Benchmark is your friend here. just try out all these methods a few times and see what goes faster. And you don't have to install the module from cpan, its already part of the distribution. here's a skeleton of one run for any piece of code you want benchmarked.

use strict;
use Benchmark;
    my $t0 = new Benchmark;
    # ... your code here ...
    my $t1 = new Benchmark;
    my $td = timediff($t1, $t0);
    print "the code took:",timestr($td),"\n";
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although, its advisable to run the same code several times, (say a few hundred times ) and then average out the time to get a better estimate of how long the piece of code takes. This can be done directly with the module as well, and is explained in the docs.