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Currently the liveness analysis pass would extend a live interval up to the top of the program when no unconditional and complete definition of the variable is found that dominates all of its uses. This can lead to a serious performance problem in shaders containing many partial writes, like scalar arithmetic, FP64 and soon FP16 operations. The number of oversize live intervals in such workloads can cause the compilation time of the shader to explode because of the worse than quadratic behavior of the register allocator and scheduler when running out of registers, and it can also cause the running time of the shader to explode due to the amount of spilling it leads to, which is orders of magnitude slower than GRF memory. This patch fixes it by computing the intersection of our current live intervals with the subset of the program that can possibly be reached from any definition of the variable. Extending the storage allocation of the variable beyond that is pretty useless because its value is guaranteed to be undefined at a point that cannot be reached from any definition. According to Jason, this improves performance of the subgroup Vulkan CTS tests significantly (e.g. the runtime of the dvec4 broadcast test improves by nearly 50x). No significant change in the running time of shader-db (with 5% statistical significance). shader-db results on IVB: total cycles in shared programs: 61108780 -> 60932856 (-0.29%) cycles in affected programs: 16335482 -> 16159558 (-1.08%) helped: 5121 HURT: 4347 total spills in shared programs: 1309 -> 1288 (-1.60%) spills in affected programs: 249 -> 228 (-8.43%) helped: 3 HURT: 0 total fills in shared programs: 1652 -> 1597 (-3.33%) fills in affected programs: 262 -> 207 (-20.99%) helped: 4 HURT: 0 LOST: 2 GAINED: 209 shader-db results on BDW: total cycles in shared programs: 67617262 -> 67361220 (-0.38%) cycles in affected programs: 23397142 -> 23141100 (-1.09%) helped: 8045 HURT: 6488 total spills in shared programs: 1456 -> 1252 (-14.01%) spills in affected programs: 465 -> 261 (-43.87%) helped: 3 HURT: 0 total fills in shared programs: 1720 -> 1465 (-14.83%) fills in affected programs: 471 -> 216 (-54.14%) helped: 4 HURT: 0 LOST: 2 GAINED: 162 shader-db results on SKL: total cycles in shared programs: 65436248 -> 65245186 (-0.29%) cycles in affected programs: 22560936 -> 22369874 (-0.85%) helped: 8457 HURT: 6247 total spills in shared programs: 437 -> 437 (0.00%) spills in affected programs: 0 -> 0 helped: 0 HURT: 0 total fills in shared programs: 870 -> 854 (-1.84%) fills in affected programs: 16 -> 0 helped: 1 HURT: 0 LOST: 0 GAINED: 107 Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
File: docs/README.WIN32 Last updated: 21 June 2013 Quick Start ----- ----- Windows drivers are build with SCons. Makefiles or Visual Studio projects are no longer shipped or supported. Run scons libgl-gdi to build gallium based GDI driver. This will work both with MSVS or Mingw. Windows Drivers ------- ------- At this time, only the gallium GDI driver is known to work. Source code also exists in the tree for other drivers in src/mesa/drivers/windows, but the status of this code is unknown. Recipe ------ Building on windows requires several open-source packages. These are steps that work as of this writing. - install python 2.7 - install scons (latest) - install mingw, flex, and bison - install pywin32 from here: http://www.lfd.uci.edu/~gohlke/pythonlibs get pywin32-218.4.win-amd64-py2.7.exe - install git - download mesa from git see https://www.mesa3d.org/repository.html - run scons General ------- After building, you can copy the above DLL files to a place in your PATH such as $SystemRoot/SYSTEM32. If you don't like putting things in a system directory, place them in the same directory as the executable(s). Be careful about accidentially overwriting files of the same name in the SYSTEM32 directory. The DLL files are built so that the external entry points use the stdcall calling convention. Static LIB files are not built. The LIB files that are built with are the linker import files associated with the DLL files. The si-glu sources are used to build the GLU libs. This was done mainly to get the better tessellator code. If you have a Windows-related build problem or question, please post to the mesa-dev or mesa-users list.