On Tue, Jan 17, 2017 at 6:38 PM, Matthew Miller mattdm@fedoraproject.org wrote:
On Tue, Jan 17, 2017 at 12:31:04PM -0500, Josh Boyer wrote:
Yes, but doing that across all of Fedora is pointless. What works for the majority of Server users won't necessarily work for Cloud or Workstation. Also, the end user's ability to even discover that it's tunable varies greatly from one Edition to the next. One could expect sysadmins knowing about this and changing the default on their Server install. The Workstation end user may not be as low-level detail aware and could just suffer with poor performance because they think that's the only option.
Well, I'm starting from Michael's premise that deadline would be better for latency for most desktop users (regardless of disk type), and clearly better when using SSD. This leads me to a different conclusion than the above.
It's irrelevant for cloud and any other virt deployment of Atomic or Server. As far as I know, the special case on hardware where cfq is better is the one I outlined (on hardware, single spindle, prefer throughput, mixed workload) and I agree that it's okay to expect sysadmins to handle that.
Well there are a few things to consider here ...
1) Afaik deadline does not support I/O priorities (ionice), whole CFQ does. Which might be harmful when you have processes like tracker competing for I/O in the background 2) What about external media? It might perform a bit better on internal disks but what about USB connected storage? 3) Given the recent developments upstream (BFQ and multi queue) shouldn't we rather wait for that?