  We present efforts at improving the performance of FLASH, a multi-scale,
multi-physics simulation code principally for astrophysical applications, by
using huge pages on Ookami, an HPE Apollo 80 A64FX platform. FLASH is written
principally in modern Fortran and makes use of the PARAMESH library to manage a
block-structured adaptive mesh. We explored options for enabling the use of
huge pages with several compilers, but we were only able to successfully use
huge pages when compiling with the Fujitsu compiler. The use of huge pages
substantially reduced the number of translation lookaside buffer misses, but
overall performance gains were marginal.
