Hmm... in various points throughout my build I've gotten the following warnings at the end: • There are max slew violations in the design at the typical corner • There are max capacitance violations in the design at the typical corner • There are max fanout violations in the design at the typical corner What would be a good way to address each of these issues? More specifically, what knobs should I be adjusting in the configuration file for each warning?

check constraints for fanout numbers. Warning can be ignored

Is that just ``SYNTH_MAX_FANOUT` and

CLOCK_BUFFER_FANOUT

?`

check

base.sdc

It looks like it uses

SYNTH_MAX_FANOUT

for fanout selection. I'd imagine that I'd have to lower that in order to remedy the "max fanout violations" error, yes?

just comment that line will clear the warning

I see the default is

10

, but a lot of designs seem to lower that to `6 or

8

.`

yes.

What are the implications of ignoring that warning? Will a high fanout cause production issues?

production issue consider ERROR message. Warning won't be problem

Fwiw I don't think max fanout should be used after synthesis is over. At that point max cap/trans is more useful.

@Sean Cross I recently got some info from @mshalan, one of the leads on openlane

Wow, that's a very nice document. Covers a lot of questions I had. Frequently.

@Matt Venn I think capacitance and slew margins are percentages. Setup and hold margins are ns (or whatever the liberty unit of timing is)

Yeah, I'm a bit confused, I put in verbatim what @mshalan told me