Re: [bug #40225] Deterministic output ordering

[Josh Triplett]

On Thu, Oct 10, 2013 at 08:12:51AM -0400, Paul Smith wrote:
> But I understood that the impetus for this feature would be to compare
> builds between two completely different workspaces.  It doesn't seem
> very useful (to me) to ensure the order of two builds within the same
> workspace since unless it's a clean build the output will be different.

A clean build is exactly the use case.

Right now:

make clean ; make > before.log 2>&1
# change something
make clean ; make > after.log 2>&1
diff -u before.log after.log

That takes an excessively long time, because the build has to run
sequentially.

With deterministic ordering:

make clean ; make --deterministic-ordering -j$(ncpus) > before.log 2>&1
# change something
make clean ; make --deterministic-ordering -j$(ncpus) > after.log 2>&1
diff -u before.log after.log

- Josh Triplett