Step 5: Accumulating Suggestions - 2020.2 English

1. Click on GENERATED. RQS_CLOCK-15 is a message that reports the high THS paths but does not provide an automatic suggestion. Therefore, we will focus on RQS_CLOCK-1-1. This suggestion applies CLOCK_DELAY_GROUP to related clocks.
2. Click on RQS_CLOCK-1-1 to view the detailed report. In this report, you can see that there is a high clock skew.

   Clock skew is difficult to identify before place_design as the skew estimate depends heavily on placement. As a consequence, RQS does not offer this suggestion unless a design is placed. Whenever there is a change in information level, it can be worth running report_qor_suggestions. The following summarizes the changes as you progress through the tool flow:

   • Clocking estimates are accurate after place_design
   • Congestion is available after placement and improves further after routing
   • Timing estimates improve throughout the flow and are impacted by the number of paths analyzed
3. Click Export Suggestions. When suggestions are exported, the APPLIED status is reset. All the previous suggestions and the new RQS_CLOCK-1-1 are combined into one file. You can overwrite the previous file and reuse the runs, or create a new file and runs.
4. Select the file location to overwrite the existing file. You can find out the location of this by selecting it in the sources window. Alternatively, it should be at the following location if you have followed the steps carefully <extract_dir>/Lab2/project_2/project_2.srcs/utils_1/imports/project_2.

You are now at the point where you know the fundamentals in handling RQS files and accumulating suggestions. If you have time, rerun implementation through to route_design and examine the impact of the latest suggestion. Alternatively generate alternative suggestions by running report_qor_suggestions on your own design.