Laurent,
> From [EMAIL PROTECTED] Wed Sep 15 20:37:35 1999
>
> Bill Rea wrote:
> >
> > This is using MacLucasUNIX compiled with the Sun workshop compilers.
>
> Which version and which flags did you use? I guess you ran
> your tests under Solaris 7, right?
The MacLucasUNIX was v 6.20. The Ultra 5 and 10 were Solaris 7, both
E450's were Solaris 2.6. I tried both workshop 4 and workshop 5
compilers. The options in the make file which gave the fastest
times on the tests were:-
OPT=-fast -xO4 -xtarget=ultra -xarch=v8plusa -xsafe=mem -xdepend \
-xparallel -xchip=ultra
> That's very strange! I have benchmarked some code using both
> flags (with -fast preprended) under Solaris 7 (which is required
> to run code compiled with -xarch=v9) and v9 helped; however the
> code was purely 64-bit integer.
>
> There's also a very interesting flag to test that's not
> documented in Sun cc doc: -xinline=all. I used it by error but
> it did a great job with the code I was working on.
I'll try this option and also put the -xarch=v9 to a test on a
new exponent when the next one finishes. The implication in the
WS4 documentation is that the -xinline=all is automatically used
with -xO4, but it's worth trying anyway.
> I don't know the tests supplied but the difference might result
> from the way time is counted. I think the best way to check the
> speed of a code is to use getrusage for the process only
> (RUSAGE_SELF) and to only take into account the user time. This
> way I get very consistent timings for the before mentioned code
> (BTW, the code is ecdl by Robert Harley, used to crack ECC).
The time reports clock time, user time, and system time. I was
comparing user time. I talked very briefly to a Sun Engineer and he
said it probably had more to do with keeping the processor fed.
Sometimes optimizations in the code don't translate into faster speeds
because the limiting factor is memory access times. The CPUs with
bigger caches perform better than you would expect given their clock
speeds. However, he was just as surprized as I was that the v9 option
didn't produce faster code.
Bill Rea, Information Technology Services, University of Canterbury \_
E-Mail b dot rea at its dot canterbury dot ac dot nz </ New
Phone 64-3-364-2331, Fax 64-3-364-2332 /) Zealand
Unix Systems Administrator (/'
_________________________________________________________________
Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm
Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
