Re: [PATCH][RFC 2/23]: SCST core

Frédéric Weisbecker
2008-12-13T01:25:29Z

2008/12/13 Arnaldo Carvalho de Melo <acme@redhat.com>:
> Steven, is it possible to trigger tracing for any function when a
> function in the list set up by the user is running and then stop tracing
> when it exits?
>
> - Arnaldo
>

Hi Arnaldo,

Yes it's possible with ftrace, by using the function graph tracer ( an
ftrace extension that adds the tracing on return).

To enable it just do:
echo function_graph > /debugfs/tracing/current_tracer

And to trace by choosing a particular function as the root of the call
stack, just do the things
explained on this patch:
http://git.kernel.org/?p=linux/kernel/git/mingo/linux-2.6-sched-devel.git;a=commit;h=ea4e2bc4d9f7370e57a343ccb5e7c0ad3222ec3c

And the tracing will finish after this function returns :-)