markdown/gh_discussions/Documentation/4495.md

# pad_left/right units for GPL and repair_clock_inverters description

Tool: Global Placement

Subcategory: Missing information

## Conversation

### 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)](https://github.com/The-OpenROAD-Project/OpenROAD/tree/master/src/gpl) and the use/behavior of `repair_clock_inverters` [(RSZ).](https://github.com/The-OpenROAD-Project/OpenROAD/blob/master/src/rsz/README.md) 



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.

### 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