Hi everyone,
I put up some initial build profile results on the Wiki. The top
three time sinks are: 33% C/C++ compile, 27% dmake/build.pl,
22% dependencies (dpcc). So about 50% of our time is spent
on build or build related activities. Build time on a fast 4GB
machine is 17h. More details here:
Looking at the available data the build times can probably be
decreased by a factor of 4 without source code changes. With small
source code changes the improvement could be more significant.
I'm currently doing some Jam based build tests in transex3, and
I'll tackle other parts next. Jam is a build tool written by Christopher
Seiwald and released by Perforce. They use it internally to build all
Perforce platform versions and it is used by other FOSS projects like
Boost, Freetype and Haiku. There is an old but interesting article on
transitioning from make to Jam here:
Jam works by doing a single start up pass where it reads all the build
files and stats all sources and targets. Once the dependency graph is
ready the requested number of processes is spawned in parallel.
The source code is 12k lines of C (+2k lines in a bison parser).
Another alternative would be to change the build system to use
non-recursive dmake. The effort is probably at par with rewriting the build
system from scratch in jam. The build.pl/dmake source is 39k lines of C
and Perl. My very rough estimate for the available speedup would be 1.5-3x.
In any case, IMHO the best strategy would be to roll out an improved
build without replacing the existing build.pl/dmake system. Developers
can then switch once the new build system performs measurably better.
Ideas and suggestions most welcome. :-)
Take care,
