performing Test C_COMPILER_SUPPORTS__-Wno-format - Success
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-format
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-format - Success
-- Performing Test C_COMPILER_SUPPORTS__-Wno-reserved-user-defined-literal
-- Performing Test C_COMPILER_SUPPORTS__-Wno-reserved-user-defined-literal - Failed
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-reserved-user-defined-literal
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-reserved-user-defined-literal - Failed
-- Performing Test C_COMPILER_SUPPORTS__-fpermissive
-- Performing Test C_COMPILER_SUPPORTS__-fpermissive - Failed
-- Performing Test CXX_COMPILER_SUPPORTS__-fpermissive
-- Performing Test CXX_COMPILER_SUPPORTS__-fpermissive - Success
-- Performing Test C_COMPILER_SUPPORTS__-x
-- Performing Test C_COMPILER_SUPPORTS__-x - Failed
-- Performing Test CXX_COMPILER_SUPPORTS__-x
-- Performing Test CXX_COMPILER_SUPPORTS__-x - Failed
-- Performing Test C_COMPILER_SUPPORTS__c++
-- Performing Test C_COMPILER_SUPPORTS__c++ - Failed
-- Performing Test CXX_COMPILER_SUPPORTS__c++
-- Performing Test CXX_COMPILER_SUPPORTS__c++ - Failed
-- Performing Test C_COMPILER_SUPPORTS__-Wno-unused-but-set-variable
-- Performing Test C_COMPILER_SUPPORTS__-Wno-unused-but-set-variable - Success
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-unused-but-set-variable
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-unused-but-set-variable - Success
-- Performing Test C_COMPILER_SUPPORTS__-std=c++17
-- Performing Test C_COMPILER_SUPPORTS__-std=c++17 - Failed
-- Performing Test CXX_COMPILER_SUPPORTS__-std=c++17
-- Performing Test CXX_COMPILER_SUPPORTS__-std=c++17 - Success
-- Performing Test C_COMPILER_SUPPORTS__-fno-exceptions
-- Performing Test C_COMPILER_SUPPORTS__-fno-exceptions - Success
-- Performing Test CXX_COMPILER_SUPPORTS__-fno-exceptions
-- Performing Test CXX_COMPILER_SUPPORTS__-fno-exceptions - Success
-- Found Python3: /usr/bin/python3.12 (found version "3.12.3") found components: Interpreter
-- Performing Test CMAKE_HAVE_LIBC_PTHREAD
-- Performing Test CMAKE_HAVE_LIBC_PTHREAD - Success
-- Found Threads: TRUE
-- TCL library: /usr/lib/x86_64-linux-gnu/libtcl.so
-- TCL header: /usr/include/tcl/tcl.h
-- TCL readline library: /usr/lib/x86_64-linux-gnu/libtclreadline.so
-- TCL readline header: /usr/include/x86_64-linux-gnu
-- Found SWIG: /usr/local/bin/swig (found suitable version "4.3.0", minimum required is "4.0")
-- Using SWIG >= 4.3.0 -flatstaticmethod flag for python
-- boost: 1.86.0
-- Found GTest: /usr/local/lib/cmake/GTest/GTestConfig.cmake (found version "1.13.0")
-- GTest: 1.13.0
-- Found Python3: /usr/include/python3.12 (found version "3.12.3") found components: Development Development.Module Development.Embed
-- Found ZLIB: /usr/lib/x86_64-linux-gnu/libz.so (found version "1.3")
-- spdlog: 1.15.0
-- Found BISON: /usr/bin/bison (found version "3.8.2")
-- Found Doxygen: /usr/bin/doxygen (found version "1.9.8") found components: doxygen dot
-- STA version: 2.7.0
-- STA git sha: d7cb9be1ca02eb7ac55048d5b9a3b9da5d1840dd
-- System name: Linux
-- Compiler: GNU 13.3.0
-- Build type: RELEASE
-- Build CXX_FLAGS: -O3 -DNDEBUG
-- Install prefix: /usr/local
-- Found FLEX: /usr/bin/flex (found version "2.6.4")
-- TCL library: /usr/lib/x86_64-linux-gnu/libtcl.so
-- TCL header: /usr/include/tcl/tcl.h
-- TCL readline library: /usr/lib/x86_64-linux-gnu/libtclreadline.so
-- TCL readline header: /usr/include/x86_64-linux-gnu/tclreadline.h
-- CUDD library: /usr/local/lib/libcudd.a
-- CUDD header: /usr/local/include/cudd.h
-- SSTA: 0
-- Found SWIG: /usr/local/bin/swig (found suitable version "4.3.0", minimum required is "3.0")
-- STA library: /workspace/ws4/OpenROAD-flow-scripts/tools/OpenROAD/build/libOpenSTA.a
-- STA executable: /workspace/ws4/OpenROAD-flow-scripts/tools/OpenROAD/build/sta
-- Found re2: /opt/or-tools/lib/cmake/re2/re2Config.cmake (found version "11.0.0")
-- Found Clp: /opt/or-tools/lib/cmake/Clp/ClpConfig.cmake (found version "1.17.7")
-- Found Cbc: /opt/or-tools/lib/cmake/Cbc/CbcConfig.cmake (found version "2.10.7")
-- Found SCIP: /opt/or-tools/lib/cmake/scip/scip-config.cmake (found version "9.0.0")
-- Found OpenMP_CXX: -fopenmp (found version "4.5")
-- Found OpenMP: TRUE (found version "4.5")
-- Found OR-Tools: /opt/or-tools/lib/cmake/ortools (version: 9.11.4210)
-- TCL library: /usr/lib/x86_64-linux-gnu/libtcl.so
-- TCL header: /usr/include/tcl/tcl.h
-- Found OpenMP_C: -fopenmp (found version "4.5")
-- Found OpenMP: TRUE (found version "4.5")
-- Found OpenMP: TRUE (found version "4.5")
-- GUI is enabled
-- Could NOT find VTune (missing: VTune_LIBRARIES VTune_INCLUDE_DIRS) 
-- TCL library: /usr/lib/x86_64-linux-gnu/libtcl.so
-- TCL header: /usr/include/tcl/tcl.h
-- Found Eigen3: /usr/local/share/eigen3/cmake/Eigen3Config.cmake (found version "3.4.1")
-- TCL readline enabled
-- Tcl Extended disabled
-- Python3 enabled

