[egit-dev] jgit-timestamp-provider performance

[Michael Keppler <Michael.Keppler@xxxxxx>]

Hi friends,

I recently profiled a huge maven build in our company and noticed that 
the jgit-timestamp-provider used in tycho often takes between 3 and 7 
seconds per module on our fast build servers. For small modules that can 
sometimes be the majority of the build time and sum up to several 
minutes in an aggregator! The time is spent in revwalk.next(), as to be 
expected.

Does anyone of you see some potential for optimization of the revwalk, 
e.g. by means of additional filters or similar? Code can be seen at 
https://github.com/eclipse/tycho.extras/blob/master/tycho-buildtimestamp-jgit/src/main/java/org/eclipse/tycho/extras/buildtimestamp/jgit/JGitBuildTimestampProvider.java#L166

If not, is there anything I can do outside of tycho? E.g. might checking 
out a shallow copy only or garbage collecting the repository before the 
build make a difference for that kind of revwalk?

Ciao, Michael