What do MET and VIOLATED mean in a PrimeTime constraint report?

Short Answer

MET and VIOLATED are the pass/fail labels report_constraint (PT) prints next to every checked endpoint. MET means the slack at that endpoint is zero or positive — the check passed with no margin problem. VIOLATED means the slack is negative, so the endpoint is failing that check and needs a fix or a legitimate exception.

Technical Explanation

These two words are how a summary report tells you where to look, before you ever see a number.

• Each line in a report_constraint (PT) listing names an endpoint, a check type — setup, hold, max_transition, and so on — a slack value, and the status word MET or VIOLATED.
• VIOLATED simply means slack is less than zero for that check; the exact magnitude still has to be read from the slack column next to it.
• MET does not mean the path has huge margin — an endpoint can be MET at +2ps, which is technically passing but has almost no room left.
• The status word is computed the same way for every check type, so a VIOLATED max_transition line and a VIOLATED setup line use the same rule: slack below zero.
• Scanning for the word VIOLATED with report_constraint -all_violators (PT) filters the report down to only the failing lines, which is faster than reading every MET line too.
• A design can show all MET and still not be signoff-clean, because report_constraint only reports on the checks it was asked to run — an unconstrained endpoint never gets a line at all.

Follow-up Question & Model Response

If report_constraint prints no line at all for a particular endpoint, does that mean it is safely MET?

Candidate Model Response: No. report_constraint only reports on endpoints that have a check to evaluate — an endpoint missing an set_input_delay or set_output_delay (SDC) constraint has no path to check and produces no line at all, not a MET line. That is a different, more serious problem than VIOLATED, because the tool never looked at that endpoint's timing. This is exactly what check_timing (PT) is built to catch separately, by listing every endpoint that is missing a constraint rather than showing it as passing. A designer who only reads report_constraint for MET/VIOLATED can miss an unconstrained endpoint completely.