docs/cell.html - platform/external/mesa3d - Git at Google

 <HTML>

 <TITLE>Cell Driver</TITLE>

 <link rel="stylesheet" type="text/css" href="mesa.css"></head>

 <BODY>

 <H1>Mesa/Gallium Cell Driver</H1>

 <p>
 The Mesa
 <a href="http://en.wikipedia.org/wiki/Cell_%28microprocessor%29" target="_parent">Cell</a>
 driver is part of the
 <a href="http://wiki.freedesktop.org/wiki/Software/gallium" target="_parent">Gallium3D</a>
 architecture.
 Tungsten Graphics did the original implementation of the Cell driver.
 </p>


 <H2>Source Code</H2>

 <p>
 The latest Cell driver source code is on the master branch of the Mesa
 git repository.
 </p>
 <p>
 To build the driver you'll need the IBM Cell SDK (version 2.1 or 3.0).
 To use the driver you'll need a Cell system, such as a PS3 running Linux,
 or the Cell Simulator (untested, though).
 </p>

 <p>
 If using Cell SDK 2.1, see the configs/linux-cell file for some
 special changes.
 </p>

 <p>
 To compile the code, run <code>make linux-cell</code>.
 Or to build in debug mode, run <code>make linux-cell-debug</code>.
 </p>

 <p>
 To use the library, make sure your current directory is the top of the
 Mesa tree, then set <code>LD_LIBRARY_PATH</code> like this:
 <pre>
   export LD_LIBRARY_PATH=$PWD/lib/gallium:$PWD/lib/
 </pre>

 <p>
 Verify that the Cell driver is being used by running
 <code>progs/xdemos/glxinfo</code> and looking for:
 <pre>
   OpenGL renderer string: Gallium 0.3, Cell on Xlib
 </pre>


 <H2>Driver Implementation Summary</H2>

 <p>
 Rasterization is parallelized across the SPUs in a tiled-based manner.
 Batches of transformed triangles are sent to the SPUs (actually, pulled by from
 main memory by the SPUs).
 Each SPU loops over a set of 32x32-pixel screen tiles, rendering the triangles
 into each tile.
 Because of the limited SPU memory, framebuffer tiles are paged in/out of
 SPU local store as needed.
 Similarly, textures are tiled and brought into local store as needed.
 </p>


 <H2>Status</H2>

 <p>
 As of October 2008, the driver runs quite a few OpenGL demos.
 Features that work include:
 </p>
 <ul>
 <li>Point/line/triangle rendering, glDrawPixels
 <li>2D, NPOT and cube texture maps with nearest/linear/mipmap filtering
 <li>Dynamic SPU code generation for fragment shaders, but not complete
 <li>Dynamic SPU code generation for fragment ops (blend, Z-test, etc), but not complete
 <li>Dynamic PPU/PPC code generation for vertex shaders, but not complete
 </ul>
 <p>
 Performance has recently improved with the addition of PPC code generation
 for vertex shaders, but the code quality isn't too great yet.
 </p>
 <p>
 Another bottleneck is SwapBuffers.  It may be the limiting factor for
 many simple GL tests.
 </p>


 <H2>Debug Options</H2>

 <p>
 The CELL_DEBUG env var can be set to a comma-separated list of one or
 more of the following debug options:
 </p>
 <ul>
 <li><b>checker</b> - use a different background clear color for each SPU.
    This lets you see which SPU is rendering which screen tiles.
 <li><b>sync</b> - wait/synchronize after each DMA transfer
 <li><b>asm</b> - print generated SPU assembly code to stdout
 <li><b>fragops</b> - emit fragment ops debug messages
 <li><b>fragopfallback</b> - don't use codegen for fragment ops
 <li><b>cmd</b> - print SPU commands as their received
 <li><b>cache</b> - print texture cache statistics when program exits
 </ul>
 <p>
 Note that some of these options may only work for linux-cell-debug builds.
 </p>

 <p>
 If the GALLIUM_NOPPC env var is set, PPC code generation will not be used
 and vertex shaders will be run with the TGSI interpreter.
 </p>
 <p>
 If the GALLIUM_NOCELL env var is set, the softpipe driver will be used
 intead of the Cell driver.
 This is useful for comparison/validation.
 </p>


 <H2>Contributing</H2>

 <p>
 If you're interested in contributing to the effort, familiarize yourself
 with the code, join the <a href="lists.html">mesa3d-dev mailing list</a>,
 and describe what you'd like to do.
 </p>


