On 27.01.2015 04:20, Dieter Nützel wrote:
make[1]: Leaving directory '/opt/llvm/bindings' llvm[0]: ***** Completed Debug+Asserts Build llvm[0]: ***** Note: Debug build can be 10 times slower than an llvm[0]: ***** optimized build. Use make ENABLE_OPTIMIZED=1 to llvm[0]: ***** make an optimized build. Alternatively you can llvm[0]: ***** configure with --enable-optimized. 304.322u 15.792s 1:50.25 290.3% 0+0k 6156432+1518784io 942pf+0w
FWIW, I use these debug vs. optimization related options for building LLVM:
'--enable-optimized' '--with-optimize-option=-O2 -ftree-vectorize -march=amdfam10 -mtune=native' '--enable-assertions' '--enable-debug-runtime' '--enable-debug-symbols' 'CPPFLAGS=-fno-omit-frame-pointer' 'CFLAGS=-fno-omit-frame-pointer' 'CXXFLAGS=-fno-omit-frame-pointer'
That gives good performance while preserving assertions and debugging symbols. -march=amdfam10 (as opposed to -march=native or a newer AMD CPU family) avoids generating machine code which valgrind can't handle, and -fno-omit-frame-pointer allows profile call graphs to make sense.
Second: 'make -j 4' do NOT work in the first run. --- Known?
Not to me.