Support parallel builds

[kvrigor]

TSMP2 should properly support CMAKE_BUILD_PARALLEL_LEVEL. Enabling this triggers build on all component models simultaneously, but this is not desirable because build logs become unreadable and diagnosing build errors becomes extremely difficult. CMAKE_BUILD_PARALLEL_LEVEL should keep the component model build sequence and let the parallelization happen at the component model level.

[mvhulten]

Or we split up the logging of the compilations of the different components (to different files).

[mvhulten]

Parallel building cannot be enabled in eCLM in the same was as for ICON and CLM3.5, because BUILD_COMMAND in cmake/BuildeCLM.cmake is (must be) empty.

[kvrigor]

because BUILD_COMMAND in cmake/BuildeCLM.cmake is (must be) empty.

Good catch--this is something that needs to be fixed in the eCLM side.

[mvhulten]

TSMP2 should properly support CMAKE_BUILD_PARALLEL_LEVEL. Enabling this triggers build on all component models simultaneously, but this is not desirable because build logs become unreadable and diagnosing build errors becomes extremely difficult. CMAKE_BUILD_PARALLEL_LEVEL should keep the component model build sequence and let the parallelization happen at the component model level.

Do you mean that you wished that setting CMAKE_BUILD_PARALLEL_LEVEL would keep the component model build sequence, but that it, in fact, does not? Then we should not use this CMake variable.

I think the word "should" is ambiguous/overloaded.

[kvrigor]

I do think to "overload" CMAKE_BUILD_PARALLEL_LEVEL (pun intended) with the parallelism required by the TSMP2 build. The default behavior of CMAKE_BUILD_PARALLEL_LEVEL is correct by design and doesn't care about the TSMP2 parallel build constraint, i.e., to keep the component model build sequence. Only us TSMP2 developers care about this constraint, and thus the onus is on us to override the default CMAKE_BUILD_PARALLEL_LEVEL behavior. That's what I mean by TSMP2 should properly support CMAKE_BUILD_PARALLEL_LEVEL.