Setting Up

Instructions on how to install Vernier’s libraries and public header files can be found here. The lib directory contains libraries to be linked against, whereas the include directory contains any public header files (C++) or modules (Fortran) that need to be included to gain access to the API.

The -DBUILD_SHARED_LIBS CMake option is used to choose whether the libraries are built statically or dynamically.

Manually Linking to Installed Libraries

Flags of interest when compiling manually:

# C++
mpicxx foo.cpp -I/path/to/include -Wl,-rpath=/path/to/lib -L/path/to/lib -lvernier

# Fortran
mpifort bar.f90 -I/path/to/include -Wl,-rpath=/path/to/lib -L/path/to/lib -lvernier_f -lvernier_c -lvernier

It is also possible to use LD_LIBRARY_PATH instead of -Wl,-rpath=:

export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/path/to/lib

Including Vernier in a CMake Project

The CMake lines below are always a necessary starting point in order to find the Vernier package. This can be done anywhere in your project directory as long as Vernier is found before linking/using.

# The 'find_package' function needs to know where to go looking for the
# Vernier package
set(CMAKE_PREFIX_PATH /path/to/lib)

# Find Vernier
find_package(vernier CONFIG)

Note

Instead of setting CMAKE_PREFIX_PATH, you can also do…

set(vernier_DIR /path/to/lib/cmake/vernier)

(The key difference being that the full path to vernierConfig.cmake is mandatory, whereas it is sufficient to just point to the lib directory when using CMAKE_PREFIX_PATH).

The subsequent steps for linking to the Vernier libraries and adding include dependencies may look something like:

# Link Vernier libraries
target_link_libraries(foo PUBLIC
        vernier::vernier_f  # Only required for Fortran
        vernier::vernier_c  # Only required for Fortran
        vernier::vernier
        )

# Include Vernier headers
target_include_directories(foo PUBLIC
        /path/to/include
        )

Environment Variables

VERNIER_OUTPUT_FORMAT

This environment variable determines the format of the outputted tables of data. There are currently two options:

drhook: Mimics the output format of the DrHook profiling tool so that the same post-processing techniques can be used.
threads: A custom, strung-together, format where threads have their own seperate table of walltimes.

If this environment variable remains unset, then the default output format is the drhook option.

VERNIER_IO_MODE

Determines the output mode to use. Currently only supports being set to multi but single-file-output may be added in the future.

VERNIER_OUTPUT_FILENAME

Sets the output filename, which is “vernier-output” by default. Vernier will append the MPI rank onto the end of this name by default, resulting in a file called vernier-output-0 for the first MPI rank, for example.