[gambit-list] Building Gambit on OS X

[Marc Feeley]

Xcode 6.1.1 was released a little over a month ago, so I decided to do some benchmarking to see how well its C compilers (Apple clang 6.0 and Apple gcc 6.0) compare against GNU gcc 4.9.2 when compiling Gambit.

I configured and built Gambit with

   ./configure --enable-single-host CC="<C_COMPILER>"
   make -j8

I report the build time for each compiler and the execution time of test 4 (which measures the speed of the interpreter, which is indicative of the relative speed of the code generated by Gambit).  Here are the numbers:

  Build          test4         C compiler
  (secs)         (secs)

    60.31        1.30          GNU gcc 4.9.2
  2042.98 (34x)  3.05 (2.3x)   Apple clang 6.0
  1875.56 (31x)  3.08 (2.4x)   Apple gcc 6.0

As can be seen, the Apple C compilers build Gambit in roughly 30 minutes, which is about 30x slower than when using GNU gcc 4.9.2 .  The execution time is also better for GNU gcc, about 2.3x faster.

So on OS X it is clearly advantageous to install GNU gcc when using Gambit.  This can easily be achieved with the homebrew system with the command

   brew install gcc49

Marc

P.S. here is the version information of the compilers:

==============================================================================
GNU gcc 4.9.2:

% /usr/local/Cellar/gcc49/4.9.2/bin/gcc-4.9 -v
Using built-in specs.
COLLECT_GCC=/usr/local/Cellar/gcc49/4.9.2/bin/gcc-4.9
COLLECT_LTO_WRAPPER=/usr/local/Cellar/gcc49/4.9.2/libexec/gcc/x86_64-apple-darwin14.0.0/4.9.2/lto-wrapper
Target: x86_64-apple-darwin14.0.0
Configured with: ../configure --build=x86_64-apple-darwin14.0.0 --prefix=/usr/local/Cellar/gcc49/4.9.2 --enable-languages=c,c++,objc,obj-c++ --program-suffix=-4.9 --with-gmp=/usr/local/opt/gmp4 --with-mpfr=/usr/local/opt/mpfr2 --with-mpc=/usr/local/opt/libmpc08 --with-cloog=/usr/local/opt/cloog018 --with-isl=/usr/local/opt/isl011 --with-system-zlib --enable-version-specific-runtime-libs --enable-libstdcxx-time=yes --enable-stage1-checking --enable-checking=release --enable-lto --disable-werror --with-pkgversion='Homebrew gcc49 4.9.2' --with-bugurl=https://github.com/Homebrew/homebrew-versions/issues --enable-plugin --disable-nls --enable-multilib
Thread model: posix
gcc version 4.9.2 (Homebrew gcc49 4.9.2) 

==============================================================================
Apple clang 6.0:

% /usr/bin/clang -v
Apple LLVM version 6.0 (clang-600.0.56) (based on LLVM 3.5svn)
Target: x86_64-apple-darwin14.0.0
Thread model: posix

==============================================================================
Apple gcc 6.0:

% /usr/bin/gcc -v
Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
Apple LLVM version 6.0 (clang-600.0.56) (based on LLVM 3.5svn)
Target: x86_64-apple-darwin14.0.0
Thread model: posix

==============================================================================

-------------- next part --------------
A non-text attachment was scrubbed...
Name: smime.p7s
Type: application/pkcs7-signature
Size: 4839 bytes
Desc: not available
URL: <http://mailman.iro.umontreal.ca/pipermail/gambit-list/attachments/20150114/ed23777c/attachment.bin>