My guess is that sort is taking the majority of the time in your code. If your argument list is long enough passing it in as a list can take a decent chunk of time.
use Benchmark qw(cmpthese);
@a = 1..1_000_000;
sub flat { my $array = \@_ }
sub flatcopy { my @copy = @_ }
sub byref { my $array = $_[0] }
sub refcopy { my @copy = @$_[0] }
cmpthese(-1, {
flat => sub { flat(@a) },
flatcopy => sub { flatcopy(@a) },
byref => sub { byref(@a) },
refcopy => sub { refcopy(@a) }
});
__END__
Rate flatcopy flat refcopy byref
flatcopy 3.24/s -- -77% -91% -91%
flat 14.3/s 342% -- -59% -61%
refcopy 35.3/s 987% 146% -- -3%
byref 36.3/s 1020% 153% 3% --