[JIRA] (BIT-1133) topic/jsiwek/dns-perf

-O0. I'm using instructions as a proxy for "work"; so far the
instruction number has turned out to be nicely stable across run on
the same machine. So I'm not saying that there's a precise 2% impact
but only that the DNS changes lead to now more work being done, which
I think warrants understanding given that DNS is just a small of piece
of everything. If we understand what's going on and deem it fine and
worth the cost, no problem. I'll do some more measurements and see how
actual timing looks like for me.