From: Chad Perrin <perrin@...>
Date: 2007-09-25T06:44:19+09:00
Subject: Re: How fast does your Ruby run?

On Mon, Sep 24, 2007 at 11:26:15PM +0900, M. Edward (Ed) Borasky wrote:
> Chad Perrin wrote:
> > 
> > I find that rather surprising.  The common wisdom seems to be that newer
> > compiler versions tend to optimize more aggressively for the common case,
> > and take longer to compile as a result -- but tend to cause problems for
> > performance with multithreaded applications because until very recently
> > that hasn't been a priority for most compilers.  Falling performance for
> > the same code on newer compiler versions makes me wonder what else is
> > going on in compiler development.  If you have any insights, I'd like to
> > know about it.
> 
> The phenomenon is specific to gForth/vmgen and not a general rule as far
> as I know. The "general rule" is that newer compilers do better on newer
> architectures and "about the same" in the sense of statistical
> significance on the older ones.
> 
> gForth/vmgen has some very specific dependencies on gcc itself -- it
> uses some non-standard extensions to the C language in gcc and
> aggressively goes for putting things in registers, something most
> programmers wouldn't risk doing.
> 
> Another example is the ATLAS linear algebra library. Again, this is
> highly tuned C code (and now even has some assembler kernels). GCC 3 was
> significantly better than early versions of GCC 4 on 32-bit
> architectures. I don't recall if GCC 4 is now equivalent, and the point
> may be moot if the assembler kernels were introduced as a result.

Thanks for the info.  I may have to investigate further, with this as
some hints for where to start.


> 
> > I wonder if Ruby 1.9 would compile with the TenDRA compiler. . . .
> 
> I've never heard of it.

  http://www.tendra.org/about/

-- 
CCD CopyWrite Chad Perrin [ http://ccd.apotheon.org ]
Leon Festinger: "A man with a conviction is a hard man to change. Tell him
you disagree and he turns away. Show him facts and figures and he questions
your sources. Appeal to logic and he fails to see your point."