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  1. Qt
  2. QTBUG-65116

Qt3D cpu usage is much worse in 5.10.0 with RenderPolicy OnDemand

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    Details

    • Type: Bug
    • Status: Closed
    • Priority: P1: Critical
    • Resolution: Done
    • Affects Version/s: 5.10.0
    • Fix Version/s: 5.9.5, 5.10.1
    • Component/s: Qt3D
    • Labels:
      None
    • Environment:
      OS X, AppleClang

      Description

      Moving from 5.9.3 to 5.10.0, I noticed that my CPU usage goes from around 25% when active or idle on 5.9.3, to 95% when active and 120% when idle on 5.10.0. I am running with OnDemand rendering. I do not see large changes when running Always.

      I have run some profiling in Instruments, 10 seconds of each qt version, and have attached the screenshots below where I see very different behavior. Even specifying OnDemand I see that in 5.10.0 it is often calling performDraw when it does not in 5.9.3. Perhaps the problem is linked to ignoring OnDemand?

      I notice similar CPU usage increases when running the examples with OnDemand rendering. When running with the simple-qml example my CPU usage goes up to 229% when idle.

        Attachments

        1. 5.9.3.png
          5.9.3.png
          191 kB
        2. 5.10.0.png
          5.10.0.png
          174 kB

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              Assignee:
              dragly Svenn-Arne Dragly
              Reporter:
              tconsumer tconsumer
              Votes:
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                Resolved:

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