scripts/bootgraph.pl

dmesg | perl scripts/bootgraph.pl > output.svg

bootgraph.pl turns a dmesg output into a SVG graphic that shows which functions take how much time. You can view SVG graphics with various programs, including Inkscape, The Gimp and Firefox.

For this script to work, the kernel needs to be compiled with CONFIG_PRINTK_TIME, and with initcall_debug passed on the kernel command line.