global routing failing

[DarylK78]

Running a design with 60K placeable gates, seeing routing congestion issues and not sure how to debug.

I am unable to attach my operoad.zip as it say "is not included in the list"

[maliberty]

Perhaps it dislikes the extension or you have the issue in https://github.com/github/hub/issues/1479

Try changing it to .zip1 and see if it works.

[DarylK78]

Actually seems to be an issue with the filesize, is there a max on how large files to upload can be in the comments?

[maliberty]

Probably but idk. You can always put the file in some cloud storage and provide a link (eg google drive, dropbucket).

[vijayank88]

@DarylK78 Yes there is file size limitation to attach here. If you're facing issue, upload file in your personal repo and share link here.

[DarylK78]

I was able to get the archive to a manageable size, this was run with the PL_TARGET_DENSITY at 0.25 and the FP_CORE_UTIL at 25. Still seeing too much congestion

openroad.zip

[vijayank88]

@DarylK78 Core has enough free space. But still I'm seeing high congestion near macro and std cell area as well.

set ::env(PL_MACRO_CHANNEL) "10 10"
set ::env(PL_MACRO_HALO) "10 10"

Can you try this setting in your OpenLane config.tcl and re-run the flow.

Possible try to place macros manullay based on functionality.

[eder-matheus]

I see this in the congestion map: Perhaps the placement density is too large? The global router ends with high congestion even when I don't use the resources adjustments.

[mousaq92]

How do you get these heat maps in the GUI?

[eder-matheus]

How do you get these heat maps in the GUI?

In the Display Control, go to Heat Maps and select what heat map you want to visualize. In the figure below, I'm showing only the routing congestion heat map:

[mousaq92]

Thanks.

[Sya0]

I see this in the congestion map: Perhaps the placement density is too large? The global router ends with high congestion even when I don't use the resources adjustments.

@mousaq92, @eder-matheus Sorry to interrupt but is this klayout?

[vijayank88]

@Sya0 its OpenROAD GUI Command to use: openroad -gui

[DarylK78]

I took the advice to a add macro channels, and now it is able to global route but runs into issues with diodes

See latest run here:

openroad.zip .

[luis201420]

@DarylK78 Could you upload the tarball containing the stage before the global placement?

[DarylK78]

This one is the tarball of the placement step I believe

openroad.zip

[DarylK78]

This one runs the init_floorplan

floorplan.zip

[eder-matheus]

Thanks very much, @DarylK78!

[ravi-varadarajan]

I examined the congested areas and it is due the dense concentration of combinational cells (4 input nor or ao22/oa22) in the congested area. You should be able to resolve this by using non zero global and detailed placement padding. We will also examine the init_floorplan tarball -- thanks

[eder-matheus]

I took the advice to a add macro channels, and now it is able to global route but runs into issues with diodes

See latest run here:

openroad.zip .

The latest version of OpenROAD have a fix for the diodes issue. Can you try that?

[DarylK78]

I was able to get it to route by using DIODE_STRATEGY 4 and turning off fill.

I'm also seeing a lot of slew violations which might be affecting the diode issue (nets are too long). I will go back to placement and try some additional things, and also attempt to use the latest version of openroad as well.

[vijayank88]

Closing as resolved based on user comment.