Is it possible to use ftrace to measure secondary CPU bootup time

[Huang\, Ying]

Hi, Steven,

We are working on parallelizing secondary CPU bootup.   So we need to
measure the bootup time of secondary CPU, that is, measure time spent in
smp_init() and its callees.  But we found that ftrace now doesn't
support measure time spent in smp_init() because it is called too early
(before core_initcall()?).  So, do you think it is possible to use
ftrace to measure secondary CPU bootup time?

Thanks,
Huang, Ying