Compilation differences between Quartus Prime and Design Space Explorer

[TuckerZ]

Hello, 

I am using Quartus Prime Standard Edition version 21.1 and there is an observed issue with the compilation in Design Space Explorer and Quartus prime. I used Design space explorer to search for seeds to help close timing. The results of which did list that timing was met with certain searched seeds. I used one of those seeds in Quartus prime and the compilation has timing violations. There is a mismatch in the timing results of the compilations of the two programs.  

There was a topic about this already, but for Quartus II and a much earlier version. Plus, the error was not explained or solved. I'm not exactly sure what's happening now. Can anyone confirm this is a known issue? Is this common user error? 

Thank you, 

Tucker Zischka 

[SyafieqS]

Hi Tucker,

Seed sweep normally be used if you are having a small margin left to close. Same number of seed does not guarantee the timing as this might be due to different environment. Running compilation in Quartus and DSE obviously two different way and this behavior is expected.

[TuckerZ]

How do I align them? 

[SyafieqS]

You cant align them as this is expected result.

What you can do is choose the seed of closed timing result and doing analysis on that.

Also, how big is the margin between running on Quartus and DSE?

[TuckerZ · Accepted solution]

The margin is a couple hundred pico-seconds. If you can't align them, what is the point of using Design Space Explorer? It becomes a difficult tool to use.

However, I solved my own problem: I was able to align the two. The number of processors specified has to be the same in both environments for the results to be the same. Once those were changed to be the same, Design Space Explorer produced the same compilation results as Quartus.