[llvm-dev] [LNT][RFC] Providing useful Order context in LNT

[Chris Matthews via llvm-dev]

I’d like some feedback on how people are using Orders in LNT, and how we can improve that.  Abstractly, Orders are the version of the thing LNT is testing. On llvm.org/perf, Orders are the SVN revision of the compiler.  The Order is used to combine runs together, as well as to provide the x-axis of LNT’s graphs. Other things I have seen used as Orders: git tags, git distance, unix time stamps, letters or numbers.

What I would really like in LNT is more information about Orders.  Data I (personally) would like:
 - blame list
 - change list with commit messages
 - links to more information

It would be great to be able to show change lists between Orders so we know what the Order is actually capturing, including in the performance graphs and run pages.  For SVN based system, that is easy, it is the change list between the two revisions. I’d also like to be able to link to more information (like veiwvc in the case of SVN), I think that can be accomplished with templates URLs.  Long term, it would be nice to formally blame performance regressions, so a real blame list is needed for that.

I think the ideal interface for everything I have been thinking about is just given two Orders, show the changes.  Concretely for the SVN case I think we’d need to have LNT keep a mirror of the SVN repo of interest.  That might be too much to formally reside in LNT, so maybe a new external service that collects and caches Order information.  Does anyone have any input on what and how we should do this?