====== Distcc ======

===== Overview =====
Distcc is used to compile packages faster on slow machines, such as [[Santo]] or the virtual machines, by doing some of the grunt work on physical hosts.

===== Build Hosts =====
  * build0.sihnon.net ([[River]])
  * build1.sihnon.net ([[Badger]])
  * <s>build2.sihnon.net ([[Hex]])</s> //todo//

The build hosts use the following architectures:

{| class="wikitable" cellspacing="10"
|+ Architecture details
|- 
! Name
! Value
|-
| **CHOST**
| x86_64-pc-linux-gnu
|-
| **gcc version**
| 4.4.2
|}

The following cross-compilation environments are also available:
  * i586-pc-linux-gnu
  * i686-pc-linux-gnu

===== Configuring a build host =====
  * Install {{Package|direct=yes|sys-devel/distcc}} {{USEFlag|{{EnableFlag|avahi}}}}, and {{Package|direct=yes|sys-devel/crossdev}}
  * Configure the distcc daemon to accept connections from local machines only
{{File|/etc/conf.d/distccd|<source lang="text">

</source>}}

==== Configuring a new cross-compilation environment ====
Run the following command on each build host, where <tt>i586</tt> is the name of the new environment.

{{Root|<source lang="bash">
crossdev -t i586
</source>}}

This command will build the necessary tools for cross-compilation, and will take a considerable time to run. To serve as a progress check, the following stages are run:
  * binutils
  * linux-headers-quick
  * glibc-headers
  * gcc-stage1
  * linux-headers
  * glibc
  * gcc-stage2

===== Configuring a build client =====
If the client has the same CHOST as all the build hosts, then setting up distcc is straightforward:

  * Install {{Package|direct=yes|sys-devel/distcc}} {{USEFlag|{{EnableFlag|avahi}}}}
  * Configure distcc to use each of the available build hosts with the following command:
{{Root|<source lang="bash">
distcc-config --set-hosts "build0.sihnon.net build1.sihnon.net build2.sihnon.net"
</source>}}
  * Configure portage to use distcc for compilations by adding setting the following option:
{{File|/etc/make.conf|<source lang="bash">
FEATURES="distcc"
</source>}}

==== Configuring a build client with a different CHOST to the build hosts ====
As explained in the Gentoo documentation, set up a wrapper script to have distcc tell the build host which environment to use for compilation.

  * Create the wrapper script in <tt>/usr/lib/distcc/bin/</tt>, with the name of the CHOST to be used, for example, <tt>i686-pc-linux-gnu-wrapper</tt>, containing the following:
{{File|/usr/lib/distcc/bin/i686-pc-linux-gnu-wrapper|<source lang="bash">
#!/bin/bash
exec /usr/lib/distcc/bin/sparc-unknown-linux-gnu-g${0:$[[-2]]} "$@"
</source>}}

  * Make the wrapper script executable, and replace the unqualified tool symlinks with symlinks to the new wrapper:
{{Root|<source lang="bash">
cd /usr/lib/distcc/bin
chmod a+x i686-pc-linux-gnu-wrapper
rm cc gcc c++ g++
ln -s i686-pc-linux-gnu-wrapper cc
ln -s i686-pc-linux-gnu-wrapper gcc
ln -s i686-pc-linux-gnu-wrapper c++
ln -s i686-pc-linux-gnu-wrapper g++
</source>}}

===== See Also =====
  * http://www.gentoo.org/doc/en/distcc.xml
  * http://www.gentoo.org/doc/en/cross-compiling-distcc.xml