[webkit-qt] Performance regression

Sriram Neelakandan sriram.neelakandan at gmail.com
Wed Mar 21 22:03:18 PDT 2012

Hi Adam,

Not sure if this helps....

I used QtWebkit2.2 + Qt4.8 on Linux and found severe drop in render
performance, when compared to Qt4.7(internal QtWebkit)

I am not sure if it was due to some texture mapper / rendering changes that
were being refactored soon after 4.8 release. Some time during this texture
mapper would work only for OpenGL cases but not Linux/DFB.; but later i
guess texture mapper became more generic to use 2D hardware blitter (DFB)
as well

So upgrading QtWebkit from webkit.org trunk with texture-mapper enabled by
default solved my issue (but still i had to enforce a translate3d(0) by
force on the body)

On Thu, Mar 22, 2012 at 10:16 AM, Coda Highland <chighland at gmail.com> wrote:

> I'm on Mac (Snow Leopard), and building 32-bit (Carbon, of course) because
> of other dependencies.
> Back in Qt 4.7 (specifically, on August 14th, 2011), I had built the
> QtWebKit 2.2 branch from trunk in order to get some features I needed for
> my application.
> Today I got tired of dealing with the broken inspector and decided to
> update to 4.8.0. Unfortunately, the version of QtWebKit bundled with 4.8.0,
> as well as a fresh checkout of trunk, have severe performance regressions,
> especially with scrolling. I kept Qt 4.8.0 but switched back to my old
> build of QtWebKit from August 14th and the performance returned to normal.
> (I still had another regression regarding opacity, but that seems to be a
> Carbon-specific regression in Qt itself, not QtWebKit.)
> I'm not looking forward to spending my weekend bisecting this; is this a
> known issue? Does anyone have any pointers on what change(s) might be
> relevant?
> Thanks,
> /s/ Adam
> _______________________________________________
> webkit-qt mailing list
> webkit-qt at lists.webkit.org
> http://lists.webkit.org/mailman/listinfo.cgi/webkit-qt

Sriram Neelakandan
Author - Embedded Linux System Design And Development (
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