You're right. I'm surprised too (not least because map could actually be implemented that way within perl...). I get a lot of variability (perl 5.8.8, x86_64-linux-gnu-thread-multi), but the for loop is a little faster.

All the comments about better style still stand, but I would certainly have expected the map to be faster. This is odd. Anyone have a 5.10 to hand to see if anything has changed?

Sidenote:

# Populate list with 10 mio numbers
for (my $i=0; $i<1000_000; $i++) {
    push @results, $i;
}
[download]

is perhaps better written as: my @results = (0..1_000_000); (Of course, given your observation regarding map, whether it performs better is now a whole 'nother ball of wax.)