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  1. Qt
  2. QTBUG-86354

A huge performance regression of QTextBrowser::setSource()

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Details

    • Bug
    • Resolution: Done
    • P1: Critical
    • None
    • 6.0
    • GUI: Text handling
    • None
    • 313ed3d19ad41c2819265b4667bb7f28a024dd89 (qt/qtbase/dev) 1b06c07115d7da4fb2af05d30647d822c3ccae7a (qt/qtbase/dev)

    Description

      This is visible in Assistant. Comparing the time spent inside setSource (qt 5) and doSetSource (qt 6) it's about 25 times longer.

      To reproduce:
      Run assistant, go to index tab, type "map" and select the one coming from QtConcurrent Namespace. I've measured the time spent inside a call to QTextBrowser::setSource(resolvedUrl); from void HelpViewer::setSource. In Qt5 it's ~240 ms, while in Qt6 it's ~6800 ms (yeah, nearly 7 seconds).

      Attachments

        1. qt5textbrowser.png
          570 kB
          Eskil Abrahamsen Blomfeldt
        2. qt6textbrowser.png
          557 kB
          Eskil Abrahamsen Blomfeldt
        3. qtbug86354_textbrowser.zip
          12 kB
          Eskil Abrahamsen Blomfeldt
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          People

            laknoll Lars Knoll
            jkobus Jarek Kobus
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            Dates

              Created:
              Updated:
              Resolved:

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