When to use the XCode Distributed Build Feature

Question

I work in a small iPhone development team, in our office, we have at least 4 copies of XCode running on the network at any one time. Contemplating getting everyone to have it running.

We're networked together using a standard WIFI Switch, so network speed and latency isn't as good as wired network...

Just wondering, is there any real time gain to be had on using distributed builds? Once it passes the relevant data back and forth over the network. At least for relatively small projects.

Answer 1

it depends on your project, its dependencies, and the amount of data that must be transferred.

15-20 seconds is not terrible. certainly, there is more work overall to be done. it may be a good idea for everyone to farm it out to a very fast Mac Pro, rather than to each other if you're using dual cores (that info was not given).

as far as project configuration: if you have a bunch of dependent libraries in your projects, then it may help to disable precompiled headers. much of the equation is the average number of dependencies, and the number of objects to generate.

at 15-20 seconds, it would help many developers to write so they optimize their build times before farming out. if it were a few minutes, then you may want to jump straight into distributed builds with a 8 or 12 core.

one easily overlooked aspect of slow builds on small projects: disable static analysis per build, and just run it manually every hour two, fixing every issue then.

otherwise, your project could probably be divided into smaller projects/libraries. chances are, you won't always be editing the same dependencies.

assuming compilation, linking, etc are where the time is spent at this point: much of the rest falls into the typical issues involved with building c and c++ programs. minimize your dependencies and include graphs. it's actually quite easy to accomplish with objc; since much of the interfaces use objc-types, you can use forwards.

if your library is small (e.g. less than 50 objects generated), then you may also gain a speedup by not using precompiled headers. if everything already depends on your inclusion of 12 system frameworks included by the pch.... then try it in the next project.

of course, you could just try timing a clean rebuild, a build with generated pch files, and several incremental builds in order to come to a conclusion.