Live CD Performance
Launchpad Entry: https://launchpad.net/distros/ubuntu/+spec/live-cd-performance
Created: 2005-04-23 by MattZimmerman
Packages affected: casper
The boot time for the Ubuntu live CD should be comparable (or superior) to other popular live CDs.
The better the load time, the better the live CD experience, the greater chance an end user will want to use it and move on to installing Ubuntu or another distro.
- Instrumentation is required in order to identify bottlenecks. d-i logs stage 1, we can wrap init scripts to provide timing information on their startup. Bootchart would also be useful. Bootchart wraps init and would be used for instrumenting stage 2. It stores it information in the live cd system where it could be uploaded to a central location such as bugzilla.
- Enable DMA on livecd - it may not work on some systems, but it's effectively required
Readahead may be a performance win with 256MB or more, but slower otherwise. Verify with different memory configurations, and ensure that readahead is only enabled when it's a performance benefit. http://unit.aist.go.jp/itri/knoppix/readahead/index-en.html has figures for Knoppix on cloop.
Filesystem comparison - squashfs and unionfs may give a performance benefit. http://listas.hispalinux.es/pipermail/metadistros-dev/2005-April/000580.html suggests a 50 second improvement.
Background network setup - this can be left for when the user has hit the desktop (NetworkMagic)
Data Preservation and Migration
For instrumentation, init requires modification or bootchart, which will be a better choice. Performance issues in the first stage install will require d-i modifications. Any slow packages in second stage boot will need tweaks to improve performance.
User Interface Requirements