QWebkit: V4 is really slow compared to V8 for large sources
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My goal is to build a javascript framework rendered in a QWebView, not using Qml, just standard javascript.
My library is near 1Mb of pure compact javascript with a lot of great ui components.
I do that because my sources can be run locally (desktop mode) & remotely (cloud mode).On QT5.1 (with V8 engine), loading & running such library was 125ms (more than acceptable)
Now on QT5.2 (with V4 engine), loading & running is 1480ms… same result with QT5.3more than 10 times slower.
Do any body got an idea ?
Must I use the old QT5.1 to get acceptable performances ? -
Hi,
QWebView uses the JavaScript Engine in WebKit (JavaScriptCore), its not related to the JavaScript Engine used in QML
Take a look at WebKit for your performance issue...
Fyi: dit you try the new QtWebEngine?
http://blog.qt.digia.com/blog/2013/09/12/introducing-the-qt-webengine/ -
Hi eco747,
V4 is only used for the QML engine. Qt WebKit uses JSC (not V8 or V4).
But anyway, you might have found a regression. Please report the issue to https://bugreports.qt-project.org/ and include a small, compilable sample code that demonstrates the issue.
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Hi,
I tried Carousel QML demo (https://github.com/sgcc/qtquick_demo/tree/master/Qt5_NMap_CarouselDemo_1.0).
I can confirm than Qt5.2.1 slower than Qt5.1
Qt 5.1 gives 56FPS on my hardware.
Qt 5.2.1 only gives 45FPS.The only difference is Qt version, the rest is the same.
I really think that V4 is much slower to V8.