I've discovered an option that caused 2019.2 to use all of the cores
correctly.
Use "-pin on" and it works as expected, using all 12 cores, CPU load being
show as appropriate (gets up to 68% total CPU utilisation)
Use "-pin auto", which is the default, or "-pin off" and it will only use a
single
gmx 2019.2 compiled using threads only uses a single core mdrun_mpi
compiled using MPI only uses a single core, gmx 2016.3 using threads
uses all 12 cores.
For compiling thread version of 2019.2 used:
cmake .. -DGMX_GPU=ON -DCMAKE_INSTALL_PREFIX=/usr/local/gromacs/gromacs-2019.2
For compiling
