AMD-64 optimizations, some (new) code
saghmos at xter.net
Tue Sep 27 20:04:00 CEST 2005
Torbjorn Granlund wrote:
> I suppose that's true for any programming project, but since GMP
> is a volunteer project, I cannot just speed up development.
Obviously. I assumed you had partially ported/optimized code that could
be released sooner. This might still be true, but you might have other
> But I don't agree that the main value of GMP 5 would be AMD64
> assembly code. Most of the speedups will come from C code
No, I meant that unless the new C code is ALSO optimized (for the many
different platforms that is used) the new algorithms will probably not
provide that much improvement over the old, but well optimized, version
thus making the new C code less interesting. Of course I assume the
current algorithms are near optimal, with good assembly routines that
provide in some cases many times the speed of the same algorithm in C.
In these cases, a very well optimized assembly code with worse algorithm
will probably provide equal or better performance than the new and
better algorithm in C.
Meanwhile, we don't have AMD64 optimized code, forget about any new
algorithm/improvemtns; We don't have the basic perfomance expected from
a truly giant workhorse. I think in this case, at least some, will value
basic assembly code with 2-3x improvement over the current C code TODAY,
than new Algorithms/C-code next year. Thus, I think during this time,
most will eventually type their own assembly or port the existing ones,
thus making your (and other volunteer's) effort of much less value,
which is very sad and wastful.
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