How to profile the kernel during its initialization?

[Vladimir Murzin]

On Wed, Jul 6, 2011 at 12:47 AM, Zheng Da <zhengda1936 at gmail.com> wrote:
> Hello
>
> Can we profile the kernel during its initialization? perf is
> initialized in an early stage in start_kernel(), but it seems there
> are no command-line parameters to enable it.
> Does anyone have any ideas how to profile the kernel during its
> initialization (before user space programs start to run)? I think
> someone should have the similar problem as me, and there should be
> some solutions.
>
> Thanks,
> Da
>
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Hi Da,

Have a look at ftrace. It could be used to profile initcalls.
Just add following boot options:

initcall_debug, ftrace=initcall

More details on
http://www.omappedia.org/wiki/Installing_and_Using_Ftrace#Boot_Tracer