in reply to Single Quotes Versus Double Quotes

Everyone seems to be right. The difference is tiny. 
use strict;
use warnings;
use Benchmark ('cmpthese');

cmpthese(1000000, {
                 double => \&dq,
                 single => \&sq,
                 none   => \&nq
                });

sub dq {
  my $str = "a" x 100;
  my $new_val = "$str";
}

sub sq {
  my $str = "a" x 100;
  my $new_val = '$str';
}

sub nq {
  my $str = "a" x 100;
  my $new_val = $str;
}

[download]
Produces 
            Rate double single   none
double 1030928/s     --   -10%   -15%
single 1149425/s    11%     --    -6%
none   1219512/s    18%     6%     --

[download]


grep
One dead unjugged rabbit fish later

Replies are listed 'Best First'.
Re^2: Single Quotes Versus Double Quotes
by ikegami (Patriarch) on Oct 12, 2006 at 16:43 UTC
    You're comparing assinging a string of 4 characters to assigning a string of 100 characters. I don't see the relevance to the topic at hand. Here's a more relevant benchmarks. 
    Compile-time difference

          Rate single double
single 30027/s     --    -0%
double 30160/s     0%     --

Run-time difference

            Rate single double
single 5968932/s     --   -13%
double 6893402/s    15%     --

            Rate double single
double 6218672/s     --   -12%
single 7062848/s    14%     --

    [download]

    I'm getting lots of variation in the run-time results. The differences are probably due to external sources. Since the opcodes are the same, they should take the same amount of time. 

    use strict;
use warnings;

use Benchmark qw( cmpthese );

my $as = 'a' x 100;

sub c_dq {
  eval "\$a = \"$as\";";
}

sub c_sq {
  eval "\$a = '$as';";
}

eval "sub r_dq { \$a = \"$as\"; }";

eval "sub r_sq { \$a = '$as'; }";

print("Compile-time difference\n");

cmpthese(-3, {
   double => \&c_dq,
   single => \&c_sq,
});

print("Run-time difference\n");

cmpthese(-3, {
   double => \&r_dq,
   single => \&r_sq,
});

    [download]
[reply]
[d/l]
[select]

In Section Seekers of Perl Wisdom