qwurx [shmem] ~> perl 574821.pl 6000 7000 10000
Array size: 10000
Inserting: 6000 .. 7000
           Rate splicing  radiant
splicing 46.8/s       --     -66%
radiant   137/s     193%       --

##</code><code>##

# called as insert1( \@ary, 1, $_ ) for $START .. $END
sub insert1 {
  my ( $ra, $index, $elem ) = @_;
  @$ra = @$ra[0 .. $index-1], $elem, @$ra[$index .. @$ra-1];
}
# I tested with 
sub insert1 {
  my ( $ra, $elem, $index ) = @_;
  @$ra = @$ra[0 .. $index-1], $elem, @$ra[$index .. @$ra-1];
}
# called as insert1( \@ary, 1, $_ ) for $START .. $END

##</code><code>##

qwurx [shmem] ~> perl 574821.pl 600 700 1000 
Array size: 1000
Inserting: 600 .. 700
           Rate  radiant splicing
radiant  30.5/s       --     -98%
splicing 1672/s    5377%       --

##</code><code>##

$ perl -v
This is perl, v5.8.8 built for i586-linux-thread-multi
...