usr/local/MATLAB/R2015a/simulink/include Ignoring nonexistent directory '/usr/local/include/x86_64-linux-gnu' GGC heuristics: -param ggc-min-expand=100 -param ggc-min-heapsize=131072 imultiarch x86_64-linux-gnu -D_REENTRANT -D MX_COMPAT_32 -D _GNU_SOURCE -D MATLAB_MEX_FILE -D NDEBUG path/to/test4.c -quiet -dumpbase test4.c -mtune=generic -march=x86-64 -auxbase-strip /tmp/mex_198714460457975_3922/test4.o -O0 -ansi -version -fexceptions -fPIC -fno-omit-frame-pointer -fstack-protector -o /tmp/ccxDOA5f.s

usr/lib/gcc/x86_64-linux-gnu/4.7/cc1 -quiet -v -I /usr/local/MATLAB/R2015a/extern/include -I /usr/local/MATLAB/R2015a/simulink/include -imultilib. src/configure -v -with-pkgversion='Ubuntu/Linaro 4.7.3-2ubuntu1~12.04' -with-bugurl=file:///usr/share/doc/gcc-4.7/README.Bugs -enable-languages=c,c++,go,fortran,objc,obj-c++ -prefix=/usr -program-suffix=-4.7 -enable-shared -enable-linker-build-id -libexecdir=/usr/lib -without-included-gettext -enable-threads=posix -with-gxx-include-dir=/usr/include/c++/4.7 -libdir=/usr/lib -enable-nls -with-sysroot=/ -enable-clocale=gnu -enable-libstdcxx-debug -enable-libstdcxx-time=yes -enable-gnu-unique-object -enable-plugin -with-system-zlib -enable-objc-gc -enable-multiarch -disable-werror -with-arch-32=i686 -with-abi=m64 -with-multilib-list=m32,m64 -with-tune=generic -enable-checking=release -build=x86_64-linux-gnu -host=x86_64-linux-gnu -target=x86_64-linux-gnu

(For reference: Ubuntu 12.04 (Precise Pangolin) 64 bit and GCC 4.7.3) /usr/bin/gcc -c -DMX_COMPAT_32 -D_GNU_SOURCE -DMATLAB_MEX_FILE -I'/usr/local/MATLAB/R2015a/extern/include' -I'/usr/local/MATLAB/R2015a/simulink/include' -ansi -fexceptions -fPIC -fno-omit-frame-pointer -pthread -O0 -DNDEBUG path/to/test4.c -o /tmp/mex_198714460457975_3922/test4.o -vĬonfigured with. Why is this so slow? Is there a way I can make this faster? This has been running for hours, and as you can see, optimization is already disabled (-O0).

Here is the command I am running and the output to screen, below. The C file is around 20 MB (available from the GCC bug tracker if you want to play around with it). I am trying to compile a large C file (specifically for MATLAB mexing).

Matlab r2015a linux