If you are owner of a Pentium, an AMD K6, Athlon or Athlon-XP CPU, you might want to use compiler optimizations to compile your version of Kwave that is running some percents faster. The gain in speed will be up to 30% on some systems, whereas the functions dealing with signal manipulation and all functions that do complex time-frequency operations (like FFT and Sonagram) will profit most from it.
You do not need to understand much about programming for using an optimized compiler to compile Kwave, but maybe you will need some time to get the compiler itself working and installed.
You can easily compile the RPM package optimized for Athlon,
Athlon-XP, Pentium and Pentium Pro
(and some other CPUs) by using some defines in your
You can either modify your system's
/usr/lib/rpm or the
.rpmrc file in your home directory.
There you can specify option lines like these:
optflags: i586 -O2 -march=pentium -DNDEBUG -fomit-frame-pointer
optflags: i686 -O2 -march=pentiumpro -DNDEBUG -fomit-frame-pointer
optflags: athlon -O2 -march=athlon -DNDEBUG -fomit-frame-pointer
optflags: k6 -O3 -march=k6 -DNDEBUG -fomit-frame-pointer
optflags: k7 -O3 -march=athlon-xp -DNDEBUG -fomit-frame-pointer
(I found those nice tricks at http://www.keywarrior.net/duesti/rpmopt.en.html. Thanks to Matthias Düsterhöft!).
This means that on a
k7 architecture the
rpm package will be compiled using
-O3 -march=athlon-xp -DNDEBUG
as compiler option and so
on, you might extend or adapt these to your own needs.
The settings apply to all of the sections before in all
places where rpmbuild -ta is used or where a binary
RPM is to be created out of a source rpm using
If rpm refuses to install your package because it seems not to fit to your computer's architecture, you can normally just install an optimized package by specifying the additional parameter --ignorearch and don't care.
The invocation of the compiler is quite simple. It normally
is sufficient to set the environment variables
in the correct way and then compile as usual. For the best settings
please consult the documentation or homepage of the corresponding
If you build Kwave from a source tree (unpacked tar.bz2 or from GIT) the flags need to be specified before the call. For example:
%CFLAGS="-O4 -march=athlon-xp -mcpu=athlon-xp -pipe" \ CXXFLAGS="-O4 -march=athlon-xp -mcpu=athlon-xp -pipe" \ cmake
If you re-build Kwave from a source rpm package, please follow the instruction in the previous section.