is there an explanation somewhere of `PL_RESIZER_S...
# timing-closurea
Anish
10/28/2021, 6:21 PMis there an explanation somewhere of
PL_RESIZER_SETUP_SLACK_MARGINPL_RESIZER_HOLD_SLACK_MARGINj
jeffdi
10/29/2021, 9:30 PM
@User @User can you please respond to this?
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Vijayan Krishnan
10/30/2021, 7:52 AM@User default values found here OPENLANE_ROOT/configuration/placement.tcl
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Matt Venn
11/02/2021, 4:26 PMyes please can we get some help here
Matt Venn
11/02/2021, 4:26 PMI opened a comment on the google doc to ask what the values did and which way to change them to get improvements
Matt Venn
11/02/2021, 4:27 PM@User closed the comment saying to look at the docs: https://github.com/The-OpenROAD-Project/OpenLane/blob/master/configuration/README.md
Matt Venn
11/02/2021, 4:27 PMbut there is not really any help there either
Matt Venn
11/02/2021, 4:30 PMmaybe @User or @User could comment?
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Matt Liberty
11/02/2021, 5:14 PMNormally the resizer stops when it reaches zero slack. You can use those variables to tell it to "overfix". That can be useful as the repair is done before we have full routing details and it is possible it might not be conservative enough to account for final parasitics/timing.
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Matt Venn
11/02/2021, 5:20 PMIs the range 0 to 1? What would a setting of 1 do?
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Matt Liberty
11/02/2021, 5:21 PMit is the slack you want to fix to (time units)
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Matt Venn
11/02/2021, 5:21 PMAh!
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Matt Liberty
11/02/2021, 5:22 PMroughly start with whatever your negative margin is at the end of the flow (maybe plus a bit)
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Matt Venn
11/02/2021, 5:26 PMAny upper limit?
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Matt Liberty
11/02/2021, 5:44 PMthe higher you set it the more buffering/sizing/power you will consume so you don't want to crank it up needlessly
Matt Liberty
11/02/2021, 5:44 PMthere is no hard limit though
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Matt Liberty
11/02/2021, 5:45 PMat some value it will become impossible to meet - you can only make the design so fast