To Reproduce

Run the following test case.

FAIL

worst slack max -0.39
[INFO RSZ-0026] Removed 1 buffers.
worst slack max -0.37
worst slack max -0.37
worst slack max -0.31

PASS

worst slack max -0.39
[INFO RSZ-0026] Removed 1 buffers.
worst slack max -0.31
worst slack max -0.31
worst slack max -0.31

remove_buffers6.tcl

# Check RC update by incremental global routing after remove_buffer
source "helpers.tcl"
if { ![info exists repair_args] } {
  set repair_args {}
}

read_liberty Nangate45/Nangate45_typ.lib
read_lef Nangate45/Nangate45.lef
read_def remove_buffers6.def
initialize_floorplan -die_area "0 0 40 1200" \
  -core_area "0 0 40 1200" \
  -site FreePDK45_38x28_10R_NP_162NW_34O

source Nangate45/Nangate45.vars
source Nangate45/Nangate45.rc
source $tracks_file

create_clock -period 0.3 clk
set_propagated_clock clk

detailed_placement

source Nangate45/Nangate45.rc
# Intentionaly reduce RC so there is a large discrepancy between
# placement and global route parasitics.
set_wire_rc -resistance 0.0001 -capacitance 0.00001
set_routing_layers -signal $global_routing_layers
global_route
estimate_parasitics -global_routing

# 0. WNS - pre
report_worst_slack -max

#set_debug_level RSZ repair_setup 10
#set_debug_level RSZ opt_moves 10
#set_debug_level RSZ remove_buffer 10
#set_debug_level EST est_rc 10
#set_debug_level GRT incr 10

remove_buffers u5

# 1. WNS - after remove_buffer
report_worst_slack -max
estimate_parasitics -global_routing

# 2. WNS - after RC update
report_worst_slack -max

global_route
estimate_parasitics -global_routing

# 3. WNS - after redundant global routing
report_worst_slack -max

# WNS 1~3 should be the same

Relevant log output

Screenshots

No response

Additional Context

No response

jhkim-pii avatar Nov 17 '25 01:11 jhkim-pii