Methods to Improve Bootup Time in Linux

Users of consumer electronics product expect their devices to be available for use very soon after being turned on. Configurations of Linux for desktop and server markets exhibit boot times in the range of 20 seconds to a few minutes, which is unacceptable for many consumer products.

This paper presents several techniques for reducing the bootup time of the Linux kernel, including Execute-In-Place (XIP), avoidance of calibrate_delay(), reduced probing by certain drivers and subsystems, and parallelized driver initialization. Using a variety of techniques, the Linux kernel can be booted on embedded hardware in under 500 milliseconds. Current efforts and future directions of work to improve bootup time are described. This work is being conducted by the CE Linux forum.