comment on

Not a fair comparison. You're creating an entirely new SV every time, whereas the OP was using an existing ref.

$Contracts{$key}[STATE]
[download]

my $r = $Contracts{$key};
$r->[STATE]
[download]

is not similar to

$Contracts{$key}
[download]

my $r = \$Contracts{$key};
$$r
[download]

Update:

My benchmark:

use strict;
use warnings;

use Benchmark qw( cmpthese );

use constant NUM_KEYS     => $ARGV[0];
use constant NUM_ACCESSES => $ARGV[1];
use constant TEST_TIME    => $ARGV[2];

our %contracts = map { $_ => [ 0 ] } 1 .. NUM_KEYS;

my $lookup = '
   foreach (keys %contracts) {
      _____
  }
';
$lookup =~ s/_____/'$a = $contracts{$_}[0];' x NUM_ACCESSES/e;

my $refit = '
   foreach (keys %contracts) {
      my $r = $contracts{$_};
      _____
  }
';
$refit =~ s/_____/'$a = $r->[0];' x NUM_ACCESSES/e;

cmpthese(TEST_TIME, {
   lookup => $lookup,
   refit  => $refit,
});
[download]

My results:

>perl 586841.pl 500 4 -5
         Rate lookup  refit
lookup 1060/s     --    -4%
refit  1101/s     4%     --

>perl 586841.pl 500 4 -5
         Rate lookup  refit
lookup 1053/s     --    -5%
refit  1105/s     5%     --


>perl 586841.pl 500 6 -5
        Rate lookup  refit
lookup 772/s     --   -11%
refit  869/s    13%     --

>perl 586841.pl 500 6 -5
        Rate lookup  refit
lookup 775/s     --   -11%
refit  873/s    13%     --


>perl 586841.pl 500 10 -5
        Rate lookup  refit
lookup 496/s     --   -19%
refit  614/s    24%     --

>perl 586841.pl 500 10 -5
        Rate lookup  refit
lookup 499/s     --   -19%
refit  613/s    23%     --
[download]

Verdict: It's a fruitful optimization, but it's not ground breaking.

In reply to Re^2: Ref to hash entries are faster? by ikegami
in thread Ref to hash entries are faster? by Wiggins

Are you posting in the right place? Check out Where do I post X? to know for sure.
Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
<code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>
Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
Want more info? How to link or How to display code and escape characters are good places to start.


go ahead... be a heretic
	PerlMonks