Introduction

By measuring boot time in your setup you can help us improve boot prefetching to make boot even shorter.

Please install measurement script, perform the experiments and submit the results.

Installation of measurement script

This script measures boot time in repeatable manner. It should be run using your desktop environment autostart facility (not manually) in order to get consistent results. Your login manager (GDM, KDM or XDM) should be set to autologin your user in order to remove random time when you log in to the system.

To install measuring script: 1. Download script which logs boot time 1. Copy script into your home directory 1. Change script permissions to mark it executable 1. Add script to your desktop environment autostart scripts (for specific instructions see below)

Adding measurement script to KDE autostart

In order to add measurement script to KDE autostart: 1. Download desktop file which starts script 1. Copy this desktop file to folder ~/.kde/Autostart/

Adding measurement script to Gnome autostart

To be done. If you know how to do it, please send e-mail

Experiments

Now you can experiment to see what is the effect of prefetching kernel on your system. Boot a few times (at least 5 times, preferably 10) with prefetching (first run is not accelerated as trace does not exist), then a the same number of times with standard kernel (with and without readahead installed) and compare the results.

Results are put in file ~/boot_time.log. Lines starting with # are comments which show run parameters. Each reboot starts with line @restart. Results are put in lines without #, boot time (in seconds) is the first number in this line.

You can repeat tests after modifying your boot sequence: add apps to Autostart, install some services started during boot (like Apache) or otherwise change your boot sequence. Prefetching should automatically adapt to changed sequence after 1-2 reboots.

Suggested tests: 1. Boot with prefetching 1. Boot with prefetching disabled by appending prefetch_core.enabled=0 to kernel command line in /etc/grub/menu.lst 1. Boot with standard Ubuntu kernel without readahead 1. Boot with standard Ubuntu kernel with readahead (you have to reinstall readahead package which will replace prefetch userspace support package).

Submit your results

Please split ~/boot_time.log into separate files, so that run with one set of parameters is in separate file.

Please describe your environment (processor, RAM, partitions), attach results and send e-mail with results to prefetch-users@googlegroups.com with subject "Prefetch test results".