Hi All, I get following placement from the default...
# openlane
Hi All, I get following placement from the default hardening script of user_proj_example. Can an expert guide me how to relax this placement such that cells are more sparse. This design is too difficult to route.
I have had the same issue with the default script. You can try to disable PL_BASIC_PLACEMENT, enable PL_ROUTABILITY_DRIVEN and different values of PL_TARGET_DENSITY.
I'd be concerned that your tools are not installed correctly. The example project script should work with no errors.
It is no error, instead the placement is beautiful. Only it is too congested to be routed. I was looking for a method that can make this placement more sparse, to help routing.
If it's too congested to be routed, then isn't that an error?
Whe you run make user_proj_example and then make user_project_wrapper, do you get a clean result?
No DRC no lvs
This screenshot is of a modified user_prog_example build. I am unable to route it in reasonable time. Consider this as one of the design to be hardened as in your multi project example.
So above when you say it's the default, that's not true?
Not trying to be snarky but you should try to be as clear as possible when asking for help. O
Sorry I meant default configuration script, config.tcl
yeah, no problem. But there are lots of issues that can be side products of a tool install gone wrong, and then it wastes everyone's time trying to work out what the issue is when it's that the tools are bad
so a default run with user_proj_example should always work otherwise there is something badly wrong
so back to your q
try decreasing
(default is 0.55)
Or increase
default is 4
Tried first option, it yields a tiny island of cells in a big ocean placement remains same.
Let's try cell_pad
Also, I've had success with @Hieu Bui’s suggestion of PL_BASIC_PLACEMENT
also, try decreasing FP_CORE_UTIL (only has effect if your die size is not absolute)
I would put a bunch of these into a configuration script and use run_designs to try all combos
then check the resulting spreadsheet to guide you
Apparently, turning off PL_BASIC_PLACEMENT was the best option, and there is good reason to do so. I will write in detail to help others on this forum but for now thanks a lot @Hieu Bui and @Matt Venn
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