On Tue, Jan 17, 2017 at 04:38:31PM +0100, Jiri Eischmann wrote:
I briefly spoke with Jiri Hladky, the manager of the FS perf team in
Red Hat, and he says that deadline is clearly better for SSD. Results
for rotating disks are mixed, but he'd still prefer deadline there,
too. He can provide more detailed info if we need it.
It's my understanding that CFQ is better in the case where you a) have
a single spinning disk with b) mixed workload on top of that and c)
care about overall throughput more than latency. An example might be if
you are a budget hosting provider and are running multiple VMs on
single-disk servers. If is preferred for lower latency on desktops, and
is overall preferred for servers (a win on RAID, on SSD, and even on
single-disk systems in many cases), switching to as across-the-board
default deadline seems like the straightforward choice.
I guess the next step is to engage the kernel team, and possibly FESCo
since this is obviously a big engineering steering decision. And
someone other than me can decide if this should be a Change.
--
Matthew Miller
<mattdm(a)fedoraproject.org>
Fedora Project Leader