How to get the area breakdown of plugins in Vexii?

[Jzjerry]

Hi,

I'm trying to check the area breakdown of the plugins in Vexii (like the area of IntAlu, Lsu or Branch).
Is there a way to generate plugins as separate verilog modules? Or are there any other ways to analyze their area?

[Dolu1990]

Hi,

I would say, the only way is to run the synthesis flow between a configuration with and without a feature to get its "real" ressource usage. It may not be faisable for everything thing as there may be some coupling between a few plugins.
Using verilog module to contains logic feature get messed up a lot with hierarchy flattening.

[Jzjerry]

Just made some data analysis on the impact of generation options on the area (LUTs+FFs):

Basically, I generated 1024 Vexii designs with random configurations and ran a Vivado script to synthesize them, then got the area report. For boolean options (like with-late-alu), the blue points are those that set the option to true, and the red ones are false. For integer options (like xlen and lanes), the red points are with higher values.

Could be a reference for those who want to resize their Vexii I hope 🤔.

[Dolu1990]

Nice :D
Thanks ^^
1024 designs, how long did that toke XD ?

[Jzjerry]

5 minutes per design, so around 4 days in total XD.
Can be faster if do it in parallel.