  For the parallel-in-time integration method Parareal, pipelining can be used
to hide some of the cost of the serial correction step and improve its
efficiency. The paper introduces a basic OpenMP implementation of pipelined
Parareal and compares it to a standard MPI-based variant. Both versions yield
almost identical runtimes, but, depending on the compiler, the OpenMP variant
consumes about 7% less energy and has a significantly smaller memory footprint.
However, its higher implementation complexity might make it difficult to use in
legacy codes and in combination with spatial parallelisation.
