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Critical Path in a design

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onta00

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Hi everyone
After the compilation, given that we are at the top level, using the report_timing we obtain a certain path with a certain time X. After changing the current design(going more inside) and using the report_timing command again, we obtain a path with a time that is HIGHER than X. Why? Shouldn't the report_timing command display the same path when we are in the top level design?
 

Hi everyone
After the compilation, given that we are at the top level, using the report_timing we obtain a certain path with a certain time X. After changing the current design(going more inside) and using the report_timing command again, we obtain a path with a time that is HIGHER than X. Why? Shouldn't the report_timing command display the same path when we are in the top level design?

are you sure you are not confusing the path timing with the slack? slack is supposed to be higher.
 

are you sure you are not confusing the path timing with the slack? slack is supposed to be higher.

The command report_timing reports timing paths. I've used the same command in the top level entity and in the inner entity
 

The command report_timing reports timing paths. I've used the same command in the top level entity and in the inner entity

It reports slacks. Make sure you are not reading it wrong. Care to post the paths here?
 
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    onta00

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At the top level the worst path will be any path in the top level. At "current_instance <hier>", the worst path will be only the worst path within that particular <hier>. Check that you have the exact same timing path reported in both cases.
 
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    onta00

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