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ZaidSahawneh's avatar
ZaidSahawneh
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1 month ago

Quartus Prime Pro Hierarchy View has blank rows for some instances

Hello,

I am using Quartus Prime Pro and after a compilation of my design, the Hierarchy view in the Project Navigator shows the board utilization metrics such as ALMs needed, DSP blocks, etc.

I have noticed that some lines appear completely blank. I didn't initially believe these are due to components being synthesized out because these components that appear blank appear in the RTL viewer and my understanding was that the RTL Viewer wouldn't show the component if it was synthesized out. I am looking to confirm why some instances appear as blank items in the Hierarchy view. Is the tool taking advantage of resource sharing and therefore no new resources are used for that instance? Does the tool refrain from repeating data so that's why I have 1 instance with data and 2 others that are the same component without data? Is a blank cell and a 0 the same thing expressed differently depending on if the row as a whole was 0s? Is this just due to the tool not wanting to repeat itself because I've noticed I can get utilization metrics for instance_0 of a component but instance_1 and _2 of the same component are blank. Any subcomponents of a blank instance are also always blank as well.

Normally there aren't many blank lines and the components were small enough for me to assume it was resource sharing, but with my current design, the components that are blank are seemingly pretty large and complicated so I'd like to learn more about how the tool is reporting and I haven't found an answer in your published documentation yet. 

Compilation

9 Replies

  • ShengN_altera's avatar
    ShengN_altera
    Icon for Super Contributor rankSuper Contributor
    1 month ago

    Could you screenshot the Hierarchy? Probably that particular instance don't use ALM.

    • ZaidSahawneh's avatar
      ZaidSahawneh
      Icon for New Contributor rankNew Contributor
      1 month ago

      Unfortunately I cannot share a screenshot but I can make an example below of what I see

      Instance           | Entity     | ALMs needed  | ALMs used       | ...
      ---------------------------------------------------------------------------------------------------------
      top                    |                |  564213            |  564210            |
         inst_0             |  e_0       |    23153            |    23153            |
         inst_1              |  e_1        |    23154            |    23151             |
            inst_1_0      |  e_4       |       2135            |     2135             |
            inst_1_1       |  e_5       |     21019            |    21019             |
         inst_2             |  e_2       |                           |                           |
            inst_2_0      | e_6        |                           |                           |
            inst_2_1      |  e_7        |                           |                           |
         inst_3             |  e_3       |   517709            |   517709            |
         inst_3.2          |  e_3       |                           |                           |

      note that as I mentioned, 
      some instances have no data to the left (completely blank)
      if one of those instances have subcomponents, those are blank as well
      and some instances share an entity and sometimes one instance of that entity has metrics while the others do not (not every time)

      Theses instances with blank lines are all in RTL viewer so I do not believe they are being synthesized away. I'm just looking to confirm that this may be due to something like resource sharing and is an accurate representation of board utilization before I report the metrics forward.

      • sstrell's avatar
        sstrell
        Icon for Super Contributor rankSuper Contributor
        1 month ago

        Assuming you've run full compilation, what you see in RTL Viewer is not an accurate representation of the final place and route.  That instance could have been optimized away by the Fitter.  Use one of the Technology Map Viewers instead of the RTL Viewer to see if the instance is still there after fitting.

  • ZaidSahawneh's avatar
    ZaidSahawneh
    Icon for New Contributor rankNew Contributor
    1 month ago

    Just wanting to clarify by the row being completely blank, I mean the utilization metrics being blank cells but the Instance and Entity columns are filled with the correct name information. Apologies for being un-specific at first.