Greetings Q1 Is it possible to report the shortest setup pat

Question

Greetings Q1 Is it possible to report the shortest setup path in OpenSTA not to be confused with hold time check I m thinking of moving from my own hobby level STA engine to the way more professional OpenSTA tool but I need at least the shortest setup path Do I miss something in the OpenSTA docs Q2 Is it possible to display a timing histogram in OpenSTA Thanks a lot in advance

Vijayan Krishnan · Answer

Vijayan Krishnan · Answer

Using OpenROAD GUI you can trace the timing path as contain built in OpenSTA timing engine

Tobias Strauch · Answer

< Vijayan Krishnan> Thank you as always I was aware of the documentation where I couldn t find an answer to my questions Q1 Is it possible to report the shortest setup path in OpenSTA It seems as if the OR GUI does not add features to answer this one Q2 Is it possible to display a timing histogram in OpenSTA

Matt Liberty · Answer

1 Do you mean in terms of levels or delay How would you use it 2 Not yet but see <https github com The OpenROAD Project OpenROAD issues 2649>

Tobias Strauch · Answer

Thank you < Matt Liberty> Q1 In MPW 8 I have a wavepipelined RISC V using timing driven buffer insertion on the netlist to achieve a certain minimal length constraint per path I do STA on the layout as well shortest setup but I would love to do a multicorner backend STA with OpenSTA as well in particular showing the shortest setup path Q2 AAAAAAh Awesome Very nice Don t want to be too pedantic but I would argue that you NOT only need a single path per endpoint for the wall of slack I think OpenSTA might be limited don t get me wrong it s already fantastic in showing the complete slack distribution per endpoint and therefore the shortest setup path as well

Matt Liberty · Answer

You can trace as many paths per endpoint as you wish in osta Its mostly a matter of what you want to see

Matt Liberty · Answer

Shortest setup doesn t make much sense to me as setup is naturally a max delay property Why not use hold for this purpose

Tobias Strauch · Answer

Don t want to bother you but in my opinion The number of paths through a logic can be very very large So this kind of analysis can t be done with reporting It needs to be part of in the STA implementation philosophy to generate specific reports Hold time uses the same clock Setup the next or consecutive clock edges The results I m looking for are based on consecutive clock edges and FF setup checks If you are interested in wavepipelining you might want to check out <https www cs princeton edu courses archive fall01 cs597a wave pdf> Okay it s an old idea but still a lot of fun

Matt Liberty · Answer

I don t think any timer open or proprietary has this sort of check afaik

Tobias Strauch · Answer

Synopsys had it 20 23 years ago when I was fooling around with it

Tobias Strauch · Answer

For sure it still has