XL Fortran Enterprise Edition for AIX : User's Guide - IBM

-qtune Option
Syntax
-qtune=implementation
Tunes instruction selection, scheduling, and other implementation-dependent
performance enhancements for a specific implementation of a hardware
architecture. The compiler will use a -qtune setting that is compatible with the
target architecture, which is controlled by the -qarch, -q32, and -q64 options.
If you want your program to run on more than one architecture, but to be tuned to
a particular architecture, you can use a combination of the -qarch and -qtune
options. These options are primarily of benefit for floating-point intensive
programs.
By arranging (scheduling) the generated machine instructions to take maximum
advantage of hardware features such as cache size and pipelining, -qtune can
improve performance. It only has an effect when used in combination with options
that enable optimization.
Although changing the -qtune setting may affect the performance of the resulting
executable, it has no effect on whether the executable can be executed correctly on
a particular hardware platform.
Arguments
auto
pwr
pwr2
pwr2s
p2sc
Automatically detects the specific processor type of the compiling
machine. It assumes that the execution environment will be the
same as the compilation environment.
The optimizations are tuned for the POWER processors.
The optimizations are tuned for the POWER2 processors.
pwrx is a synonym for pwr2, but pwr2 is preferred.
The optimizations are tuned for the desktop implementation of the
POWER2 architecture, which has a narrower processor-to-memory
bus than other POWER2 implementations. Quad-word instructions,
which are slower on these machines than on other POWER2
machines, are deemphasized to reduce bus contention. That is,
there may be fewer of them or none at all.
The optimizations are tuned for the POWER2 Super Chip.
601 The optimizations are tuned for the PowerPC 601 processor.
603 The optimizations are tuned for the PowerPC 603 processor.
604 The optimizations are tuned for the PowerPC 604 processor.
rs64a
rs64b
rs64c
pwr3
pwr4
pwr5
ppc970
The optimizations are tuned for the RS64I processor.
The optimizations are tuned for the RS64II processor.
The optimizations are tuned for the RS64III processor.
The optimizations are tuned for the POWER3 processors.
The optimizations are tuned for the POWER4 processors.
The optimizations are tuned for the POWER5 processors.
The optimizations are tuned for the PowerPC 970 processors.
XL Fortran Compiler-Option Reference 251