Parallel Programming Guide for HP-UX Systems

UPC
Tuning
Chapter 5 105
Tuning
-tune option [Tru64 UNIX Only]
Note that -tune ev[x] does not imply -arch ev[x]. Unlike -arch, -tune does not cause
instruction emulation or illegal instructions on any Alpha architecture.
A program compiled with any of the options runs on any Alpha processor. Beginning with
Version 4.0 of the operating system and continuing with subsequent versions, the operating
system kernel includes an instruction emulator. This capability allows any Alpha chip to
execute and produce correct results from Alpha instructions, even if some of the instructions
are not implemented on the chip. Applications using emulated instructions run correctly, but
can incur significant emulation overhead at run time.
On Tru64 UNIX, the psrinfo -v command can be used to determine which type of processor
is installed on any given Alpha system.
Select processor-specific instruction tuning for implementations of the operating system
architecture. Using the -tune option causes the generated code to run correctly on all
implementations of the architecture. Tuning for a specific implementation may improve
run-time performance; however, code tuned for a specific target may run slower on another
target.