i965/gen4-6: Use the generic ISL-based path for texture surfaces
[mesa.git] / docs / llvmpipe.html
1 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
2 <html lang="en">
3 <head>
4 <meta http-equiv="content-type" content="text/html; charset=utf-8">
5 <title>llvmpipe</title>
6 <link rel="stylesheet" type="text/css" href="mesa.css">
7 </head>
8 <body>
9
10 <div class="header">
11 <h1>The Mesa 3D Graphics Library</h1>
12 </div>
13
14 <iframe src="contents.html"></iframe>
15 <div class="content">
16
17 <h1>Introduction</h1>
18
19 <p>
20 The Gallium llvmpipe driver is a software rasterizer that uses LLVM to
21 do runtime code generation.
22 Shaders, point/line/triangle rasterization and vertex processing are
23 implemented with LLVM IR which is translated to x86 or x86-64 machine
24 code.
25 Also, the driver is multithreaded to take advantage of multiple CPU cores
26 (up to 8 at this time).
27 It's the fastest software rasterizer for Mesa.
28 </p>
29
30
31 <h1>Requirements</h1>
32
33 <ul>
34 <li>
35 <p>An x86 or amd64 processor; 64-bit mode recommended.</p>
36 <p>
37 Support for SSE2 is strongly encouraged. Support for SSSE3 and SSE4.1 will
38 yield the most efficient code. The fewer features the CPU has the more
39 likely is that you run into underperforming, buggy, or incomplete code.
40 </p>
41 <p>
42 See /proc/cpuinfo to know what your CPU supports.
43 </p>
44 </li>
45 <li>
46 <p>LLVM: version 3.4 recommended; 3.3 or later required.</p>
47 <p>
48 For Linux, on a recent Debian based distribution do:
49 </p>
50 <pre>
51 aptitude install llvm-dev
52 </pre>
53 <p>
54 For a RPM-based distribution do:
55 </p>
56 <pre>
57 yum install llvm-devel
58 </pre>
59
60 <p>
61 For Windows you will need to build LLVM from source with MSVC or MINGW
62 (either natively or through cross compilers) and CMake, and set the LLVM
63 environment variable to the directory you installed it to.
64
65 LLVM will be statically linked, so when building on MSVC it needs to be
66 built with a matching CRT as Mesa, and you'll need to pass
67 <code>-DLLVM_USE_CRT_xxx=yyy</code> as described below.
68 </p>
69
70 <table border="1">
71 <tr>
72 <th rowspan="2">LLVM build-type</th>
73 <th colspan="2" align="center">Mesa build-type</th>
74 </tr>
75 <tr>
76 <th>debug,checked</th>
77 <th>release,profile</th>
78 </tr>
79 <tr>
80 <th>Debug</th>
81 <td><code>-DLLVM_USE_CRT_DEBUG=MTd</code></td>
82 <td><code>-DLLVM_USE_CRT_DEBUG=MT</code></td>
83 </tr>
84 <tr>
85 <th>Release</th>
86 <td><code>-DLLVM_USE_CRT_RELEASE=MTd</code></td>
87 <td><code>-DLLVM_USE_CRT_RELEASE=MT</code></td>
88 </tr>
89 </table>
90
91 <p>
92 You can build only the x86 target by passing -DLLVM_TARGETS_TO_BUILD=X86
93 to cmake.
94 </p>
95 </li>
96
97 <li>
98 <p>scons (optional)</p>
99 </li>
100 </ul>
101
102
103 <h1>Building</h1>
104
105 To build everything on Linux invoke scons as:
106
107 <pre>
108 scons build=debug libgl-xlib
109 </pre>
110
111 Alternatively, you can build it with GNU make, if you prefer, by invoking it as
112
113 <pre>
114 make linux-llvm
115 </pre>
116
117 but the rest of these instructions assume that scons is used.
