The Secret to Fast, Reliable Builds - Part 1

Parallel execution is a popular technique for reducing software build length, and for good reason. These days, multi-core computers have become standard — even my laptop has four cores — so there’s horsepower to spare. And it’s “falling over easy” to implement: just slap a “-j” onto your make command-line, sit back and enjoy the benefits of a build that’s 2, 3 or 4 times faster than it used to be. Sounds great!
But then, inevitably, invariably, you run into parallel build problems: incomplete dependencies in your makefiles, tools that don’t adequately uniquify their temp file names, and any of a host of other things that introduce race conditions into your parallel build. Sometimes everything works great, and you get a nice, fast, correct build. Other times, your build blows up in spectacular fashion. And then there are the builds that appear to succeed, but in fact generate bogus outputs, because some command ran too early and used files generated in a previous instead of the current build.
To read the rest of this article, check out Eric Melski's blog here .