From: Brian Paul
+The Gallium llvmpipe driver is a software rasterizer that uses LLVM to
+do runtime code generation.
+Shaders, point/line/triangle rasterization and vertex processing are
+implemented with LLVM IR which is translated to x86 or x86-64 machine
+code.
+Also, the driver is multithreaded to take advantage of multiple CPU cores
+(up to 8 at this time).
+It's the fastest software rasterizer for Mesa.
+
Support for sse2 is strongly encouraged. Support for ssse3, and sse4.1 will
yield the most efficient code. The less features the CPU has the more
likely is that you ran into underperforming, buggy, or incomplete code.
-
+
See /proc/cpuinfo to know what your CPU supports.
-
- - LLVM. Version 2.8 recommended. 2.6 or later required.
-
- NOTE: LLVM 2.8 and earlier will not work on systems that support the
+
+ NOTE: LLVM 2.8 and earlier will not work on systems that support the
Intel AVX extensions (e.g. Sandybridge). LLVM's code generator will
fail when trying to emit AVX instructions. This was fixed in LLVM 2.9.
-
+
For Linux, on a recent Debian based distribution do:
-
+ Introduction
+
+Requirements
+
+
+
aptitude install llvm-dev
-
+
+ For a RPM-based distribution do:
+
+ yum install llvm-devel ++ +
For Windows download pre-built MSVC 9.0 or MinGW binaries from http://people.freedesktop.org/~jrfonseca/llvm/ and set the LLVM environment variable to the extracted path. +
+For MSVC there are two set of binaries: llvm-x.x-msvc32mt.7z and llvm-x.x-msvc32mtd.7z . +
+You have to set the LLVM=/path/to/llvm-x.x-msvc32mtd env var when passing debug=yes to scons, and LLVM=/path/to/llvm-x.x-msvc32mt when building with debug=no. This is necessary as LLVM builds as static library so the chosen MS CRT must match. +
+ - - scons (optional) +scons build=debug libgl-xlib +Alternatively, you can build it with GNU make, if you prefer, by invoking it as +
make linux-llvm +but the rest of these instructions assume that scons is used. For windows is everything the except except the winsys: +
scons build=debug libgl-gdi ++ -Using -===== +
build/foo/gallium/targets/libgl-xlib/libGL.so ++or +
+ lib/gallium/libGL.so +To use it set the LD_LIBRARY_PATH environment variable accordingly. @@ -72,19 +123,20 @@ replacing the native ICD driver, but it's quite an advanced usage, so if you need to ask, don't even try it. -Profiling -========= +
scons build=profileThis will ensure that frame pointers are used both in C and JIT functions, and that no tail call optimizations are done by gcc. - To better profile JIT code you'll need to build LLVM with oprofile integration. ++
./configure \ --prefix=$install_dir \ --enable-optimized \ @@ -96,43 +148,57 @@ To better profile JIT code you'll need to build LLVM with oprofile integration. make -C "$build_dir" install find "$install_dir/lib" -iname '*.a' -print0 | xargs -0 strip --strip-debug +The you should define +
export LLVM=/path/to/llvm-2.6-profile +and rebuild. -Unit testing -============ +
Building will also create several unit tests in build/linux-???-debug/gallium/drivers/llvmpipe: +
- - lp_test_blend: blending - - lp_test_conv: SIMD vector conversion - - lp_test_format: pixel unpacking/packing + +Some of this tests can output results and benchmarks to a tab-separated-file for posterior analysis, e.g.: - +
+build/linux-x86_64-debug/gallium/drivers/llvmpipe/lp_test_blend -o blend.tsv +-Development Notes -================= +