It seemed easy enough... I want to extract irc‑logger.pl from my perl repository into it's own, so that I can make some refactoring. Easy enough, right?
svnadmin create irc-logger
svn mkdir -m "create trunk" file:///home/dpavlin/private/svn/irc-logger/trunk/
svnadmin dump perl | svndumpfilter include --drop-empty-revs trunk/irc-logger.pl | svnadmin load irc-logger/

Strange things I noticed:
I have to create directories needed to restore filtered dump manually, svndumpfilter could be clever about that, but it isn't (at least it has non‑default option ‑‑drop‑empty‑revs which should also be default, but isn't)