Profiling u-Boot/Kernel boot sequence

Question

I am profiling the booting process of power PC board, what is the simplest way to profile the booting sequence ?

My first idea is to modify the u-boot/kernel code add printf/printk (using realtime device as reference) and print them on the console. However just printing them on the console may affect the time.

Any thoughts?

Regards, Robert.

Answer 1

If you think that printing may affect performance (I don't think so unless you are printing less then about 10kbytes/s) then store that data in memory and print it later.

Answer 2

There is a wonderful utility called bootchart which will give you a graphical representation of the boot process and tell you when each task started and how long it took to complete.

Check it out.

_{(source: bootchart.org)}

Answer 3

Everyone knows the best way to profile an u-boot is with sonar.