PARALLEL COMPILATION OF CMS SOFTWARE

LHC experiments have large amounts of software to build. CMS has studied ways to shorten project build times using parallel and distributed builds as well as improved ways to decide what to rebuild. We have experimented with making idle desktop and server machines easily available as a virtual build cluster using distcc and zeroconf. We have also tested variations of ccache and more traditional make dependency analysis. We report on our test results, with analysis of the factors that most improve or limit build performance.