 </BODY>
 </HTML>
	<HTML>

	<TITLE>Cell Driver</TITLE>

	<link rel="stylesheet" type="text/css" href="mesa.css"></head>

	<BODY>

	<H1>Mesa/Gallium Cell Driver</H1>

	<p>
	The Mesa
	<a href="http://en.wikipedia.org/wiki/Cell_%28microprocessor%29" target="_parent">Cell</a>
	driver is part of the
	<a href="http://wiki.freedesktop.org/wiki/Software/gallium" target="_parent">Gallium3D</a>
	architecture.
	Tungsten Graphics did the original implementation of the Cell driver.
	</p>


	<H2>Source Code</H2>

	<p>
	The latest Cell driver source code is on the master branch of the Mesa
	git repository.
	</p>
	<p>
	To build the driver you'll need the IBM Cell SDK (version 2.1 or 3.0).
	To use the driver you'll need a Cell system, such as a PS3 running Linux,
	or the Cell Simulator (untested, though).
	</p>

	<p>
	If using Cell SDK 2.1, see the configs/linux-cell file for some
	special changes.
	</p>

	<p>
	To compile the code, run <code>make linux-cell</code>.
	Or to build in debug mode, run <code>make linux-cell-debug</code>.
	</p>

	<p>
	To use the library, make sure your current directory is the top of the
	Mesa tree, then set <code>LD_LIBRARY_PATH</code> like this:
	<pre>
	export LD_LIBRARY_PATH=$PWD/lib/gallium:$PWD/lib/
	</pre>

	<p>
	Verify that the Cell driver is being used by running
	<code>progs/xdemos/glxinfo</code> and looking for:
	<pre>
	OpenGL renderer string: Gallium 0.3, Cell on Xlib
	</pre>


	<H2>Driver Implementation Summary</H2>

	<p>
	Rasterization is parallelized across the SPUs in a tiled-based manner.
	Batches of transformed triangles are sent to the SPUs (actually, pulled by from
	main memory by the SPUs).
	Each SPU loops over a set of 32x32-pixel screen tiles, rendering the triangles
	into each tile.
	Because of the limited SPU memory, framebuffer tiles are paged in/out of
	SPU local store as needed.
	Similarly, textures are tiled and brought into local store as needed.
	</p>


	<H2>Status</H2>

	<p>
	As of October 2008, the driver runs quite a few OpenGL demos.
	Features that work include:
	</p>
	<ul>
	<li>Point/line/triangle rendering, glDrawPixels
	<li>2D, NPOT and cube texture maps with nearest/linear/mipmap filtering
	<li>Dynamic SPU code generation for fragment shaders, but not complete
	<li>Dynamic SPU code generation for fragment ops (blend, Z-test, etc), but not complete
	<li>Dynamic PPU/PPC code generation for vertex shaders, but not complete
	</ul>
	<p>
	Performance has recently improved with the addition of PPC code generation
	for vertex shaders, but the code quality isn't too great yet.
	</p>
	<p>
	Another bottleneck is SwapBuffers. It may be the limiting factor for
	many simple GL tests.
	</p>



	<H2>Debug Options</H2>

	<p>
	The CELL_DEBUG env var can be set to a comma-separated list of one or
	more of the following debug options:
	</p>
	<ul>
	<li><b>checker</b> - use a different background clear color for each SPU.
	This lets you see which SPU is rendering which screen tiles.
	<li><b>sync</b> - wait/synchronize after each DMA transfer
	<li><b>asm</b> - print generated SPU assembly code to stdout
	<li><b>fragops</b> - emit fragment ops debug messages
	<li><b>fragopfallback</b> - don't use codegen for fragment ops
	<li><b>cmd</b> - print SPU commands as their received
	<li><b>cache</b> - print texture cache statistics when program exits
	</ul>
	<p>
	Note that some of these options may only work for linux-cell-debug builds.
	</p>

	<p>
	If the GALLIUM_NOPPC env var is set, PPC code generation will not be used
	and vertex shaders will be run with the TGSI interpreter.
	</p>
	<p>
	If the GALLIUM_NOCELL env var is set, the softpipe driver will be used
	intead of the Cell driver.
	This is useful for comparison/validation.
	</p>



	<H2>Contributing</H2>

	<p>
	If you're interested in contributing to the effort, familiarize yourself
	with the code, join the <a href="lists.html">mesa3d-dev mailing list</a>,
	and describe what you'd like to do.
	</p>


	</BODY>
	</HTML>