report_worst_slack returns INF

[xiaosinju]

I have run the following script:

read_lef ispd19_test6.input.lef
read_def ispd19_test6.input.def
set thread_count 8
global_route
detailed_route
write_db route.db
report wns
>> wns 0
report tns
>> tns 0
report worst_slack
>> worst slack INF

Did anything go wrong? How can I get correct metrics? Thanks a lot!

[vijayank88]

Do estimate parasitic and then report the metrics. Refer here: https://github.com/The-OpenROAD-Project/OpenROAD/blob/master/test/flow.tcl#L264-L280 @xiaosinju

[xiaosinju]

Thanks for your help!
I run the estimate_parasitics -global_routing and returns a bunch of warnings like Missing route to pin instxxxxxxxxxxx
Then the report_checks command returns the Segmentation fault:

Signal 11 received
Stack trace:
 0# 0x000055A64DAEAF9B in openroad
 1# 0x00007EFD2E9DB520 in /lib/x86_64-linux-gnu/libc.so.6
 2# sta::LibertyLibrary::inputThreshold(sta::RiseFall const*) const in openroad
 3# sta::RCDelayCalc::dspfWireDelaySlew(sta::Pin const*, float, float&, float&) in openroad
 4# sta::DmpCeffElmoreDelayCalc::loadDelay(sta::Pin const*, float&, float&) in openroad
 5# sta::GraphDelayCalc1::annotateLoadDelays(sta::Vertex*, sta::RiseFall const*, float const&, bool, sta::DcalcAnalysisPt const*, sta::ArcDelayCalc*) in openroad
 6# sta::GraphDelayCalc1::seedNoDrvrSlew(sta::Vertex*, sta::Pin const*, sta::RiseFall const*, sta::DcalcAnalysisPt*, sta::ArcDelayCalc*) in openroad
 7# sta::GraphDelayCalc1::seedDrvrSlew(sta::Vertex*, sta::ArcDelayCalc*) in openroad
 8# sta::GraphDelayCalc1::findDelays(int) in openroad
 9# sta::Sta::searchPreamble() in openroad
10# sta::Sta::totalNegativeSlack(sta::MinMax const*) in openroad
11# 0x000055A64DCDC644 in openroad
12# TclNRRunCallbacks in /lib/x86_64-linux-gnu/libtcl8.6.so
13# 0x00007EFD32874028 in /lib/x86_64-linux-gnu/libtcl8.6.so
14# Tcl_EvalEx in /lib/x86_64-linux-gnu/libtcl8.6.so
15# Tcl_Eval in /lib/x86_64-linux-gnu/libtcl8.6.so
16# ord::tclAppInit(Tcl_Interp*) in openroad
17# Tcl_MainEx in /lib/x86_64-linux-gnu/libtcl8.6.so
18# main in openroad
19# 0x00007EFD2E9C2D90 in /lib/x86_64-linux-gnu/libc.so.6
20# __libc_start_main in /lib/x86_64-linux-gnu/libc.so.6
21# _start in openroad
Segmentation fault (core dumped)

How to fix this? Thanks again for your gentleness and patience!

[vijayank88]

Please explore this flow for RTL-GDSII : https://github.com/The-OpenROAD-Project/OpenROAD-flow-scripts
Otherwise you need to provide a test case and script to reproduce or check at our end.

[xiaosinju]

Thanks! Actually I have explored ORFS for oevr a week and turned back to the OR project.
I'm totally new to this area and want to examine the timing performance like WNS or TNS of ISPD18 and 19 benchmark.
But the ORFS document seems not providing a script for such format inputs.
Could you please offer some instructions?

[vijayank88]

Sorry. I do not have experience with ISPD benchmark. @maliberty could you help on this?

[vijayank88]

Check this CI resullts: https://jenkins.openroad.tools/blue/organizations/jenkins/OpenROAD-Nightly-Public/detail/OpenROAD-Nightly-Public/1185/pipeline/213

[maliberty]

This is a routing test case and has no timing information (no .lib or .sdc). What are you trying to accomplish?

[xiaosinju]

That's right! Thank you very much for your help, and I will turn to other datasets for timing performance evaluation.