118
119 For Windows the procedure is similar except the target:
120
121 <pre>
122 scons platform=windows build=debug libgl-gdi
123 </pre>
124
125
126 <h1>Using</h1>
127
128 <h2>Linux</h2>
129
130 <p>On Linux, building will create a drop-in alternative for libGL.so into</p>
131
132 <pre>
133 build/foo/gallium/targets/libgl-xlib/libGL.so
134 </pre>
135 or
136 <pre>
137 lib/gallium/libGL.so
138 </pre>
139
140 <p>To use it set the LD_LIBRARY_PATH environment variable accordingly.</p>
141
142 <p>For performance evaluation pass build=release to scons, and use the corresponding
143 lib directory without the "-debug" suffix.</p>
144
145
146 <h2>Windows</h2>
147
148 <p>
149 On Windows, building will create
150 <code>build/windows-x86-debug/gallium/targets/libgl-gdi/opengl32.dll</code>
151 which is a drop-in alternative for system's <code>opengl32.dll</code>. To use
152 it put it in the same directory as your application. It can also be used by
153 replacing the native ICD driver, but it's quite an advanced usage, so if you
154 need to ask, don't even try it.
155 </p>
156
157 <p>
158 There is however an easy way to replace the OpenGL software renderer that comes
159 with Microsoft Windows 7 (or later) with llvmpipe (that is, on systems without
160 any OpenGL drivers):
161 </p>
162
163 <ul>
164 <li><p>copy build/windows-x86-debug/gallium/targets/libgl-gdi/opengl32.dll to C:\Windows\SysWOW64\mesadrv.dll</p></li>
165 <li><p>load this registry settings:</p>
166 <pre>REGEDIT4
167
168 ; http://technet.microsoft.com/en-us/library/cc749368.aspx
169 ; http://www.msfn.org/board/topic/143241-portable-windows-7-build-from-winpe-30/page-5#entry942596
170 [HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Windows NT\CurrentVersion\OpenGLDrivers\MSOGL]
171 "DLL"="mesadrv.dll"
172 "DriverVersion"=dword:00000001
173 "Flags"=dword:00000001
174 "Version"=dword:00000002
175 </pre>
176 </li>
177 <li>Ditto for 64 bits drivers if you need them.</li>
178 </ul>
179
180
181 <h1>Profiling</h1>
182
183 <p>
184 To profile llvmpipe you should build as
185 </p>
186 <pre>
187 scons build=profile &lt;same-as-before&gt;
188 </pre>
189
190 <p>
191 This will ensure that frame pointers are used both in C and JIT functions, and
192 that no tail call optimizations are done by gcc.
193 </p>
194
195 <h2>Linux perf integration</h2>
196
197 <p>
198 On Linux, it is possible to have symbol resolution of JIT code with <a href="http://perf.wiki.kernel.org/">Linux perf</a>:
199 </p>
200
201 <pre>
202 perf record -g /my/application
203 perf report
204 </pre>
205
206 <p>
207 When run inside Linux perf, llvmpipe will create a /tmp/perf-XXXXX.map file with
208 symbol address table. It also dumps assembly code to /tmp/perf-XXXXX.map.asm,
209 which can be used by the bin/perf-annotate-jit script to produce disassembly of
210 the generated code annotated with the samples.
211 </p>
212
213 <p>You can obtain a call graph via
214 <a href="http://code.google.com/p/jrfonseca/wiki/Gprof2Dot#linux_perf">Gprof2Dot</a>.</p>
215
216
217 <h1>Unit testing</h1>
218
219 <p>
220 Building will also create several unit tests in
221 build/linux-???-debug/gallium/drivers/llvmpipe:
222 </p>
223
224 <ul>
225 <li> lp_test_blend: blending
226 <li> lp_test_conv: SIMD vector conversion
227 <li> lp_test_format: pixel unpacking/packing
228 </ul>
229
230 <p>
231 Some of this tests can output results and benchmarks to a tab-separated-file
232 for posterior analysis, e.g.:
233 </p>
234 <pre>
235 build/linux-x86_64-debug/gallium/drivers/llvmpipe/lp_test_blend -o blend.tsv
236 </pre>
237
238
239 <h1>Development Notes</h1>
240
241 <ul>
242 <li>
243 When looking to this code by the first time start in lp_state_fs.c, and
244 then skim through the lp_bld_* functions called in there, and the comments
245 at the top of the lp_bld_*.c functions.
246 </li>
247 <li>
248 The driver-independent parts of the LLVM / Gallium code are found in
249 src/gallium/auxiliary/gallivm/. The filenames and function prefixes
250 need to be renamed from "lp_bld_" to something else though.
