[webkit-qt] [Qt] Strong performance degradation with DirectFB since r122720

[Simon Hausmann]

On Friday, September 14, 2012 04:25:18 PM ext Zoltan Horvath wrote:
> Okay, then it seems reasonable to roll it out, so I'm going to revert it
> next week.

Further discussion with Jocelyn concluded that reverting is indeed the least-
effort way of fixing this regression.

Simon

> On Fri, 14 Sep 2012 16:12:00 +0200, <jocelyn.turcotte at nokia.com> wrote:
> > Forget my last comment, this seems to be directly related to the use of
> > QImage instead of QPixmaps.
> > 
> > The directfb platform plugin uses QBlitterPaintEngine which handles
> > drawPixmap in QDirectFbBlitter::drawPixmap rather than using straight
> > CPU raster for drawImage.
> > 
> > ________________________________________
> > From: webkit-qt-bounces at lists.webkit.org
> > [webkit-qt-bounces at lists.webkit.org] on behalf of Turcotte Jocelyn
> > (Nokia-MP/Oslo)
> > Sent: Friday, September 14, 2012 3:53 PM
> > To: zoltan at webkit.org; webkit-qt at lists.webkit.org
> > Subject: Re: [webkit-qt] [Qt] Strong performance degradation with
> > DirectFB since r122720
> > 
> > Ahh it's a canvas test, this might also be related to the deep-copy
> > protection that was removed in the patch, when a QPainter is beginning
> > on an existing image.
> > 
> > ________________________________________
> > From: webkit-qt-bounces at lists.webkit.org
> > [webkit-qt-bounces at lists.webkit.org] on behalf of Turcotte Jocelyn
> > (Nokia-MP/Oslo)
> > Sent: Friday, September 14, 2012 3:35 PM
> > To: zoltan at webkit.org; webkit-qt at lists.webkit.org
> > Subject: Re: [webkit-qt] [Qt] Strong performance degradation with
> > DirectFB since r122720
> > 
> > Why was it necessary to switch from QPixmap to QImage?
> > 
> > I don't think that this can be solved on the Qt side, it's a design
> > advantage that QPixmap has in this kind of situations.
> > As far as I know this might be mostly related to reusing a graphics
> > buffer that already has been uploaded to graphics memory.
> > 
> > Jocelyn
> > 
> > ________________________________________
> > From: webkit-qt-bounces at lists.webkit.org
> > [webkit-qt-bounces at lists.webkit.org] on behalf of ext Zoltan Horvath
> > [zoltan at webkit.org]
> > Sent: Friday, September 14, 2012 3:17 PM
> > To: webkit-qt at lists.webkit.org
> > Subject: Re: [webkit-qt] [Qt] Strong performance degradation with
> > DirectFB since r122720
> > 
> > Hi there,
> > 
> > Shouldn't we report this on Qt-side instead?
> > 
> > Cheers,
> > Zoltan
> > 
> > 
> > On Fri, 14 Sep 2012 15:02:13 +0200, Allan Sandfeld Jensen
> > 
> > <kde at carewolf.com> wrote:
> >> On Friday 14 September 2012, Brianceau, Julien wrote:
> >>> With r126284 based webkit version, I get 11,3 displayed fps, with a CPU
> >>> usage of more than 95% With r126284 based webkit version with changeset
> >>> 122720 reverted, I get 25,6 displayed fps, with a CPU usage of about
> >>> 90%
> >> 
> >> Yes with a 50% speed regression also on Qt5, I think we need to revert
> >> the
> >> patch in trunk, otherwise I would have suggested only reverting it in
> >> QtWebKit
> >> 2.3. But having as few difference as possible is better, so I am
> >> actually
> >> relieved it was also slower in Qt5.
> >> 
> >> Cheers
> >> `Allan
> >> _______________________________________________
> >> webkit-qt mailing list
> >> webkit-qt at lists.webkit.org
> >> http://lists.webkit.org/mailman/listinfo/webkit-qt
> > 
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