The benchmark above shows the cost of the "my" in the loop. This compares both lexical approaches with the package variable (aka "global") approach: 

my $foo;
our $foo2;

cmpthese(shift, {
        'test_1' => sub { $foo = 1; },
        'test_2' => sub { my $bar = 1; },
        'test_3' => sub { $foo2 = 1; },
    });

__END__
            Rate test_2 test_1 test_3
test_2 3731343/s     --   -30%   -37%
test_1 5347594/s    43%     --   -10%
test_3 5952381/s    60%    11%     --

[download]

But the apparent gaps diminish rapidly as you start doing even a little work, particularly if system interaction is involved:

my $foo;
our $foo2;

cmpthese(shift, {
        'test_1' => sub { $foo = time; $foo += 1 if __PACKAGE__ eq 'ma
+in' },
        'test_2' => sub { my $bar = time; $bar += 1 if __PACKAGE__ eq 
+'main' },
        'test_3' => sub { $foo2 = time; $foo2 += 1 if __PACKAGE__ eq '
+main' },
    });

__END__
           Rate test_2 test_3 test_1
test_2 442478/s     --    -4%   -10%
test_3 462963/s     5%     --    -6%
test_1 492611/s    11%     6%     --

[download]

Interesting that the order reverses, thought it might just margin of error

-xdg

Code written by xdg and posted on PerlMonks is public domain. It is provided as is with no warranties, express or implied, of any kind. Posted code may not have been tested. Use of posted code is at your own risk.

In reply to Re^2: Time Penalty vs. Global Symbols by xdg
in thread Time Penalty vs. Global Symbols by Dismas

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