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This is an automatically generated e-mail. To reply, visit:
<a href="http://git.reviewboard.kde.org/r/101378/">http://git.reviewboard.kde.org/r/101378/</a>
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<div>Review request for Marble.</div>
<div>By Bernhard Beschow.</div>
<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Description </h1>
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<pre style="margin: 0; padding: 0; white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;">This patch changes the scanline texture mappers to render textures with multiple threads.
The number of threads is determined using QThread::idealThreadCount().
The patch consists of two commits [1], where the first one refactors and cleans up the texture mappers, whereas the second one introduces the threading.
In the first commit, a class named ScanlineTextureMapperContext is introduced, which holds the state for performing scanline texture mapping. It was factored out of the AbstractScanlineTextureMapper class, which is now named "TextureMapperInterface". Fresh ScanlineTextureMapperContexts are created upon every rendering action, which is cleaner than the former approach of reinitializing all rendering attributes in AbstractScanlineTextureMapper::setRadius(). Finally, the patch constifies many variables in the texture mappers and removes some unneeded code.
In the second commit, threads are used for texture rendering. Almost all rendering logic has been moved into QRunnable implementations, which are recreated for every frame. Since each QRunnable instantiates its own ScanlineTextureMapperContext, the contexts are recreated for every frame as well.
Due to synchronization overhead for tile acces, the patch may cause a small performance regression. I couldn't measure any big difference on a single-core machine, though.
[1] https://github.com/shentok/marble/tree/threaded-rendering</pre>
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<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Testing </h1>
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<pre style="margin: 0; padding: 0; white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;">Here are some numbers of a benchmark using OSM:
I get the following speedups on an Atom N270 (two Hyperthreads):
o globe projection:
low quality: ~29 -> ~32 fps
outline quality: ~20 -> ~25 fps
high quality: ~5 -> ~7 fps
o flat projection:
low quality: ~33 -> ~36 fps
outline quality: ~23 -> ~26 fps
high quality: ~7 -> ~9 fps
o mercator projection:
low quality: ~32 -> ~35 fps
outline quality: ~22 -> ~26 fps
high quality: ~7 -> ~9 fps
Earthwings gets the following speedups for globe projection on an Intel(R) Core(TM)2 Quad CPU Q8200 @ 2.33GHz (four "real" threads):
low quality: ~57 -> ~66 fps
outline quality: ~37 -> ~48 fps
high quality: ~14 -> ~30 fps
I get about the same results before and after the patch is applied on a single-core machine.</pre>
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<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Diffs</b> </h1>
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<li>src/lib/AbstractScanlineTextureMapper.h <span style="color: grey">(1998db0)</span></li>
<li>src/lib/AbstractScanlineTextureMapper.cpp <span style="color: grey">(8acf57c)</span></li>
<li>src/lib/CMakeLists.txt <span style="color: grey">(f5d49c0)</span></li>
<li>src/lib/EquirectScanlineTextureMapper.h <span style="color: grey">(05e6639)</span></li>
<li>src/lib/EquirectScanlineTextureMapper.cpp <span style="color: grey">(8f697cc)</span></li>
<li>src/lib/MarbleMap.cpp <span style="color: grey">(6f5f54f)</span></li>
<li>src/lib/MercatorScanlineTextureMapper.h <span style="color: grey">(a79d1c8)</span></li>
<li>src/lib/MercatorScanlineTextureMapper.cpp <span style="color: grey">(bdf9b0c)</span></li>
<li>src/lib/ScanlineTextureMapperContext.h <span style="color: grey">(PRE-CREATION)</span></li>
<li>src/lib/ScanlineTextureMapperContext.cpp <span style="color: grey">(PRE-CREATION)</span></li>
<li>src/lib/SphericalScanlineTextureMapper.h <span style="color: grey">(f336282)</span></li>
<li>src/lib/SphericalScanlineTextureMapper.cpp <span style="color: grey">(583630a)</span></li>
<li>src/lib/StackedTileLoader.cpp <span style="color: grey">(b67cb98)</span></li>
<li>src/lib/TextureLayer.cpp <span style="color: grey">(d98f712)</span></li>
<li>src/lib/TextureMapperInterface.h <span style="color: grey">(PRE-CREATION)</span></li>
<li>src/lib/TextureMapperInterface.cpp <span style="color: grey">(PRE-CREATION)</span></li>
<li>src/lib/TileLoader.cpp <span style="color: grey">(1b85dda)</span></li>
<li>src/lib/TileScalingTextureMapper.h <span style="color: grey">(2c70dad)</span></li>
<li>src/lib/TileScalingTextureMapper.cpp <span style="color: grey">(2ec719f)</span></li>
<li>src/lib/global.h <span style="color: grey">(a5c25fb)</span></li>
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<p><a href="http://git.reviewboard.kde.org/r/101378/diff/" style="margin-left: 3em;">View Diff</a></p>
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