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I was just looking at PL_DIAMOND_SEARCH_HEIGHT was removed as a parameter. This was previously neede...
# openlane
m
I was just looking at PL_DIAMOND_SEARCH_HEIGHT was removed as a parameter. This was previously needed to allow legalization with big macros. The comments say that the new default is "height*5", is that the height of the biggest macro or a standard cell? If it's a cell, this is a big problem. @User
It seems that this was observed as a problem back in August when it was removed: https://skywater-pdk.slack.com/archives/C016H8WJMBR/p1629299836114100
d
I'm... sorry, where was that comment?
m
@User what do you mean? I linked the prior message above as well as my issue at the top of this thread.
d
The comments say that the new default is "height*5",
Where is that stated? The commit description?
m
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Removed: Specifies the diamond search height used for legalizing the cells during detailed placement. The search width is calculated internally as heigh*5. For designs that contain big macros, increasing this value to above 400 will allow for more search space and more potentail for successful legalization.
d
It's removed, so I wouldn't count on this documentation for much other than knowing that it's removed. I would open an issue against OpenROAD.
m
I get a lot of errors with legalization and overlapping cells. I'm assuming it is because of this.
Isn't that an OpenLane parameter though?
@User Do you know whether this would be an issue in OpenRoad?
d
It was passed on to OpenROAD previously, but the OpenROAD app officially never exposed the diamond search height variable. When it stopped working, we removed it. If we were to re-add it, it would need to be exposed in OpenROAD first. OpenDP specifically.
n
I’m adding 
detailed_placement -max_displacement 2000
in scripts/openroad/or_opendp.tcl to fix the overlapping (near macros) issue
👍 1
m
@User This option is really needed for P&R with macros. It used to exist back in v0.17 of openlane: detailed_placement -diamond_search_height $::env(PL_DIAMOND_SEARCH_HEIGHT) (in scripts/openroad/or_opendp.tcl). Otherwise, antennas and filler overlapping macros cannot be fixed.
How should this issue be submitted?
d
I'm not disagreeing, but you'd have to make the case upstream to https://github.com/The-OpenROAD-Project/OpenROAD/issues. Once the variable is properly surfaced there, I'd be happy to pass it along.
Just something along the lines of a customizable diamond search height for OpenDP.
m
I don't see how anyone can complete a design with macros without this...
I can confirm that hacking it back in and using diodes+filler works now.
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