[Bug 1833322] Re: Consider removing irqbalance from default install on desktop images

[Christian Ehrhardt ]

Hi Mike

> SUSE ... says that the first step to get there is to disable
irqbalance

I've read the same, IMHO that is just "if you want to manually tune, disable
it" which does not imply that it is bad to have it. But this is how I read
it, I have not talked to the authors to get their underlaying reasoning.


> Applications vendors ... currently recommend removing irqbalance

The only one that does so AFAICS is cpufreq and everyone else just links
to their reasoning and follows. And even some statements there like
"If you are still running irqbalance, you are not getting the maximum
performance your system is capable of!" are hard to believe as a general
statement - especially without data across a wide variety of system types
and workload.
As we have seen as well in the references linked, irqbalance helps just as
much for "maximum performance" in many other cases.

> I found this blog (https://blogs.oracle.com/linux/post/irqbalance-
design-and-internals)

Thanks, every extra background we find will only help (except for those
joining later to read more).

> The question I have is, if Ubuntu is Debian Branch, and we long ago went
> from having different kernels for desktop & server in ubuntu-base, but do
> have ubuntu-server packages and ubuntu-desktop packages, where things could
> be different, why is this still a broad sweep as a default install "for all"?

Because there was no well-funded conclusion like "it really is bad for
environment X" to remove it. You are right that there are no technical blockers
to make it e.g. kept in servers but no more the default in Desktop.
After all it is already dropped in cloud-images used in virtual environemnts as
it had a more clear reasoning and argument there.

And there are also cases where irqbalance missing caused performance impact
and bug reports like the already mentioned [1] (clearly high scale server
though)


> I am happy that this is getting discussed properly now so that we can
> relook at this, and what it means to us today.

Ack, that is why I tried to compile all I've found into one place.


[1]: https://bugs.launchpad.net/ubuntu/+source/irqbalance/+bug/2038573

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https://bugs.launchpad.net/bugs/1833322

Title:
  Consider removing irqbalance from default install on desktop images

Status in irqbalance package in Ubuntu:
  Confirmed
Status in ubuntu-meta package in Ubuntu:
  Confirmed

Bug description:
  as per https://github.com/pop-os/default-settings/issues/60

  Distribution (run cat /etc/os-release):

  $ cat /etc/os-release
  NAME="Pop!_OS"
  VERSION="19.04"
  ID=ubuntu
  ID_LIKE=debian
  PRETTY_NAME="Pop!_OS 19.04"
  VERSION_ID="19.04"
  HOME_URL="https://system76.com/pop"
  SUPPORT_URL="http://support.system76.com"
  BUG_REPORT_URL="https://github.com/pop-os/pop/issues"
  PRIVACY_POLICY_URL="https://system76.com/privacy"
  VERSION_CODENAME=disco
  UBUNTU_CODENAME=disco

  Related Application and/or Package Version (run apt policy $PACKAGE
  NAME):

  $ apt policy irqbalance
  irqbalance:
  Installed: 1.5.0-3ubuntu1
  Candidate: 1.5.0-3ubuntu1
  Version table:
  *** 1.5.0-3ubuntu1 500
  500 http://us.archive.ubuntu.com/ubuntu disco/main amd64 Packages
  100 /var/lib/dpkg/status

  $ apt rdepends irqbalance
  irqbalance
  Reverse Depends:
  Recommends: ubuntu-standard
  gce-compute-image-packages

  Issue/Bug Description:

  as per konkor/cpufreq#48 and
  http://konkor.github.io/cpufreq/faq/#irqbalance-detected

  irqbalance is technically not needed on desktop systems (supposedly it
  is mainly for servers), and may actually reduce performance and power
  savings. It appears to provide benefits only to server environments
  that have relatively-constant loading. If it is truly a server-
  oriented package, then it shouldn't be installed by default on a
  desktop/laptop system and shouldn't be included in desktop OS images.

  Steps to reproduce (if you know):

  This is potentially an issue with all default installs.

  Expected behavior:

  n/a

  Other Notes:

  I can safely remove it via "sudo apt purge irqbalance" without any
  apparent adverse side-effects. If someone is running a situation where
  they need it, then they always have the option of installing it from
  the repositories.

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