I've put up the I/O scheduler that I've been working on into phabricator for review. A number of items likely will peel off this review, since it also has the NCQ support and a few other things. https://reviews.freebsd.org/D4609 Please comment in the review. For background see http://people.freebsd.org/~imp/talks/bsd2015/iosched-v3.pdf Warner