tracing in Linux

Tracing: no shortage of options

http://lwn.net/Articles/291091/

Linux start-up process

http://www.cromwell-intl.com/unix/linux-boot.html
http://luv.asn.au/overheads/linux-startup.html
http://www.yolinux.com/TUTORIALS/LinuxTutorialInitProcess.html
http://www.comptechdoc.org/os/linux/startupman/linux_surcsysinit.html