# openlane

Ataberk Olgun

08/27/2021, 10:34 AM
Hi all, this is coming from someone who mostly worked on FPGA designs using Vivado. Is there a methodology for performing timing closure using OpenLANE? When I check the timing report generated by the tool (e.g., synthesis/27-opensta_spef.timing.rpt) I have a hard time understanding what the critical path is (attached is one violated path from the report). In contrast, with Vivado, most of the time I can see the registers & wires that lie on the critical path. How can I make sense out of what is written in the timing report? More specifically, how do the sky130* elements on the path relate to the Verilog design?


08/27/2021, 11:29 AM
It seems the challenge would be yosys is using those generic names…

Ataberk Olgun

08/27/2021, 1:16 PM
According to this SO answer Yosys apparently already tries its best to retain the original names of the signals. Do you know if there is a way to make Yosys somehow associate the generated (assuming they are) sky130 elements to their most relevant Verilog signals?

Matt Liberty

09/02/2021, 9:17 PM
When you use -flatten in yosys it destroys the names. When you don't use -flatten you get terrible area. It's an area that OpenRoad is looking into.
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