/sys$common/syshlp/helplib.hlb FORTRAN, Logical Names, FOR$STALL_WAIT  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  If defined during execution of a parallel processing application,
  this logical name specifies the number of spin-wait cycles (see
  FOR$SPIN_WAIT) that a parallel worker subprocess should execute
  while waiting for more work to do before becoming inactive.  A
  value of 0 prevents the process from becoming inactive.  The
  default is 10 times the number of worker subprocesses.  For more
  information, see the Compaq Fortran Performance Guide.