[SRU] Set the default IO scheduler to CFQ in Kubuntu Trusty

Steve Langasek steve.langasek at ubuntu.com
Thu Oct 9 16:02:04 UTC 2014

On Thu, Oct 09, 2014 at 05:39:33PM +0200, Rohan Garg wrote:
> > So while I still don't agree that this is free of risk of regression (e.g.,
> > a system with both kubuntu and ubuntu desktops installed could see a direct
> > regression under the ubuntu session as a result of this change), I also
> Could you elaborate a bit on how this would affect the unity session? Sure
> performance might take a hit in certain cases, and we're very well
> aware of that,

As I said, the switch to deadline was seen to address existing problems with
applications on the unity desktop (when running on an HDD) becoming
non-responsive under heavy I/O.  Switching back to cfq is likely to
reintroduce this problem.

> but the pro's of changing the scheduler to cfq in order to get better
> performance in a KDE session
> outweigh this performance hit ( if there is one ).

How do they outweigh it?  I think you can only say they outweigh it if
you're running the Kubuntu desktop.  If you're running the Ubuntu desktop,
but have the Kubuntu desktop installed, you will have a different

I thought that Edubuntu was still including both Ubuntu and Kubuntu on their
DVD, which would be a clear example of why this would be the case.  It
doesn't look like Kubuntu is on that image anymore, so maybe this is a
negligible use case.

Steve Langasek                   Give me a lever long enough and a Free OS
Debian Developer                   to set it on, and I can move the world.
Ubuntu Developer                                    http://www.debian.org/
slangasek at ubuntu.com                                     vorlon at debian.org
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