Bug#925160: systemd: user session slow to start (11 seconds)

["Aaron M. Ucko" <ucko@debian.org>]

Package: im-config
Version: 0.39-1
Followup-For: Bug #925160

I've also encountered slowness here, sometimes to the point of
tripping systemd timeouts.  The culprit appears to be repeatedly
searching /usr/lib via find -- on the system where this issue has
bitten me most badly, I have hundreds of thousands of directory
entries there (yes, I'm a packrat):

  $ locate /usr/lib/ | wc -l
  864543

Here are a few suggestions for ways to do better here:

* Bail right away for non-graphical sessions (possibly extending to
  ssh sessions with X forwarding).

* Use shell globbing (ls or even echo) rather than find ... -path ...
  unless you specifically need to traverse an unknown number of
  directory levels.
** You can probably rely on multiarch specifiers to contain hyphens:
   /usr/lib/*-*/gtk-2.0/*/immodules/im-ibus.so

* If you really do need find, consolidate searches more and split them
  back out as needed:
  IM_CONFIG_ALL_MARKERS="$(find /usr/lib \
                           -path '/usr/lib*/gtk-?.0/immodules/im-ibus.so' -o \
                           -path ... -o ...)"
  IM_CONFIG_MARKER="$(echo "$IM_CONFIG_ALL_MARKERS" | grep ...)"

* Search ahead of time on the basis of dpkg triggers, an apt hook,
  and/or a cron job (bearing in mind that cron job results may
  occasionally be inaccurate by the time sessions start).

Could you please consider them, or otherwise address this slowness?

Thanks!

-- System Information:
Debian Release: buster/sid
  APT prefers unstable-debug
  APT policy: (500, 'unstable-debug'), (500, 'testing-debug'), (500, 'testing'), (500, 'stable'), (300, 'unstable')
Architecture: amd64 (x86_64)
Foreign Architectures: i386, x32

Kernel: Linux 4.19.0-2-amd64 (SMP w/4 CPU cores)
Kernel taint flags: TAINT_PROPRIETARY_MODULE, TAINT_WARN, TAINT_OOT_MODULE, TAINT_UNSIGNED_MODULE
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages im-config depends on:
ii  gettext-base  0.19.8.1-9

Versions of packages im-config recommends:
ii  kde-baseapps-bin  4:16.08.3-3
ii  kdialog           4:17.08.3-2
ii  whiptail          0.52.20-8
ii  x11-common        1:7.7+19
ii  zenity            3.30.0-2

im-config suggests no packages.

-- no debconf information