$ cat foo.pl ; echo "--------";echo; ./foo.pl 
#!/usr/bin/perl 
##################
use Benchmark qw(:all) ;

sub test1(){
$entries = @{[ split ]};
}

sub test2(){
$entries = () = /\S+/g;
}

$_="This is an example string with several words bla bla bla\n";
$count=1E+7;
timethis ($count, "test1()");
print "------------\n";
timethis ($count, "test2()");


--------

timethis 10000000: 13 wallclock secs (12.37 usr +  0.01 sys = 12.38 CPU) @ 807754.44/s (n=10000000)
------------
timethis 10000000:  7 wallclock secs ( 6.66 usr +  0.00 sys =  6.66 CPU) @ 1501501.50/s (n=10000000)