Speed v Version

Nicholas Clark nick at ccl4.org
Wed Jun 1 14:13:40 BST 2011

On Wed, Jun 01, 2011 at 02:00:14PM +0100, Dave Hodgkinson wrote:
> On 1 Jun 2011, at 11:57, Dave Lambley wrote:
> > 
> > My former employer did some benchmarking of different versions of Perl, used inside mod_perl.  Perl 5.10.x proved faster than 5.8.x, and 64 bit was faster than 32.  This was for a CPU bound application though, which it sounds like your's is not.

This was x86 vs x86_64? As I understand it, even though it can be on the same
chip, the latter CPU architecture has far more general purpose registers,
which permits compilers to generate better code...

> Bear in mind 64 bit mod_perl has a much larger memory footprint...

but then as Dave says, changing from x86 to x86_64 halves the amount of
(non-character, non floating point) stuff you can get in the same CPU's
caches, and in the same machine's RAM.

It's swings and roundabouts, so benchmarking and monitoring really is the way
to find out.

Nicholas Clark

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