Replace tbb with std containers

[ianna]

BEGINRELEASENOTES

• SpecParRegistry: remove need for TBB

  • TBB has a slight overhead compare to std containers
  • Using std containers allows to return references to the containers in the registry

• Reverse the plan to process XML files in parallel

ENDRELEASENOTES

[ianna]

@MarkusFrankATcernch - CMS XML description would need quite a bit of work to make it modular.

[andresailer]

That means also dropping the TBB requirements for these source files, right?

[ianna]

That means also dropping the TBB requirements for these source files, right?

Please, do :-)

[ianna]

Hmm...

217 - t_LHeD_DDG4_LHeDACLick_as_ACLick_LONGTEST (Child aborted)

[MarkusFrankATcernch]

217 - t_LHeD_DDG4_LHeDACLick_as_ACLick_LONGTEST (Child aborted)

This failing test is strange. It is entirely unrelated to tbb.

[ianna]

@MarkusFrankATcernch - sorry I missed the meeting where I was planning to bring this up for discussion. Would it be possible to integrate this asap? Thanks!

[MarkusFrankATcernch]

@ianna For the time being your are the only customer of this feature. I do not see any point of not merging.
Have you removed the TBB requirements for these source files ?

[ianna]

@ianna For the time being your are the only customer of this feature. I do not see any point of not merging.
Have you removed the TBB requirements for these source files ?

no, I have not. I'm not sure I can test this change since I'm using scram and pkgtools to build it...

[andresailer]

You just need

diff --git a/DDCore/CMakeLists.txt b/DDCore/CMakeLists.txt
index 6a4f9b73..a3ded85e 100644
--- a/DDCore/CMakeLists.txt
+++ b/DDCore/CMakeLists.txt
@@ -15,7 +15,7 @@ dd4hep_print("|++> Will be Building DDCore")

 file(GLOB DDCore_SOURCES src/*.cpp src/segmentations/*.cpp src/XML/*.cpp)

-if(NOT DD4HEP_USE_TBB OR ${CMAKE_CXX_STANDARD} LESS 17)
+if(${CMAKE_CXX_STANDARD} LESS 17)
   list(APPEND EXCLUDE_HEADER include/DD4hep/SpecParRegistry.h)
   list(APPEND EXCLUDE_HEADER include/DD4hep/Filter.h)
   list(FILTER DDCore_SOURCES EXCLUDE REGEX Filter\.cpp|SpecParRegistry\.cpp )

And set DD4HEP_USE_TBB=OFF in the CMS build config

[ianna]

@andresailer - thanks! I'll update the PR.