Can I ask global route to fail early?

[oharboe]

@nerriav Global routing takes very little time for the project I am working on. However, when I make changes, these sometimes can make global routing impossible and I have to tweak my change.

When global routing fails, it doesnt fail quickly, it just runs "forever"(hours compared to minutes) before it ultimately fails.

Can I adjust a setting such that global route fails quickly so that I dont waste server build resources and I can quickly load the routing congestion report in the DRC viewer to drill down to the problem?

[rovinski]

In OR you can use the -congestion_interations argument which translates to GLOBAL_ROUTE_ARGS=" -congestion_iterations X " in ORFS. X is a positive integer. The default is 100.

[oharboe]

What should I look for in the log when choosing a new value?

Try with different values?

The only reference to itrations I found in the log:

[INFO GRT-0101] Running extra iterations to remove overflow.
[deleted]
Elapsed time: 2:22.98[h:]min:sec. CPU time: user 137.41 sys 5.50 (99%). Peak memory: 13555660KB.

So less than 3 minutes...

[maliberty]

Smaller values will be faster but try less hard to resolve the congestion. You'll have to experiment to see the tradeoff.

[oharboe]

I see. Thanks!

[oharboe]

Syntax subtleties... export GLOBAL_ROUTE_ARGS="-congestion_iterations 10 -verbose", failed with [ERROR STA-0402] global_route -congestion_iterations 10 -verbose is not a known keyword or flag.

export GLOBAL_ROUTE_ARGS=-congestion_iterations 10 -verbose worked...

It is still stuck on:

[INFO GRT-0101] Running extra iterations to remove overflow.

With export GLOBAL_ROUTE_ARGS=-congestion_iterations 2 -verbose it fails after 2:30 minutes.

I'll see how high I can make it until it "runs forever". If it fails after 10 minutes, then I have something I can try out. If there is nothing wrong, I would expect it to complete in ca. 3 minutes.

I'm curious if 10 iterations is enough for all the designs under test... The-OpenROAD-Project/OpenROAD-flow-scripts#1076