[Qt-qml] QML memory usage with "import QtWebKit"

[Gregory Schlomoff]

Hello Warwick

I just want to clarify something that maybe wasn't clear from my original
mail:

I'm sharing those numbers not because I think they are somehow too high, or
too low, but because I am surprised to see memory usage *grow by a
significant amount* even when I'm *not instantiating* anything.

Put it another way: the fact that a single "import WebKit 1.0" line adds 10
MB of memory usage, even though I'm NOT instantiating any WebView element is
an unexpected behaviour to me, and may indicate either a bug with the way
QML deals with imports, or a normal but unexpected behavior that should be
explained / documented.

Thanks

Greg

On Wed, Dec 15, 2010 at 8:51 AM, <warwick.allison at nokia.com> wrote:

>  “Memory usage” is not a simple integer. If those numbers are mainly
> shared read-only code pages it’s perfectly normal and you may shrug and move
> on, if they’re  for every application using webkit that would be unexpected.
>
>
>
> But in general, don’t expect a web runtime to somehow be small just because
> it happens to be instantiated from QML. Doing HTML from QML is no better an
> idea than doing it all in a regular web browser.
>
>
>
> --
>
> Warwick
>
>
>
> *From:* qt-qml-bounces at trolltech.com [mailto:qt-qml-bounces at trolltech.com]
> *On Behalf Of *ext Gregory Schlomoff
> *Sent:* Tuesday, December 14, 2010 4:52 PM
> *To:* Brasser Michael (Nokia-MS-Qt/Brisbane)
> *Cc:* qt-qml at trolltech.com
> *Subject:* Re: [Qt-qml] QML memory usage with "import QtWebKit"
>
>
>
> Hi Michael,
>
>
>
> Sorry, I didn't understand from your email if you think it's normal that
> memory usage goes up 10 Mb by just importing WebKit without using it ?
>
>
>
> What I mean is: does it look like an issue that should be investigated, or
> should we just shrug and move on?
>
>
>
> :)
>
>
>
> Thanks
>
>
>
> Greg
>
> On Tue, Dec 14, 2010 at 12:52 PM, <michael.brasser at nokia.com> wrote:
>
> Hi Greg,
>
>
>
> On 10/12/2010, at 4:52 PM, ext Gregory Schlomoff wrote:
>
>
>
>  Hi Michael,
>
>
>
> Somme additional figures:
>
>
>
> 1. Empty Rectangle, not importing QtWebkit: ~ 3MB
>
> 2. Empty Rectangle, importing QtWebkit: ~ 13MB
>
> 3. Rectangle with an empty WebView: ~ 14 MB
>
> 4. Setting url: "about:blank" in the WebView: ~15 MB
>
> 5. Setting url: "http://www.google.com/": ~19 MB (and a repaint bug:
> webview displays a checkered background, and I have to resize the window a
> little bit to make it actually paint the page.)
>
>
>
> Okay, thanks for sharing these. They are in the ballpark of what I would
> have expected based on prior observation, though I am definitely not a
> webkit expert. If you want to dig more, you could try comparing with
> QWebView or QGraphicsWebView (QML WebView memory usage should be identical
> to QGraphicsWebView with QWebSettings::TiledBackingStoreEnabled set (which
> does increase memory usage because of the pixmap caching)). Maybe someone
> familiar with QtWebKit can provide more information, or say whether there
> are any ways to tweak the memory usage?
>
>
>
> You can track the repaint bug (I think they are the same) at
> https://bugs.webkit.org/show_bug.cgi?id=50222.
>
>
>
> Regards,
>
> Michael
>
>
>
>  All tests on windows 7 64-bits, running qmlviewer.exe built from the
> 4.7.0 branch on Oct, 6.
>
>
>
> Thanks,
>
>
>
> Greg
>
>
>
> On Fri, Dec 10, 2010 at 12:12 PM, <michael.brasser at nokia.com> wrote:
>
> Hi Greg,
>
> >From what I remember 10MB for the "base" usage of webkit sounds about
> right, though I didn't realize that just an import statement would add this
> cost. Did you try any other configurations? e.g. did adding an empty WebView
> cause the memory to go up or was it still around 13MB?
>
> Regards,
> Michael
>
>
> On 30/11/2010, at 6:48 PM, ext Gregory Schlomoff wrote:
>
> > Hello,
> >
> > One simple observation. Launching the following code in qmlviewer.exe,
> > I get a memory usage of aroung 3 megabytes:
> > -----------------------
> > import QtQuick 1.0
> >
> > Rectangle {
> >       width: 200
> >       height: 200
> > }
> > ------------------------
> >
> > Now, with the following code, memory usage jumps to 13 megabytes. I'm
> > not instantiating any WebView element, just importing QtWebkit.
> > -----------------------
> > import QtQuick 1.0
> > import QtWebKit 1.0
> >
> > Rectangle {
> >       width: 200
> >       height: 200
> > }
> > ------------------------
> >
> > Is that normal? Would someone care to explain what the import
> > statement is doing that is adding 10 mb of memory consumption?
> >
> > Thanks
> >
> > Greg
>
> > _______________________________________________
> > Qt-qml mailing list
> > Qt-qml at trolltech.com
> > http://lists.trolltech.com/mailman/listinfo/qt-qml
>
>
>
>
>
>
>
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