[xiaosinju]

I further turn to the congestion metric using ISPD15 benchmark. The global route stage successes, but the output congestion report is an empty file:

openroad> read_lef ispd19_test6.input.lef
openroad> read_def ispd19_test6.input.def
openroad> set_thread 8
openroad> global_route -congestion_report_file report_file.rpt -verbose
[INFO GRT-0020] Min routing layer: Metal1
[INFO GRT-0021] Max routing layer: Metal9
[INFO GRT-0022] Global adjustment: 0%
[INFO GRT-0023] Grid origin: (0, 0)
[INFO GRT-0043] No OR_DEFAULT vias defined.
[INFO GRT-0088] Layer Metal1  Track-Pitch = 0.1000  line-2-Via Pitch: 0.1000
[INFO GRT-0088] Layer Metal2  Track-Pitch = 0.1000  line-2-Via Pitch: 0.1000
[INFO GRT-0088] Layer Metal3  Track-Pitch = 0.1000  line-2-Via Pitch: 0.1000
[INFO GRT-0088] Layer Metal4  Track-Pitch = 0.1000  line-2-Via Pitch: 0.1000
[INFO GRT-0088] Layer Metal5  Track-Pitch = 0.1500  line-2-Via Pitch: 0.1100
[INFO GRT-0088] Layer Metal6  Track-Pitch = 0.2000  line-2-Via Pitch: 0.1500
[INFO GRT-0088] Layer Metal7  Track-Pitch = 0.2000  line-2-Via Pitch: 0.1650
[INFO GRT-0088] Layer Metal8  Track-Pitch = 0.2000  line-2-Via Pitch: 0.2000
[INFO GRT-0088] Layer Metal9  Track-Pitch = 1.0000  line-2-Via Pitch: 0.2000
[INFO GRT-0019] Found 0 clock nets.
[INFO GRT-0001] Minimum degree: 2
[INFO GRT-0002] Maximum degree: 1314
[INFO GRT-0003] Macros: 16
[INFO GRT-0004] Blockages: 6806721

[INFO GRT-0053] Routing resources analysis:
          Routing      Original      Derated      Resource
Layer     Direction    Resources     Resources    Reduction (%)
---------------------------------------------------------------
Metal1     Vertical     11986725       4325352          63.92%
Metal2     Horizontal   11986725       6412381          46.50%
Metal3     Vertical     11986725       7418829          38.11%
Metal4     Horizontal   11986725       7423116          38.07%
Metal5     Vertical      7991150       4807805          39.84%
Metal6     Horizontal    5593805       3316595          40.71%
Metal7     Vertical      5593805       5444456          2.67%
Metal8     Horizontal    5593805       5578624          0.27%
Metal9     Vertical       799115        799092          0.00%
---------------------------------------------------------------

[INFO GRT-0101] Running extra iterations to remove overflow.
[INFO GRT-0197] Via related to pin nodes: 806169
[INFO GRT-0198] Via related Steiner nodes: 114002
[INFO GRT-0199] Via filling finished.
[INFO GRT-0111] Final number of vias: 1224633
[INFO GRT-0112] Final usage 3D: 8035595

[INFO GRT-0096] Final congestion report:
Layer         Resource        Demand        Usage (%)    Max H / Max V / Total Overflow
---------------------------------------------------------------------------------------
Metal1         4325352        361069            8.35%             0 /  0 /  0
Metal2         6412381       1743225           27.19%             0 /  0 /  0
Metal3         7418829       1524316           20.55%             0 /  0 /  0
Metal4         7423116        497032            6.70%             0 /  0 /  0
Metal5         4807805        120901            2.51%             0 /  0 /  0
Metal6         3316595         50044            1.51%             0 /  0 /  0
Metal7         5444456         60764            1.12%             0 /  0 /  0
Metal8         5578624          4261            0.08%             0 /  0 /  0
Metal9          799092            84            0.01%             0 /  0 /  0
---------------------------------------------------------------------------------------
Total         45526250       4361696            9.58%             0 /  0 /  0

[INFO GRT-0018] Total wirelength: 8034628 um
[INFO GRT-0014] Routed nets: 179703

How can I get horizontal and vertical congestion from such flow?

[maliberty]

The congestion report is for errors that can't be resolved. See https://github.com/The-OpenROAD-Project/OpenROAD/tree/master/src/gui#heat-maps to dump the raw data

[xiaosinju]

Thanks a lot! I've been able to dump raw data of the congestion heat map. But how to produce the data in the map so that I can get the Max H-Congestion or Max V-Congestion? I other words, how are these metrics Max H, Max V defined?

[maliberty]

Congestion is demand - resource. You take the max over all gcells to get the max value. H/V are just directions.