Linux Bootup Time measurement.
I am trying to find out how much time a particular linux machine takes to boot up. Bootup mean to come to a prompt, that is including time taken to switch on services by init process.
Now the problem is:
1. I know the basic bootup sequence, i.e. all those setup.s to start_kernel() etc. etc. Problem comes in creating a variable that can store time through this sequence. When initially kernel start we do not have the jiffies counter so what I thought of doing is get the current time value from BIOS call:
--> I do not know is this technique right
--> I want to know the BIOS call for this or any other service which can do the same
--> Even if I create a variable and push the value into it, can I maintain it through out the booting process
2. What is the difference between jiffies, RTC, and system clock. Which among them corresponds to the hardware clock.
I have to figure out what are the bottlenecks in the system bootup process on the basis of time, and this is where the above strategy has been selected.
--> If there is any other better way, please do suggest.
Thanks in advance