In the light of the recent benchmark discussion, a volunteer imported the tuning man-page into the wiki. Some comments at some places for possible improvements are already made. Please go over there, have a look, and participate please (testing/verification/discussion/improvements/…).
As always, feel free to register with FirstnameLastname and tell a FreeBSD committer to add you to the contributors group for write access (you also get the benefit to be able to register for an email notification for specific pages).