Distributed compilation with distcc

Distributed compilation in Source Mage allows a cast to spread the load of a build over several computers. This can greatly increase the speed of casting spells.

Requirements

distcc and GCC must be installed on involved computers
the GCC versions and build targets must be compatible, this means a GCC installation targeting sparc can't be used in a network of x86 computers and a GCC version of 2.95.3 can't be used together with 3.1
computers which act as volunteers must run the distcc daemon. In Source Mage this is most easily done by selecting y when asked whether distcc should be invoked via xinetd (cast xinetd to install it on SMGL system)

Usage

On the computer which should use distributed compilation run sorcery command and go to the Parallel/Cached/Distributed Compiling menu under Option, enter the network hostnames or IP-addresses of the volunteers in the DISTCC_HOSTS text field. Don't forget to add localhost if you want it to help.

Try casting a spell now and hopefully the compilation will be spread among the volunteers you specified.

Warning: only enable distributed compilation on a trusted network – no access control is done.

Cross compilation with distcc

A cross compiler for the desired target architecture (we will assume it's for an x86-64 on an x86 machine and located under /opt/x86_64-unknown-linux-gnu.
Have "distcc" spell installed and working either using the init script or the xinetd to run distcc.

For more info on cross compilers see http://www.kegel.com/crosstool/.

Steps on the client

1. Set up a "masquerade directory":

# mkdir /usr/lib/distcc/bin
# cd /usr/lib/distcc/bin
# ln -s ../../../bin/distcc gcc
# ln -s ../../../bin/distcc cc
# ln -s ../../../bin/distcc g++
# ln -s ../../../bin/distcc c++

2. Add the "masquerade directory" infront of your PATH variable:

for temporary testing: export PATH="/usr/lib/distcc/bin:$PATH"
for more permanent change add the command above to your ~/.bash_profile file

This doesn't hurt normal compiling, just don't dispel distcc without removing this from your path.

Steps on the server

1. Create a user for distcc to run as:

# useradd distcc

2. Make sure your cross tools bin directory has a gcc, cc, g++ and c++ symlinks to the appropriate binaries:

# cd /opt/x86_64-unknown-linux-gnu/bin
# ln -s x86_64-unknown-linux-gnu-gcc gcc
# ln -s x86_64-unknown-linux-gnu-gcc cc
# ln -s x86_64-unknown-linux-gnu-g++ c++
# ln -s x86_64-unknown-linux-gnu-g++ g++

There isn't any need to link the ld, ar, cpp or as distcc is a distributed compilation tool not a distributed linker, C preprocessor, assembler or archiver ;-)

3. Modify the /etc/sysconfig/distcc or /etc/xinetd.d/distccd scripts appropriately to make distccd run as the distcc user:

xinetd: user = distcc
init.d: USER="distcc"

4. Give the user the appropriate path:

Make sure the /etc/passwd has the users shell as /bin/sh:

# su distcc
$ cd
$ cp /etc/skel/.bash_profile ./
$ vim .bash_profile

and add export DISTCCD_PATH="/opt/x86_64-unknown-linux-gnu/bin:$PATH" to the file after the PATH variable is set.

5. Restart your distcc server:

init.d: telinit run distcc restart
xinetd: telinit run xinetd restart

Distributed compilation

Information