pad_left/right units for GPL and repair_clock_inverters description

[lustefan97]

I looked in OpenROAD documentation for Global Placement and Gate Resizer to get more detail about the units of the pad_left/right parameters of the global_placement command (GPL) and the use/behavior of repair_clock_inverters (RSZ).

Both the variables units description is missing (while present for DPL (site count units), but since the two tools are different I don't want to assume it is the same for both) in GPL, and there is no description concerning repair_clock_inverters use case or behavior description (like there would be for repair_timing or repair_design.

What are the units of pad_left/right, and what does repair_clock_inverters do/how to use it ?

[maliberty]

The units are sites from the LEF.

repair_clock_inverters is useful when you have an inverter in the clock tree that would split the tree. It clones the inverter so you have one per flop instead.

[lustefan97]

When should repair_clock_inverters be used in a script ? After creation of the CT and after repair_clock_nets ? Or it could be used before CTS with little to no repercussion ?

[maliberty]

before CTS see https://github.com/The-OpenROAD-Project/OpenROAD-flow-scripts/blob/181e9133776117ea1b9f74dbacbfdaadff8c331b/flow/scripts/cts.tcl#L7

You might benefit from investigating how ORFS works

[lustefan97]

@maliberty Adding a description to the command documentation in the user guide could also help... I already used it before clock CTS without knowing why but look into the Gate Resizer to know why it is so, I couldn't find anything in the "Read the Docs"

[maliberty]

#4499