Only 70% of theoretical peak performance on FreeBSD 8/amd64, Corei7 920

[Andriy Gapon]

on 13/04/2010 02:33 Maho NAKATA said the following:
> From: Andriy Gapon <avg at freebsd.org>
>> Another question is what compilers (what versions of GCC) were used on both
>> system to compile the program?
> 
> Hi
> 
> on Ubuntu $ gcc -v Using built-in specs. Target: x86_64-linux-gnu Configured
> with: ../src/configure -v --with-pkgversion='Ubuntu 4.4.1-4ubuntu9'
> --with-bugurl=file:///usr/share/doc/gcc-4.4/README.Bugs
> --enable-languages=c,c++,fortran,objc,obj-c++ --prefix=/usr --enable-shared
> --enable-multiarch --enable-linker-build-id --with-system-zlib
> --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
> --with-gxx-include-dir=/usr/include/c++/4.4 --program-suffix=-4.4
> --enable-nls --enable-clocale=gnu --enable-libstdcxx-debug --enable-objc-gc
> --disable-werror --with-arch-32=i486 --with-tune=generic
> --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu
> --target=x86_64-linux-gnu Thread model: posix gcc version 4.4.1 (Ubuntu
> 4.4.1-4ubuntu9)
> 
> on FreeBSD % gcc44 -v Using built-in specs. Target: x86_64-portbld-freebsd8.0
>  Configured with: ./../gcc-4.4-20100330/configure --disable-nls
> --libdir=/usr/local/lib/gcc44 --libexecdir=/usr/local/libexec/gcc44
> --program-suffix=44 --with-as=/usr/local/bin/as --with-gmp=/usr/local
> --with-gxx-include-dir=/usr/local/lib/gcc44/include/c++/
> --with-ld=/usr/local/bin/ld --with-libiconv-prefix=/usr/local
> --with-system-zlib --disable-libgcj --prefix=/usr/local
> --mandir=/usr/local/man --infodir=/usr/local/info/gcc44
> --build=x86_64-portbld-freebsd8.0 Thread model: posix gcc version 4.4.4
> 20100330 (prerelease) (GCC)

Is this what was used to compile the code in hot path (the code that performs
all the actual calculations)?  The answer is not obvious.
GCC 4.4 is known to produce better code for modern CPUs, partially because it
has knowledge of recently introduced instructions.

-- 
Andriy Gapon