This chapter describes how to use different features
of the HP Fortran 90 to tune your program for
optimum performance. The most important of these features is the
optimizer. You invoke the optimizer when compiling your program
by specifying either +On
(where n represents the level of optimization
to be applied to your program) or the -O
option for the default level of optimization (level 2). The -O
option is provided for compatibility with the POSIX standard and
has the same functionality as the +O2
option.
The following command line compiles prog.f90,
using the default level of optimization:
For most applications, -O
provides effective optimization. However, some applications can
realize significant increases in performance at higher levels of
optimization or when you use other features of the optimizer to
boost performance. This chapter discusses these features as well
as the following topics:
For information about getting the best performance from floating-point
intensive applications running on HP-UX, see the HP-UX
Floating-Point Guide.
Printable version
