== Introduction ==

distcc can distribute compilations across a network, greatly reducing compile times. Even if you only have one other computer available, it can already make a noticeable difference.


== Usage instructions ==

The following instructions assume your main development machine is running Haiku and the helper machines run Linux.

=== Preparing helper machines ===

* Install [http://code.google.com/p/distcc/ distcc], using the package manager or from source

* Check out the build tools
{{{
svn co http://svn.haiku-os.org/haiku/buildtools/trunk buildtools
}}}

* Check out partial Haiku tree
{{{
svn co --depth=immediates http://svn.haiku-os.org/haiku/haiku/trunk haiku
svn update --set-depth infinity build headers/config headers/os headers/posix
}}}

* Build the cross-compilers
{{{
mkdir generated.x86gcc2
mkdir generated.x86gcc4
cd generated.x86gcc2
../configure --use-32bit --alternative-gcc-output-dir ../generated.x86gcc4 --build-cross-tools ../../buildtools/
cd ../generated.x86gcc4
../configure --use-32bit --alternative-gcc-output-dir ../generated.x86gcc2 --build-cross-tools-gcc4 x86 ../../buildtools/
cd ..
}}}

* Make the cross-compilers available under a verbose name. Run {{{gcc -v}}} to find  out the exact version. Verify that they are the same as on the Haiku machine.
{{{
mkdir bin && cd bin
ln -s ../generated.x86gcc2/cross-tools/i586-pc-haiku/bin/gcc i586-pc-haiku-gcc-2.95.3-haiku-100818
ln -s ../generated.x86gcc4/cross-tools/i586-pc-haiku/bin/gcc i586-pc-haiku-gcc-4.4.4-haiku-101111
cd ..
}}}

* Start the distcc daemon
{{{
PATH=$PWD/bin:$PATH distccd --allow <IP of Haiku machine>
}}}


=== Preparing the Haiku machine ===

* Get the Haiku distcc [http://ports-space.haiku-files.org//?directory=./&search=sys-devel/distcc binaries]. Information on the port is [http://ports.haiku-files.org/wiki/sys-devel/distcc here]

* Make GCC 2 and 4 available under the verbose names.
{{{
ln -s /boot/develop/abi/x86/gcc2/tools/current/bin/gcc /boot/common/bin/i586-pc-haiku-gcc-2.95.3-haiku-100818
ln -s /boot/develop/abi/x86/gcc4/tools/current/bin/gcc /boot/common/bin/i586-pc-haiku-gcc-4.4.4-haiku-101111
}}}

* Adjust {{{generated.x86gcc2/build/BuildConfig}}}
{{{
HAIKU_CC ?= distcc i586-pc-haiku-gcc-2.95.3-haiku-100818 ;
}}}

* Adjust {{{generated.x86gcc4/build/BuildConfig}}}
{{{
HAIKU_CC ?= distcc i586-pc-haiku-gcc-4.4.4-haiku-101111 ;
}}}

* Add hostname or IP addresses of the helpers to {{{/boot/common/etc/distcc/hosts}}}
 Optionally add {{{localhost}}}. If this machine is slower than the helpers, it might slow down the build. You can easily find out by means of a quick benchmark. Even if you don't add {{{localhost}}}, it will still be busy distributing running jam, distributing jobs and linking.

Now you can run {{{jam}}} as usual, but you should pass twice the total number of cores in the distcc network to the {{{-j}}} option. During a build, you can see what is happening by running
{{{
distccmon-text 1
}}}

If you want to use distcc in combination with with [wiki:DevelopmentTools/ColorGCC colorgcc], you can mask simply the distcc executable
{{{
cd /boot/common/bin
mv distcc distcc_real
wget http://dev.haiku-os.org/raw-attachment/wiki/DevelopmentTools/DistCC/distcc
chmod +x distcc
}}}

== References ==
* [http://ports.haiku-files.org/wiki/sys-devel/distcc/3.1/1 distcc on HaikuPorts]
* [http://www.gentoo.org/doc/en/cross-compiling-distcc.xml distcc and cross-compilers]
* [http://article.gmane.org/gmane.os.haiku.devel/8761 Using distcc (www.distcc.org) to speed up building Haiku]