Hi,
> I doubt decoding is the issue. Except for the GIF format, the decoding
> of images is done by the usual libraries (libjpeg, libpng).
>
> My guess is color conversion could be an issue depending on the target
> color format on your directfb. If the color format on 32 bits, the
> problem could also be on composition or the final color conversion to
> the target framebuffer.
> (If the problem is on color conversion, scrolling is likely to be slower
> than usual as well).
>
> I suggest you to profile your application (oprofile generally works
> great on Linux devices) and share the results here.
>
>
I've sent a reply but it was blocked since it was a bit huge.
so here are the profiling results done using the "perf" tool.
# Samples: 3756
#
# Overhead Samples Command
Shared Object Symbol
# ........ .......... ..............
.........................................................................
......
#
57.11% 2145 swapper [kernel] [k]
default_idle
2.21% 83 browser
/home/rahmanih/qt-4.7.2_21072011/lib/libQtWebKit.so.4.7.2
[.] WebCore::DeprecatedPtrListImplIterator::operator++()
1.76% 66 browser
/home/rahmanih/qt-4.7.2_21072011/lib/libQtWebKit.so.4.7.2
[.] WebCore::RenderBlock::leftRelOffset(int, int, bool, int*) const
1.60% 60 browser
/home/rahmanih/qt-4.7.2_21072011/lib/libQtWebKit.so.4.7.2
[.] WebCore::RenderBlock::rightRelOffset(int, int, bool, int*) const
0.96% 36 browser
/home/rahmanih/qt-4.7.2_21072011/lib/libQtWebKit.so.4.7.2
[.] WebCore::DeprecatedPtrListImplIterator::current() const
0.80% 30 browser
/home/rahmanih/qt-4.7.2_21072011/lib/libQtWebKit.so.4.7.2
[.] WebCore::RenderLayer::paintLayer(WebCore::RenderLayer*,
WebCore::GraphicsContext*, WebCore::IntRect const&, unsigned int,
WebCore::RenderObject*, WTF::HashMap<WebCore::OverlapTestRequestClient*,
WebCore::IntRect, WTF::PtrHash<WebCore::OverlapTestRequestClient*>,
WTF::HashTraits<WebCore::OverlapTestRequestClient*>,
WTF::HashTraits<WebCore::IntRect> >*, unsigned int)
0.77% 29 browser [kernel]
[k] 0x000000c1152b6e
0.59% 22 browser
/home/rahmanih/qt-4.7.2_21072011/lib/libQtWebKit.so.4.7.2
[.] WebCore::InlineBox::height() const
0.53% 20 browser
/home/rahmanih/qt-4.7.2_21072011/lib/libQtGui.so.4.7.2
[.] INTERPOLATE_PIXEL_255(unsigned int, unsigned int, unsigned int, unsigned
int)
0.51% 19 browser
/home/rahmanih/qt-4.7.2_21072011/lib/libQtWebKit.so.4.7.2
[.]
WebCore::RenderBlock::findNextLineBreak(WebCore::BidiResolver<WebCore::InlineIterator,
WebCore::BidiRun>&, bool, bool&, bool&, WebCore::EClear*)
0.48% 18 browser /lib/ld-2.10.1.so
[.] do_lookup_x
0.43% 16 browser /lib/libc-2.10.1.so
[.] _int_malloc
0.43% 16 browser /home/rahmanih/qt-4.7.2
I really can't understand why the 51% of the time is spent in the kernel as
"idle" ?
any idea on that ?
regards.
Haithem.
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