$ time perl -e 'print scalar(()=glob"*"),$/'
136631

real    0m4.810s
user    0m3.340s
sys     0m1.320s

$ time perl -le 'opendir f, $ARGV[0] or die $!;++$c while readdir f; print $c' .
136633

real    0m0.440s
user    0m0.400s
sys     0m0.040s