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?
> (1) If I used the -xarch=v9
> option on those systems that support this option, the resulting
> binary runs slower on the tests than using -xarch=v8plusa.
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.
> (2) Differences in speeds on the tests supplied with the software
> don't translate into differences in speed when working on Mersenne
> numbers of the size above. Even with speed differences around 10%
> on the tests showed no discernable differences in practice.
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).
Laurent
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