Bootgraph.py

bootgraph.py is a tool for gathering and presenting information about the kernel boot time.

It is available in the upstream kernel here: https://github.com/torvalds/linux/blob/master/tools/power/pm-graph/bootgraph.py

The tool can gather data from the dmesg output on an existing system, or be used to set up the command line and reboot the system for gathering data on a subsequent boot.

It requires the initcall_debug option to be used on the kernel command line. However, it can also configure and read ftrace data (either the initcall tracer or function tracer) for more detailed presentation of data about the system.

It outputs results in html format.

There is a man page for the program is here: https://github.com/torvalds/linux/blob/master/tools/power/pm-graph/bootgraph.8