New long compile times for grid_tools.cc?

[bangerth]

I suspect that this is new and must have happened over the past 3 or so weeks while I was mostly off work -- though I'm not sure it's actually new and/or unexpected. Anyway, now that I'm back, I'm seeing that grid_tools.cc takes quite a long time to compile, and I see that the .s (assembler) file has 262 MB and the .o` file has 78 MB:

1/build> ps aux | grep 25150
bangerth  25150  100  0.4 1394340 1277472 pts/4 R    19:56   4:17 as -I /home/fac/g/bangerth/p/deal.II/1/build/source/grid -I /home/fac/g/bangerth/p/deal.II/1/dealii/source/grid -I /home/fac/g/bangerth/p/deal.II/1/build/include -I /home/fac/g/bangerth/p/deal.II/1/dealii/include --64 --compress-debug-sections -o source/grid/CMakeFiles/object_grid_debug.dir/grid_tools.cc.o /tmp/cc9lEB7V.s
bangerth  25254  0.0  0.0 112816   976 pts/4    S+   20:01   0:00 grep --colour=auto 25150
1/build> ll /tmp/cc9lEB7V.s
-rw------- 1 bangerth fac 261269881 Aug 22 19:56 /tmp/cc9lEB7V.s
ll source/grid/CMakeFiles/object_grid_debug.dir/grid_tools.cc.o
-rw-r--r-- 1 bangerth fac 78254432 Aug 22 20:01 source/grid/CMakeFiles/object_grid_debug.dir/grid_tools.cc.o

I took the assembler ~4 minutes to work through this.

This isn't the only large file, though:

1/build> ls -lS `find source/ -name *.cc.o` | head -30
-rw-r--r-- 1 bangerth fac 78254432 Aug 22 20:01 source/grid/CMakeFiles/object_grid_debug.dir/grid_tools.cc.o
-rw-r--r-- 1 bangerth fac 72860152 Aug 22 19:57 source/numerics/CMakeFiles/object_numerics_debug.dir/matrix_creator_inst3.cc.o
-rw-r--r-- 1 bangerth fac 72130456 Mar 30 20:11 source/numerics/CMakeFiles/obj_numerics_debug.dir/matrix_creator_inst3.cc.o
-rw-r--r-- 1 bangerth fac 63118000 Mar 30 20:13 source/fe/CMakeFiles/obj_fe_debug.dir/fe_tools_extrapolate.cc.o
-rw-r--r-- 1 bangerth fac 58652312 Mar 30 20:12 source/grid/CMakeFiles/obj_grid_debug.dir/grid_tools.cc.o
-rw-r--r-- 1 bangerth fac 58163680 Aug 22 19:58 source/multigrid/CMakeFiles/object_multigrid_debug.dir/mg_transfer_global_coarsening.cc.o
-rw-r--r-- 1 bangerth fac 54446768 Aug 22 19:57 source/fe/CMakeFiles/object_fe_debug.dir/fe_tools_extrapolate.cc.o
-rw-r--r-- 1 bangerth fac 53013144 Aug 22 19:56 source/fe/CMakeFiles/object_fe_debug.dir/fe_values_views.cc.o
-rw-r--r-- 1 bangerth fac 49933976 Aug 22 19:56 source/numerics/CMakeFiles/object_numerics_debug.dir/matrix_creator_inst2.cc.o
-rw-r--r-- 1 bangerth fac 49429128 Mar 30 20:09 source/numerics/CMakeFiles/obj_numerics_debug.dir/matrix_creator_inst2.cc.o
-rw-r--r-- 1 bangerth fac 40566224 Aug 22 19:57 source/grid/CMakeFiles/object_grid_debug.dir/tria.cc.o
-rw-r--r-- 1 bangerth fac 38648568 Mar 30 20:11 source/matrix_free/CMakeFiles/obj_matrix_free_debug.dir/matrix_free.cc.o
-rw-r--r-- 1 bangerth fac 38557416 Aug 22 19:56 source/matrix_free/CMakeFiles/object_matrix_free_debug.dir/matrix_free.cc.o
-rw-r--r-- 1 bangerth fac 37968928 Mar 30 20:09 source/numerics/CMakeFiles/obj_numerics_debug.dir/derivative_approximation.cc.o
-rw-r--r-- 1 bangerth fac 35582504 Jun 28 09:57 source/fe/CMakeFiles/object_fe_debug.dir/fe_values_inst3.cc.o
-rw-r--r-- 1 bangerth fac 35283192 Mar 30 20:09 source/fe/CMakeFiles/obj_fe_debug.dir/fe_values_inst3.cc.o
-rw-r--r-- 1 bangerth fac 35268376 Mar 30 20:08 source/numerics/CMakeFiles/obj_numerics_debug.dir/error_estimator.cc.o
-rw-r--r-- 1 bangerth fac 34632256 Aug 22 19:56 source/numerics/CMakeFiles/object_numerics_debug.dir/vector_tools_project.cc.o
-rw-r--r-- 1 bangerth fac 34526368 Mar 30 20:08 source/numerics/CMakeFiles/obj_numerics_debug.dir/error_estimator_inst2.cc.o
-rw-r--r-- 1 bangerth fac 34356096 Aug 22 19:56 source/numerics/CMakeFiles/object_numerics_debug.dir/derivative_approximation.cc.o
-rw-r--r-- 1 bangerth fac 34068792 Mar 30 20:11 source/grid/CMakeFiles/obj_grid_debug.dir/tria.cc.o
-rw-r--r-- 1 bangerth fac 33845664 Mar 30 20:09 source/numerics/CMakeFiles/obj_numerics_debug.dir/vector_tools_project.cc.o
-rw-r--r-- 1 bangerth fac 33289328 Jun 28 09:57 source/fe/CMakeFiles/object_fe_debug.dir/fe_values_inst6.cc.o
-rw-r--r-- 1 bangerth fac 32994872 Mar 30 20:09 source/fe/CMakeFiles/obj_fe_debug.dir/fe_values_inst6.cc.o
-rw-r--r-- 1 bangerth fac 32463880 Mar 30 20:09 source/fe/CMakeFiles/obj_fe_debug.dir/mapping_fe_field.cc.o
-rw-r--r-- 1 bangerth fac 31425744 Mar 30 20:08 source/fe/CMakeFiles/obj_fe_debug.dir/mapping_fe_field_inst2.cc.o
-rw-r--r-- 1 bangerth fac 29104184 Aug 22 19:56 source/fe/CMakeFiles/object_fe_debug.dir/mapping_fe_field.cc.o
-rw-r--r-- 1 bangerth fac 28444576 Mar 30 20:09 source/dofs/CMakeFiles/obj_dofs_debug.dir/dof_accessor_set.cc.o
-rw-r--r-- 1 bangerth fac 28068760 Aug 22 19:56 source/fe/CMakeFiles/object_fe_debug.dir/mapping_fe_field_inst2.cc.o
-rw-r--r-- 1 bangerth fac 27590128 Aug 22 19:56 source/matrix_free/CMakeFiles/object_matrix_free_debug.dir/evaluation_template_factory_inst5.cc.o

Is this all expected?

[drwells]

I didn't check the sizes of the object files but grid tools takes about 4 minutes for me to compile in release mode both on master and v9.5.1. I've known for a while that this is one of the more expensive files - see also #13949 (comment). In particular we should split up GridTools the same way we split up VectorTools.

[bangerth]

OK, let's close this then if this isn't something that's new.