I m running report checks on `sta` and I m co

Question

< U018LA3KZCJ> I m running report checks on `sta` and I m confuse about this results It seems I m not getting all the violations results I thought I would get in the first case but if I specify a ` through` parameter like in the second case I get some extra results ```report checks path delay min format summary group count 1000000 slack max 0 Startpoint Endpoint Slack mprj wrapped quad pwm fet drivers 5 3974 Q sky130 fd sc hd dfxtp 1 soc core 34944 D sky130 fd sc hd dfxtp 1 1 09 mprj wrapped quad pwm fet drivers 5 3962 Q sky130 fd sc hd dfxtp 2 soc core 34942 D sky130 fd sc hd dfxtp 2 0 96 mprj wrapped quad pwm fet drivers 5 3950 Q sky130 fd sc hd dfxtp 1 soc core 34940 D sky130 fd sc hd dfxtp 1 0 90 report checks path delay min format summary group count 1000000 slack max 0 through mprj wrapper fibonacci 3 Startpoint Endpoint Slack mprj wrapper fibonacci 3 3283 Q sky130 fd sc hd dfxtp 2 soc core 34942 D sky130 fd sc hd dfxtp 2 1 25 mprj wrapper fibonacci 3 3282 Q sky130 fd sc hd dfxtp 1 soc core 34944 D sky130 fd sc hd dfxtp 1 1 21 mprj wrapper fibonacci 3 3284 Q sky130 fd sc hd dfxtp 1 soc core 34940 D sky130 fd sc hd dfxtp 1 1 21``` Is there something I might by missing about how report checks works

Maximo Balestrini · Answer

I m using `sta` from `efabless openlane mpw 3a` docker

Matt Liberty · Answer

< U01AX8X5N58> would you comment on this sta concern

Dinesh A · Answer

< U01HBEED5T8> Did you got any info on why ` through` showing additional result

Maximo Balestrini · Answer

Not yet

Matt Liberty · Answer

I suggest you open an issue with a testcase

Maximo Balestrini · Answer

< U018LA3KZCJ> Ok I wanted to be sure that there wasn t something I wasn t getting about how that functions works I ll create and issue with the test case

Maximo Balestrini · Answer

I looked a little bit more into this issue One important thing I noticed is that the SPEF for that macro wrapper fibonacci 3 didn t exactly match the verilog version So that s something that can definitely cause issues I guess The other thing I realized is that the endpoint for those paths is the same so I think that might cause the report to show only one of them It should be the worst slack and doesn t look like it from those results but when I checked it was for some reason when I used the ` through` parameter the report didn t remove the `clock reconvergence pessimism` making the slack worst So now I m digging a little bit about that clock reconvergence pessimism issue to see if I understand why that might happen

Tom Spyrou · Answer

< U01HBEED5T8> I would need to see the full timing report especially the header showing the path group and the end showing the slack In the case of through is the path specified is unconstrained while the default path is constrained there could be a difference

Maximo Balestrini · Answer

< U01AX8X5N58> it seems that if I use the path of the macro ej `mprj wrapper fibonacci 3` in ` through` the report doesn t calculate the CRP but if don t use the param or if I set it to one of the leaf cells of the macro `mprj wrapper fibonacci 3 2746 ` it does Is that ok Note this sta script loads a hierarchical design caravel + user project with many verilog files and `read spef path` to assign spef files to their instances

Tom Spyrou · Answer

If you look at the source flop and destination flop clock paths do you see a common root If yes there should be crpr if no there should not be It is easy to see in the full clock expanded report

Maximo Balestrini · Answer

In those reports I attached the paths are exactly the same in the 3 cases but depending on how I called report checks the crpr is 0 or 0 69 which seems the correct value

Tom Spyrou · Answer

That looks like a bug then If you can file an issue it would be great If the path and the transitions are identical the crpr should be identical

Maximo Balestrini · Answer

< U01AX8X5N58> filed the issue with a test case Creating the test case I discover that running ` through somemacro` the first time calculates the cprp but if I then call ` through somemacro child cell on path` and then I call ` though somemacro` again this time the cprp is 0

Maximo Balestrini · Answer

< U01AX8X5N58> I have another doubt about report checks through parameter and these hierarchical designs Should the call with through `mprj wrapped hack soc dffram 9` include the results from the call with through `mprj wrapped hack soc dffram 9 soc spi video ram 1 write fifo dffrf` Here `wrapped hack soc dffram 9` and `dffrf` are defined in separate verilogs and have their own spef files

Tom Spyrou · Answer

Normally sta users specify a through pin versus a through instance If you get the same path with different crpr and you see the same common clock root in the expanded clock somethings is wrong