GeoModelKernel: Compile GeoXF.cxx with optimization, even in debug builds.

GeoXF.cxx makes heavy use of Eigen. In debug builds it ends up being much, much slower than in optimized builds, to the point where where it makes it difficult to run things in dbg. Tweak the build so that we compile GeoXF.cxx with optimization, even in dbg builds. We also need to use the flatten attribute on the functions that use Eigen, so ensure that the Eigen operations are completely inlined.

This was motivated by the fact that numerous tests are timing out in the dbg build. This change alone reduced the time required by one test from ~600s to ~400s.

Thanks, @ssnyder , for this update!

Since they are the authors of that part, I let @boudreau and @tsulaia take a look and comment further on these changes.

Best, -- Ric.

mentioned in commit 67c36f3e

merged

Scott, I just merged as you can see.

I was wondering which optimization level is used during the debug build? The reason I ask is normally my builds of Eigen packages are faster in debug mode.. but maybe that is because I also use -O0 which switches off the massive inlining.

Hi @rbianchi , given this has already been merged, could you please open a new MR on atlasexternals so that Athena will see this change next time the externals get updated?

Also tagging @akraszna for info

hi Joe -

Debug builds should use -O0.

This isn't to address issues with build time, but rather run time with the debug builds.

Aha, I misread the original comment. This make much more sense! Yes, eigen without optimization is extremely slow.