On Mon, Jan 16, 2017 at 06:07:42PM -0600, Michael Catanzaro wrote:
It includes a couple recommendations:
* We should restore systemd-readahead to speed boot time by ~30% for
users without SSDs. Endless has a downstream patch for this. Or we
could use Ubuntu's readahead utility.
Has Endless done benchmarks? I'd hate to renable it based mainly on
anecdotes. If it turns out to be worthwhile, it'd be nice to work with
Endless to get the feature back upstream in systemd - if I remember
right, one of the points at its removal was that the main developers
didn't have the spinning-disk hardware to benefit from it and that no
one who cared stepped up. If it turns out that there _are_ people who
care, upstream seems like the right home.
* We should switch from CFQ to deadline I/O scheduler (which Ubuntu
has been using for years) for subjective massive responsiveness
improvements when the system is under load
Same point about benchmarks applies here, although it's a lot less work
to experiment with and the consequences easily reversed. FWIW, RHEL 7
defaults to deadline on all devices except SATA disks, which default to
CFQ. And on virtual disks, you get no IO scheduling at all, which makes
sense and makes this irrelevant in those cases.
Of these, the later seems easier to change and more important.
know why we're still using CFQ? If the answer is "it's better for
servers" then perhaps we need a mechanism to adjust this on a per-
Dunno, but doing it per-edition might make sense. At least, unless the
above is applicable for everything.
Fedora Project Leader