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  1. Qt
  2. QTBUG-136587

[Reg 6.5.2 -> 6.8.1] Significant increase in CPU load in QSGRenderThread

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    • Linux/Yocto

      See the attached sample project (it's not very minimal right now; I'll upload a stripped-down reproducer when I have time).

      • With Boot to Qt 6.5.2, my Raspberry Pi 4 runs at ~60% CPU load
      • With Boot to Qt 6.8.1/6.8.3, my Raspberry Pi 4 runs at ~80% CPU load

       

      Other observations

      • When using perf record -e cycles -p $(pidof QQuickTableViewSampleApp) sleep 30 Qt 6.8 seems to record ~20k more CPU events than Qt 6.5.2 in the same 30-second window.
      • The CPU load is negligible on my Windows 10 22H2 PC (i7-770 CPU)

        1. perf-qt6.5.2.png
          79 kB
          Sze Howe Koh
        2. perf-qt6.8.1.png
          77 kB
          Sze Howe Koh
        3. perf-qt6.8.3.png
          77 kB
          Sze Howe Koh
        4. perf-qt6.8.3-depatched.png
          86 kB
          Sze Howe Koh
        5. QQuickTableViewSampleApp_v2.zip
          19 kB
          Andy Nichols
        6. QQuickTableViewSampleApp.zip
          12 kB
          Sze Howe Koh
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            richard Richard Moe Gustavsen
            skoh-qt Sze Howe Koh
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              Created:
              Updated:
              Resolved:

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