[webkit-qt] Qtwebkit 5.212 setuserstylesheet() is taking 7seconds time first time on startup

[Ramakanth Kesireddy]

Yes delay is nothing but the execution time of setuserstylesheet with
7seconds.

If I comment the entire stylesheet, it still takes 7 secs for any webpage.

Is it recommended to use static QWebSettings::global settings() instead of
dynamic instance with webview->page()->settings()?

Best Regards,
Ramakanth

On Fri, 4 Dec, 2020, 23:36 Konstantin Tokarev, <annulen at yandex.ru> wrote:

>
>
> 04.12.2020, 10:36, "Ramakanth Kesireddy" <rama.kesi at gmail.com>:
> > Hello Konstantin,
> >
> > Thanks for the details.
> >
> > Also the same UiApp setuserstylesheet codes work for Qt 4.8 based
> QtWebKit 2.3.4 without any delay first time.
> > Do you think of any potential changes in QtWebkit 5.212 Alpha4 that
> could cause the first time load issue of user stylesheet?
>
> First, is "delay" you are talking about equal to execution time of
> setUserStyleSheet? You can measure it simply by putting QElapsedTimer
> before call and printing its value afterwards.
>
> My first guess about this "delay" is that it is caused by complex layout
> computation. However it's hard to guess why 4.8 behavior is different
> without profiling.
> Did you try to do any profiling of what happens inside setUserStyleSheet?
> Does execution time of setUserStyleSheet depend on page or stylesheet you
> are trying to load?
>
> >
> > Best Regards,
> > Ramakanth
> >
> > On Thu, Dec 3, 2020 at 10:26 PM Konstantin Tokarev <annulen at yandex.ru>
> wrote:
> >> 03.12.2020, 19:40, "Ramakanth Kesireddy" <rama.kesi at gmail.com>:
> >>> Ok Thanks for your mail.Shall check and update further.
> >>> Is it by design QWebSettings is not thread safe or any means to make
> thread safe?
> >>
> >> WebCore by design is not thread safe. QWebView and all other classes
> from QtWebKitWidgets module use WebCore directly and so aren't thread safe
> too. You must call them from the same thread QWebView was created (and it
> should better be main GUI thread, i.e. where QApplication is created).
> >>
> >> For comparison, QML API uses multi-process architecture so WebCore is
> used in a background process and minimizes blocking of GUI process (i.e.
> your application). Though that API is still not thread safe respective to
> threads in GUI process (though it might be reentrant).
> >>
> >> --
> >> Regards,
> >> Konstantin
>
>
> --
> Regards,
> Konstantin
>
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