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dj-park's avatar
dj-park
Icon for Occasional Contributor rankOccasional Contributor
3 years ago
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Question on AN899 (Reducing Compile Time with Fast Preservation)

My understanding is that Fast Preservation option is for when you want to import the "static" design, but the tool unnecessarily spends time with compiling the static design. 1) In this page of ...
  • sstrell's avatar
    sstrell
    3 years ago

    Like I said, if you're not specifically creating a PR design, then you would want to use the Reserved Core option just like the tutorial says. Setting it to Reconfigurable enables additional device features and logic to allow for a runtime partial reconfiguration, which is not necessary. Fast Preservation can be used for either a PR or non-PR design. This training sums it all up pretty well: https://cdrdv2.intel.com/v1/dl/getContent/652891

sstrell's avatar
sstrell
Icon for Super Contributor rankSuper Contributor
3 years ago

1) The Reserved Core option is used in this flow if you are not creating a PR design. If this was a true PR design, you would set it to Reconfigurable. Fast Preservation is not on by default because it should only be on for the additional implementation revision, not the base revision.

2) That's still more than a 50% compile time reduction on a Stratix 10 compilation which can take many hours for a large design. The tool still has to analyze the entire design. It of course depends on how much of the design you are preserving. The more % of your design in the static region, the greater the savings.