Add the REQUIRED flag to the find_package command to find the Google
benchmark package. Without that flag, the find_package command will
happily pass if the benchmarks are not found.
However, if benchmarks is not found, then the CMake configure will then
fail because the benchmark::benchmark library is not defined. That is a
confusing error to get. Since benchmark is not a typical thing installed
on a system, this can be problematic.
Consumers of VTK-m when enabling of dropping of unused functions
will see VTK-m functions dropped. Previously this didn't happen
as VTK-m didn't build object files with the correct flags for this.
By allowing the linker to remove unused symbols we see a significant
saving the file size of VTK-m tests, examples, and benchmarks.
An OpenMP build of the tests and benchmarks goes from 168MB to
141MB which is roughly a 16% filesize reduction.
Initially I had presumed that these changes would increase link times.
But in measurements the total wall time for compilation of VTK-m has
stayed about the same ( seeing a decrease of 1.5% ). Presumably the
increased computation is offset by the reduction in file writing.
VTK-m has been updated to replace old per device benchmark executables with a device
dependent shared library so that it's able to accept a device adapter at runtime through
the "--device=" argument.
This is a library that contains parts of worklets that can be
precompiled into a library.
Currently, this library contains the implementation of ScatterCounting.
