Dear all, Until a few days ago, I was using: - Old mingw32 shipped with Qt (gcc 4.4.0) for 32bit builds - Mingw-w64 x86_64 rubenvb build (gcc 4.7.1)
My code (an intensive calculation) was running at similar speed with 32-bit and 64-bit build (speed index : 510-520, only a few % difference between both) I just switched to 4.8.0 rubenvb builds for both 32bit and 64bit builds Here are the results: - 32bits : speed index around 420 (strong decrease) - 64bits : speed index around 630 (Wow! That's a good surprise!) Besides the fact that 4.8.0 has fantastic performances in 64bit (now it beats MSVC fingers in the nose), do you have an idea why the 32bit build is significantly slower? I use the same exact compiler options in all cases: g++ -c -O3 -mfpmath=sse -march=k8-sse3 -mtune=k8-sse3 -msse3 -ftree-vectorize -mpreferred-stack-boundary=4 -fno-math-errno -funsafe-math-optimizations -fno-trapping-math -fno-exceptions -g -frtti -fexceptions -mthreads -Wall -DUNICODE -DQT_LARGEFILE_SUPPORT -DOPENEXR_SUPPORT -DOCEAN_MAJOR_VERSION=1 -DOCEAN_MINOR_VERSION=3 -DOCEAN_BUGFIX_VERSION=0 -DAPP_REVISION=\"393\" -DQT_DLL -DQT_NO_DEBUG -DQT_XML_LIB -DQT_GUI_LIB -DQT_NETWORK_LIB -DQT_CORE_LIB -DQT_HAVE_MMX -DQT_HAVE_SSE -DQT_HAVE_MMXEXT -DQT_HAVE_SSE2 -DQT_THREAD_SUPPORT The symbols (-g) are enabled for profiling. Thanks! Etienne ------------------------------------------------------------------------------ Own the Future-Intel® Level Up Game Demo Contest 2013 Rise to greatness in Intel's independent game demo contest. Compete for recognition, cash, and the chance to get your game on Steam. $5K grand prize plus 10 genre and skill prizes. Submit your demo by 6/6/13. http://p.sf.net/sfu/intel_levelupd2d _______________________________________________ Mingw-w64-public mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/mingw-w64-public
