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

[jocelyn.turcotte at nokia.com]

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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