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NVC performance with Vunit #1036

@Blebowski

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@Blebowski

Hi,

I am trying to port my project:
https://github.com/Blebowski/CTU-CAN-FD

that I run with VUnit from GHDL into NVC. I managed to get everything working, and I can run the regression
with the same results in GHDL and in NVC.

The issue I face, is that NVC run-time is almost double the GHDL run-time (when executed via VUnit, I have
not tried to profile "raw" commands typed into the command line).

The analysis time of NVC is much smaller, but since analysis takes fraction of the overal regression, in total
run-time GHDL wins.

I would be curious to find out why does this occur. AFAICT, NVC is faster simulator.

My design contains large constant arrays of large structs that presumably take long time to elaborate.
When I run single test with -v, I see that VUnit always elaborates the design with NVC. Therefore,
each test requires separate elaboration since NVC does not support run-time setting of generics.

Does VUnit elaborate each test in GHDL too ? Or does Vunit in some smart manner passes the generics
such as test name, seed or other numeric parameters only to GHDL simulation ?

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