[SunRescue] optimizing executables for SPARC

[James Lockwood]

On Sat, 4 Mar 2000, Gregory Leblanc wrote:

> I've taken to re-compiling a lot of things on my x86 linux machine to get
> the most performance out of my processor.  Things do seem to be a bit
> faster, although it doesn't always make a difference.  What I'm wondering is
> if it will make a difference to compile things with optimizations on my SS20
> (superSPARC I).  I'm running gcc, because it's free.  Any thoughts and
> pointers appreciated.

If you're doing heavy FP then recompiling with V8 optimizations can help
significantly.  Sun Workshop in general produces tighter code, but the
difference isn't pronounced unless you're running on an Ultra.  gcc -O3
with selective use of profiling and loop unrolling will do a fairly good
job.

There's no "magic bullet" set of options.  What speeds some code up will
slow other code down.  Many x86 performance optimizations for different
implementations gain speed from stricter memory alignment, this is less of
an issue (well, a different one) on Sparc as stricter alignment has always
been enforced.

-James