Boot Time

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This page has information about reducing boot-up time for a Linux system. This is of interest for many embedded developers, because for many products customers expect to be able to use them very soon after system startup.

Technology/Project Pages

The following are individual pages with information about various technologies relevant to improving boot-up time for Linux. Some of these describe local patches available on this site. Others point to projects or patches maintained elsewhere.

Measuring Boot-up Time

Technologies and Techniques for Reducing Boot-up Time

  1. use of mmap vs. read
  2. control over page mapping characteristics.

Information

  • Boot-up Time Definition Of Terms - definitions of terms used by the CELF Bootup Time working group
  • Kernel Instrumentation - lists some known kernel instrumentation tools. These are of interest for measuring kernel startup time.
  • Filesystem Information - information about boot-up times with various file systems
  • Alert.gif in progress - Boot-up Time Reduction Howto - this is a project to catalog existing boot-up time reduction techniques. Work on this project is under way. The wiki will serve as the primary repository of information gathered for this project.
  • Alert.gifno content yet - Boot-up Time Delay Taxonomy - list of delays categorized by boot phase, type and magnitude

Case Studies

Additional Projects/Mailing Lists/Resources

Kexec

  • Kexec is a system which allows a system to be rebooted without going through BIOS. That is, a Linux kernel can directly boot into another Linux kernel, without going through firmware. See the white paper at: kexec.pdf

Others

  • bootspash.org - technology to put up a splash screen early in boot sequence
  • Gentoo Splashscreen - newer technology to put a splash screen early in the boot sequence
  • FSMLabs Fastboot - press release by FSMLabs about fast booting of their product. Is any of this published?
  • Bootchart - a tool for performance analysis and visualization of the Linux boot process. Resource utilization and process information are collected during the user-space portion of the boot process and are later rendered in a PNG, SVG or EPS encoded chart.