What checks are needed when applying useful skew and how to apply limit?

o   Setting Limits: setUsefulSkewMode -maxAllowedDelay <Value>

o   Checks Needed When Applying Useful Skew: when usefulSkew is enabled in preCTS and at CTS, tool does all the checks before applying for the skew. At ECO if doing manual adjustment, below things to be checked:

o    Hold Time on the Same Path: The most critical check.

o    Timing to Launch Flop: Check setup and hold timing for paths ending at the launch flop. If skew is borrowed from this path, it may get setup violation.

o    Timing from Capture Flop: Check setup and hold timing for paths starting from the capture flop. If skew borrowed from this path, it may get setup vio.

o    Overall QOR: After applying useful skew (usually as part of an optimization run or ECO), re-run full STA to ensure no new violations have been created

o    CPPR Impact: Pushing Capture or pulling Launch flop to add skew, may change your CPPR and contribute to timing violations.