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Max tran violations

diablo

Pls suggest on improving max tran violations in SocEncounterafter after routing. After postCTS, there are no violations on setup, hold, max_tran, max_fanout. However, after post route, I can see around 100 of max_tran violations but there is still no setup and hold violations. After iteratively running  optDesign -postRoute -drv, i still get those violations. I was wondering why the tool is not using buffers to fix it. 

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  • The tool assumes that you are happy with the performance of your clock tree and that it is optimized for skew. If it were to try to change the clock tree, it will change the skews and possibly create new timing violations. If you want to repair transitions in the clock tree, you can try using the ckECO command. But fixing transitions in the clock tree may make skew worse.

    I usually let the clock tree violate transition constraints in favor of better skew results. Unless the clock tree transitions are outrageously slow (which they shouldn't be since CTS should not let them), I leave them alone.

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  • The tool assumes that you are happy with the performance of your clock tree and that it is optimized for skew. If it were to try to change the clock tree, it will change the skews and possibly create new timing violations. If you want to repair transitions in the clock tree, you can try using the ckECO command. But fixing transitions in the clock tree may make skew worse.

    I usually let the clock tree violate transition constraints in favor of better skew results. Unless the clock tree transitions are outrageously slow (which they shouldn't be since CTS should not let them), I leave them alone.

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