use strict;
use warnings;
use Time::HiRes qw(time);

open my $name_infh, '<', 'path/to/names/list' or die $!;
open my $haystack_infh, '<', 'path/to/tab/delimited/list' or die $!;

my $t0 = time();

while(<$name_infh>) {}
while(<$haystack_infh>) {}

printf "Elapsed time: %-.03f\n", time-$t0;