casper very slow on armel+imx51

We're already setting LIVEMEDIA, I'm a bit surprized that it's not picked up; perhaps we need a rootdelay as well.

it seems this is due to "udevadm trigger" or "settle" which are used in casper ATM.

This must be a bug in udev or the kernel, rather than casper. Is it still the same in Karmic?

So I just tested booting karmic alpha 6; the boot is still very slow albeit faster; I didn't have SATA connected either.

I dont know whether the SATA part is relevant here; I think it's just the amount of stuff casper does which takes too long on armel. Things like generating locales take forever.

I'd suggest you add a little timestamp to call_scripts() in /usr/share/initramfs-tools/scripts/functions, so that we can see in casper.log what takes so much time.

Related blueprint for reference: https://blueprints.launchpad.net/ubuntu/+spec/mobile-lucid-une-casper-speedup

Initial finding from time-stamping. Time stamps are in time format (hour:min:sec).

Seems the biggies are 10adduser and 19keyboard.

[04:59:48] Calling hook 10driver_updates
[04:59:48] Calling hook 20iso_scan
[04:59:48] Calling hook 30custom_installation
[04:59:50] Calling hook 01integrity_check
[04:59:50] Calling hook 05mountpoints
[04:59:50] Calling hook 05mountpoints_lupin
[04:59:50] Calling hook 10adduser
Shadow passwords are now on.
[05:00:16] Calling hook 10custom_installation
[05:00:16] Calling hook 10ntfs_3g
[05:00:16] Calling hook 12fstab
[05:00:16] Calling hook 13swap
[05:00:16] Calling hook 14locales
Generating locales...
  en_US.UTF-8... done
Generation complete.
[05:00:24] Calling hook 15autologin
[05:00:24] Calling hook 18hostname
[05:00:24] Calling hook 19keyboard
[05:00:47] Calling hook 20xconfig
[05:00:47] Calling hook 22gnome_panel_data
[05:00:48] Calling hook 22screensaver
[05:00:49] Calling hook 22serialtty
[05:00:49] Calling hook 22sslcert
[05:00:54] Calling hook 23etc_modules
[05:00:54] Calling hook 23networking
[05:00:55] Calling hook 24preseed
[05:01:06] Calling hook 25configure_init
[05:01:07] Calling hook 30accessibility
[05:01:07] Calling hook 31disable_update_notifier
[05:01:07] Calling hook 32disable_hibernation
[05:01:08] Calling hook 33enable_apport_crashes
[05:01:08] Calling hook 34disable_kde_services
[05:01:08] Calling hook 35fix_language_selector
[05:01:12] Calling hook 36disable_trackerd
[05:01:12] Calling hook 37kubuntu_netbook_installer_link
[05:01:12] Calling hook 40install_driver_updates
[05:01:12] Calling hook 41apt_cdrom
Using CD-ROM mount point /cdrom/
Identifying.. [4dc8ab4694d3b0e7528f442bee3567df-2]
Scanning disc for index files..
Found 1 package indexes, 0 source indexes, 0 translation indexes and 1 signatures
Found label 'Ubuntu 9.10 _Karmic Koala_ - Release armel+imx51 (20091027.2)'
This disc is called:
'Ubuntu 9.10 _Karmic Koala_ - Release armel+imx51 (20091027.2)'
Copying package lists...gpgv: Signature made Tue Oct 27 21:59:50 2009 UTC using DSA key ID FBB75451
gpgv: key FBB75451 was created 1104415711 seconds in the future (time warp or clock problem)
gpgv: key FBB75451 was created 1104415711 seconds in the future (time warp or clock problem)
gpgv: Can't check signature: timestamp conflict
E: Sub-process gpgv returned an error code (2)
W: Signature verification failed for: /cdrom/dists/karmic/Release.gpg
[05:01:13] Calling hook 42disable_apparmor
 Removing any system startup links for /etc/init.d/apparmor ...
   /etc/rcS.d/S37apparmor
[05:01:13] Calling hook 43disable_updateinitramfs
[05:01:13] Calling hook 44pk_allow_ubuntu
[05:01:13] Calling hook 45disable_guest_account
(Reading database ... 129861 files and directories currently installed.)
Removing gdm-guest-session ...
Purging configuration files for gdm-guest-session ...
[05:01:21] Calling hook 46disable_services
[05:01:21] Calling hook 47unr_ubiquity
No value set for `/apps/netbook-launcher/favorites/favorites_list'
No value set for `/apps/netbook-launcher/favorites/favorites_list'
No value to set for key: `/apps/netbook-launcher/favorites/favorites_list'

This matches my experience; the keyboard setup is also slow under ubiquity.

19keyboard: is it all the casper-preseed calls that are slow, or the install-keymap command? I also noticed plenty of unnecessary uses of chroot, and a very old TODO comment that probably could need some love.

10adduser: I can imagine the debconf-communicate calls are expensive, otherwise there is not much in there.

Can you try to profile these by hand? Boot with break=casper-bottom and run the scripts with sh -x to see where they are sticking.

The findings in a better format:

https://wiki.ubuntu.com/ARM/CasperSpeedup

10adduser:

chroot /root debconf-communicate -fnoninteractive casper > /dev/null <<EOF
set passwd/root-password-crypted *
set passwd/user-password-crypted U6aMy0wojraho
set passwd/user-fullname $USERFULLNAME
set passwd/username $USERNAME
set passwd/user-uid 999
EOF

takes around 7 seconds.

chroot /root /usr/lib/user-setup/user-setup-apply > /dev/null

takes around 12 seconds.

chroot /root debconf-communicate -fnoninteractive casper > /dev/null <<EOF
set passwd/root-password-crypted
set passwd/user-password-crypted
set passwd/user-fullname
set passwd/username
set passwd/user-uid
EOF

takes around 4 seconds.

19keyboard:

Each of the

casper-preseed /root console-setup/layoutcode '' false
casper-preseed /root console-setup/variantcode '' false
casper-preseed /root console-setup/modelcode '' false

casper-preseed /root console-setup/optionscode '' false
casper-preseed /root console-setup/codesetcode '' false

Take around 4 seconds each.

Seems that the debconf-communicate calls are causing major slowness on ARM. This should be investigated further.

Cause is found. Its the parsing of the templates.dat file once per debconf-communicate call. Work is underway to use debconf-communicate persistently whilst it is needed by Casper to avoid the multiple reloading of the same file.

Changing the way casper uses debconf-communicate and a few other tweaks results in a boot speed-up of around 33% across architectures. e.g.

  i386: 30 secs to 20 secs
  armel (babbage): 180 secs to 113 secs

casper (1.216) lucid; urgency=low

  [ Luke Yelavich ]
  * scripts/casper-bottom/30accessibility && ubiquity-hooks/30accessibility:
    - Remove code to disable pulseaudio, as it is no longer needed, and
      the supporting code in the pulseaudio package was removed a long time
      ago.
    - Set the default empathy theme to classic for blindness and braille
      accessibility profiles.

  [ Jamie Bennett ]
  * Speed up work around debconf-communicate. Replace several calls to
    debconf-communicate with one persistent invocation followed by
    confmodule calls.
  * Disable guest account by rm'ing rather than waiting for dpkg to
    remove it.

 -- Colin Watson <email address hidden> Wed, 03 Feb 2010 16:41:57 -0800