251 </li>
252 <li>
253 We use LLVM-C bindings for now. They are not documented, but follow the C++
254 interfaces very closely, and appear to be complete enough for code
255 generation. See
256 <a href="http://npcontemplation.blogspot.com/2008/06/secret-of-llvm-c-bindings.html">
257 this stand-alone example</a>. See the llvm-c/Core.h file for reference.
258 </li>
259 </ul>
260
261 <h1 id="recommended_reading">Recommended Reading</h1>
262
263 <ul>
264 <li>
265 <p>Rasterization</p>
266 <ul>
267 <li><a href="http://www.cs.unc.edu/~olano/papers/2dh-tri/">Triangle Scan Conversion using 2D Homogeneous Coordinates</a></li>
268 <li><a href="http://www.drdobbs.com/parallel/rasterization-on-larrabee/217200602">Rasterization on Larrabee</a> (<a href="http://devmaster.net/posts/2887/rasterization-on-larrabee">DevMaster copy</a>)</li>
269 <li><a href="http://devmaster.net/posts/6133/rasterization-using-half-space-functions">Rasterization using half-space functions</a></li>
270 <li><a href="http://devmaster.net/posts/6145/advanced-rasterization">Advanced Rasterization</a></li>
271 <li><a href="http://fgiesen.wordpress.com/2013/02/17/optimizing-sw-occlusion-culling-index/">Optimizing Software Occlusion Culling</a></li>
272 </ul>
273 </li>
274 <li>
275 <p>Texture sampling</p>
276 <ul>
277 <li><a href="http://chrishecker.com/Miscellaneous_Technical_Articles#Perspective_Texture_Mapping">Perspective Texture Mapping</a></li>
278 <li><a href="http://www.flipcode.com/archives/Texturing_As_In_Unreal.shtml">Texturing As In Unreal</a></li>
279 <li><a href="http://www.gamasutra.com/view/feature/3301/runtime_mipmap_filtering.php">Run-Time MIP-Map Filtering</a></li>
280 <li><a href="http://alt.3dcenter.org/artikel/2003/10-26_a_english.php">Will "brilinear" filtering persist?</a></li>
281 <li><a href="http://ixbtlabs.com/articles2/gffx/nv40-rx800-3.html">Trilinear filtering</a></li>
282 <li><a href="http://devmaster.net/posts/12785/texture-swizzling">Texture Swizzling</a></li>
283 </ul>
284 </li>
285 <li>
286 <p>SIMD</p>
287 <ul>
288 <li><a href="http://www.cdl.uni-saarland.de/projects/wfv/#header4">Whole-Function Vectorization</a></li>
289 </ul>
290 </li>
291 <li>
292 <p>Optimization</p>
293 <ul>
294 <li><a href="http://www.drdobbs.com/optimizing-pixomatic-for-modern-x86-proc/184405807">Optimizing Pixomatic For Modern x86 Processors</a></li>
295 <li><a href="http://www.intel.com/content/www/us/en/architecture-and-technology/64-ia-32-architectures-optimization-manual.html">Intel 64 and IA-32 Architectures Optimization Reference Manual</a></li>
296 <li><a href="http://www.agner.org/optimize/">Software optimization resources</a></li>
297 <li><a href="http://software.intel.com/en-us/articles/intel-intrinsics-guide">Intel Intrinsics Guide</a><li>
298 </ul>
299 </li>
300 <li>
301 <p>LLVM</p>
302 <ul>
303 <li><a href="http://llvm.org/docs/LangRef.html">LLVM Language Reference Manual</a></li>
304 <li><a href="http://npcontemplation.blogspot.co.uk/2008/06/secret-of-llvm-c-bindings.html">The secret of LLVM C bindings</a></li>
305 </ul>
306 </li>
307 <li>
308 <p>General</p>
309 <ul>
310 <li><a href="http://fgiesen.wordpress.com/2011/07/09/a-trip-through-the-graphics-pipeline-2011-index/">A trip through the Graphics Pipeline</a></li>
311 <li><a href="http://msdn.microsoft.com/en-us/library/gg615082.aspx#architecture">WARP Architecture and Performance</a></li>
312 </ul>
313 </li>
314 </ul>
315
316 </div>
317 </body>
318 </html>