Platform

Revision 8 as of 2008-05-27 13:20:47

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UDS Intrepid Platform Report

[:UDS-Intrepid/Report:back to the reports index page]

Plans for 8.10

Place in this section bullet points of specific intended outcomes for the 8.10 development cycle.

  • Outcome
  • Outcome

Sessions

Session

19 May Round Table

Boot performance

We need faster boots for various reasons: mobile, laptop, etc. It's also just generally nice.

Overview

boot process spends a lot of time in initramfs:

  • initramfs stuff written in shell -> slowish

  • probing is fast, except for some systems like mobile stuff (ogra)
  • cpu is finite, but fast
  • ram is fast, we don't care about it much
  • disk is really, really slow
  • readahead is a static list that should be regenerated often to be really useful

  • flash devices should not use readahead-->Detect type of disk.

  • readahead is up to date after a new fresh install
  • prefetch is a potential new way of doing what readahead does

Readahead problems: 1) operates on file-by-file basis 2) generating the lists is very difficult

Prefetch is kernel-level

  • works on disk blocks => more efficient

  • essentially self-updating
  • however, needs some work to be actually usable (at least for this)
  • documentation!

during boot, we're cpu bound during modprobe (via udev?). mobile is almost entirely cpu bound

  • Keybuk: udev-settle is completely pointless, udev could just be started early
  • plan to do that, is after intrepid, probably intrepid+1

  • Artir:Use bootchart to check boot time changes caused by improvements.

rc2 is highly subjective to people's configurations (but we could benchmark default install)

mobile with fixed hardware may gain a lot of boot speed by compiling drivers into the kernel

X/gdm should start earlier, but this requires dbus+hal to be started earlier

Goal 25 secs?(On Core2Duo, 1 Gb Ram p.e.). Less on QuadCore systems?

Solutions

  1. Use multithreading. Take advantage of multi-core systems.-->Detect processor.

  2. Auto regenerative readahead and grub autoprofiler.

  3. Preload&Prefetch&Grub auto-profiler by default

  4. Restructure boot order

Plan for intrepid:

  • prefetch
  • Better multithreading
  • dbus, hal moving to upstart
  • elimiante udev settle
  • stop X from stating like crazy at startup.(Kernal based modesetting)

20 May Round Table

Ubuntu Distributed Development - Importer

  • Aim to have all of Ubuntu, and possibly Debian imported during the
    • Intrepid cycle.
  • Use the upcoming features in bzr and launchpad to make it very quick
    • to make small changes.

OpenOffice.org upload schedule

OpenOffice.org language packs

21 May Round Table

  • Notes
  • Notes

Upgrade hints (really: remove cruft after upgrades)

Post-hoc hints for cleaning up system from non-update-manager upgrades; incorporate:

  • apt-get autoremove
  • replacement of now-unsupported packages
  • cleaning up old kernels (has been pending for ages, should happen independent of the rest)
  • deborphan?
    • finds rather more packages for apt-get install users, so still useful for several people
  • deprecated dotfiles?
  • purging removed packages with configuration files
    • only unmodified conffiles (or ucf-managed files)?
      • code for this in unattended-upgrades already (mvo)
  • .dpkg-old/new files?
  • the cruft program exists (used to?)
  • random files belonging to packages that aren't removed by remove
    • (piuparts finds these)

Michael reluctant to add to update-manager UI itself; update-manager should only install packages, not remove them, otherwise people will be more reluctant to run it

Most applications of a cleanup tool are package-related

Need to add upgrade hints for certain packages moved from main to universe. Also installer changes (e.g. relatime)

Code in update-manager mostly fairly separate

Some is more difficult to perform after installation due to lack of context (e.g. no knowledge of previous state)

  • libapt could record previous state in its extended_states file

Cleanup items need to have a "no, and don't ask me again" option, which is difficult to incorporate into current update-manager design

Loose consensus to add new System -> Administration entry for this tool due to this; mvo and liw to talk with mpt

USB installation images

Targets

  • Ubuntu desktop installable USB key
  • Netbook/Classmate installation
  • Ubuntu Mobile? (much less user interaction required/desired)
  • Ubuntu alternate installable USB key
  • Ubuntu server installable USB key

Design

  • Don't want to ship (and mirror) yet another 700M blob
  • Prefer to have a tool which accepts an Ubuntu .iso as input and writes the necessary bits to a USB stick
  • Linux-only tool in first iteration, Windows later (unless volunteers materialise)

    • Write in Python, use IronPython to ship .NET object code?

