It does, here are some numbers: 
       Six: 10 wallclock secs ( 4.82 usr +  5.18 sys = 10.00 CPU) @ 43
+7.30/s (n=4373)
       One: 13 wallclock secs (12.92 usr +  0.01 sys = 12.93 CPU) @  4
+.87/s (n=63)
      Five: 13 wallclock secs (13.39 usr +  0.00 sys = 13.39 CPU) @  5
+.15/s (n=69)
      Four: 10 wallclock secs ( 4.74 usr +  5.56 sys = 10.30 CPU) @ 44
+3.69/s (n=4570)

[download]
The code for this is: 
#!/usr/bin/perl -w
use strict;
use Benchmark;
my $testlarge = "a " x 100000;
my $testsmall = "a b c d e f";
timethese(-10,{
        One   => sub { my ($y) = (split(/\s+/,$testlarge))[0]; },
        Two   => sub { my ($y) = (split(/\s+/,$testsmall))[0]; },
        Three => sub { $testsmall =~ /([^\s]*)\s+/; my $y = $1; },
        Four  => sub { $testlarge =~ /([^\s]*)\s+/; my $y = $1; },
        Five  => sub { my  $y  =  split(/\s+/,$testlarge)      },
        Six   => sub { my ($y) =  split(/\s+/,$testlarge,1)    }
              });

[download]
Note that using an equivalent regex is slightly faster, but the split done properly (using the third arguement) preforms at the "correct" level.

Thanks for submitting the correct answer :) hehe.

Chow,
Gryn

In reply to Using the third arguement for split by gryng
in thread is split optimized? by Anonymous Monk

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