[kaffe] Removed GMP math?
Andrew John Hughes
gnu_andrew at member.fsf.org
Thu Feb 28 01:51:50 PST 2008
On 28/02/2008, Alan Eliasen <eliasen at mindspring.com> wrote:
> Jim Pick wrote:
> > What's New In Kaffe 1.1.9
> > ----------------------------
> > * Removed support for native big math.
> I have to admit, I was *very* disappointed when I saw this. The fact
> that Kaffe could use the best-of-breed GMP libraries to perform
> operations with very large BigIntegers was the sole reason that I used
> and advocated Kaffe. It was the one place where programs run under
> Kaffe could be enormously, incredibly faster than other JVMs, often by
> factors of 1000 or even 100,000. The algorithms that replaced it are
> *vastly* slower for very large numbers.
> Why was this done? It constitutes a severe performance regression
> for many programs, and was already switchable so that it could be
> compiled in and used or not used at runtime if desired, or completely
> omitted from compilation if you didn't want it.
> While I am working very hard at implementing faster algorithms for
> the OpenJDK project, my best algorithms are still factors of about 100
> times slower than Kaffe/GMP for many large numbers, and nothing one
> could do in Java could ever match their performance.
> How much trouble would it be for whoever removed these parts to
> revert those changes? I think they were removed without concern for the
> people who use Kaffe for this very reason, and this reason alone. For
> me, and the people that use Kaffe/GMP for work in number theory, this is
> a heartbreaking regression, and one that, quite frankly, makes Kaffe
> rather unsuitable for my use, as it tends to be about 20-25 times slower
> than other JVMs for most other programs.
> Alan Eliasen | "Furious activity is no substitute
> eliasen at mindspring.com | for understanding."
> http://futureboy.us/ | --H.H. Williams
> kaffe mailing list
> kaffe at kaffe.org
I obviously can't speak for Dalibor's motives on this, but I believe
the reason for removing GMP from Kaffe was to reduce the amount of
maintenance involved. The intention is to instead maintain such class
library extensions in GNU Classpath itself, so GMP support will be
added there (thus giving this same performance advantage to many VMs).
On that subject, Dalibor, can you point me at Raif's patch for adding this?
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