Intel® Quartus® Prime Standard Edition User Guide: Design Compilation

ID 683283
Date 9/24/2018
Document Table of Contents

1.4.2. Optimizing a Timing-Critical Partition

Scenario background: You have just performed a lengthy full compilation of a design that consists of multiple partitions. The Timing Analyzer reports that the clock timing requirement is not met, and you have to optimize one particular partition. You want to try optimization techniques such as raising the Placement Effort Multiplier and running Design Space Explorer II. Because these techniques all involve significant compilation time, you should apply them to only the partition in question.

Use the flow in this example to optimize the results of one partition when the other partitions in the design have already met their requirements. You can use this flow iteratively to lock down the performance of one partition, and then move on to optimization of another partition.

Perform the following steps to preserve the results for partitions that meet their timing requirements, and to recompile a timing-critical partition with new optimization settings:

  1. Open the Design Partitions window.
  2. For the partition in question, set the netlist type to Source File.
    • If you change a setting that affects only the Fitter, you can save additional compilation time by setting the netlist type to Post-Synthesis to reuse the synthesis results and refit the partition.
  3. For the remaining partitions (including the top-level entity), set the netlist type to Post-Fit.
    • You can optionally set the Fitter Preservation Level on the Advanced tab in the Design Partitions Properties dialog box to Placement to allow for the most flexibility during routing.
  4. Apply the desired optimization settings.
  5. Click Start Compilation to perform incremental compilation on the design with the new settings. During this compilation, the Partition Merge stage automatically merges the critical partition’s new synthesis netlist with the post-fit netlists of the remaining partitions. The Fitter then refits only the required partition. Because the effort is reduced as compared to the initial full compilation, the compilation time is also reduced.
To use Design Space Explorer II, perform the following steps:
  1. Repeat steps 1–3 of the previous procedure.
  2. Save the project and run Design Space Explorer II.