    • Windows can also boot a live CD and transform to USB stick

Advantages

  • No CD waste
  • Possibility to have 1 Gb ubuntu image (300 more Mb of space)
  • No need for optical drive
  • Faster. (USB has 480 Mb per second and CD-ROM 52X has 62 Mb per second)

Notes from previous discussion (UDS-Seville)

Live/Install from USB key

  • Much faster for ISO testing
  • Avoid "CD blanks"
  • Works on machines without optical drive
  • USB key is a mass storage device (a hard drive)
    • Rather than a floppy disk

Use cases

Results

  • Modify installer to check for:

    • /ubuntu*.iso containing either a .deb local repo

      • Already done for hd-media installer (alternate-style)
    • Live Ubuntu image containing a squashfs
  • Prefer copying entire file tree to USB image
    • Simpler
    • Guaranteed to work even with 4.3GB DVD images (VFAT limit is 4.0GB)

Needs research

  • Relationship to smart-boot-manager
  • Syslinux/isolinux
    • Syslinux wrapper writes a bootsector "blob" to the front of the CD
      • opens as vfat with mtools
      • writes out ldlinux.sys
      • copies syslinux code (ldlinux.bss) into bootsector
  • We can do the equivalent under MS Windows (rawrite) provided that we ship the two files above on the CD
    • Question: can we access the raw device without Administrator privileges?

  • http://www.weethet.nl/english/hardware_bootfromusbstick.php

    • Method involving the MS Windows formatting "[x] Create start up disk".

Targets

  • Desktop CD/DVD on USB --- (direct dd > /dev/sdb); should work but believed to be buggy at the moment

  • Desktop CD/DVD on USB with local ISO --- not interesting (except for having a small bootstrap image)
  • Desktop CD/DVD on USB with persistence
  • Netboot on USB with network fetch
  • Netboot on USB with local alternate .iso

Wants

Transformation utility that takes a .iso image and it works out what to do with it

Should work for Linux and Windows, so possibly two separate applications

  • "Write to USB key?"
  • MAKE THE DESKTOPCD ON USB WORK.
    • Makes ISO testing easier
    • The place where we have less technical users.
    • Persistence?
    • ALREADY COVERED BY WUBI!
  • Casper to look for .iso and look inside for squashfs, mount boot that
    • Hunt though top-level directories
      • Modify checkdev in casper, recurse one level.
        • Already done for wubi installer.
  • Make persistency not check for partition label
  • Copy /contents/ of .iso image to vfat.
  • Copy .iso to USB stick
  • Fish vmlinuz and initrd out of .iso
  • Run syslinux
  • Make a Unix script to do this
  • Ask somebody to reimplement for MS Windows
  • Point to this from the CD download pages.
  • Provide a mini DesktopCD dd-able image of the above.

Ubuntu policy manual and standards

Documents describing policy and standards are difficult to track in the wiki:

  • no changelog
  • completely lost if you return after a break
  • no upgrading-checklist.txt

https://wiki.ubuntu.com/UbuntuPackagingChanges

debian-policy is mostly appropriate except for section 3

it's important to preserve section numbers

developers-reference for workflow

Refer to UbuntuArchitecture

Policy changes:

  • Maintainer
  • python-minimal
  • Components and sections
  • Seeds
  • Upstart
  • /var/run as a tmpfs (also should go to Debian)
  • udev changes compared to debian
  • casper
  • Package versioning

  • See UbuntuPackagingChanges

  • experimental -> PPA

  • Standards-Version: should refer to the ubuntu policy?
    • Avoid frivolous Standards-Version: diffs
  • call it ubuntu-policy, keep debian-policy in archive identical to Debian's

Developer's reference:

  • Merging
  • Resources such as ubuntuwire.com and REVU
  • Language packs

  • Branding (cf. DistributionDefaultsAndBranding

  • Source-only uploads (incl. lack of binNMUs)
  • References to archive structure, admin, etc.
  • Release scheduling: perhaps external reference
  • Require upgradeability between LTS releases (policy or reference?)
    • Some kind of argument about partial upgrades

Announcement of changes:

  • including merged changes from Debian
  • diffs sent to ubuntu-devel
  • changelog (or similar) sent to ubuntu-devel-announce

Revitalise ubuntu-devel!

Lightweight process on ubuntu-devel for making changes

  • Post proposed change (description or diff)

  • If no objections, anyone else may apply diff (to avoid one-man changes)

  • If objections, discuss

Spec: foo