Re: [PATCH 2/2] ftrace: add stack trace to function tracer

[Ingo Molnar]

* Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:

> From: Steven Rostedt <srostedt@xxxxxxxxxx>
> 
> Impact: new feature to stack trace any function
> 
> Chris Mason asked about being able to pick and choose a function
> and get a stack trace from it. This feature enables his request.
> 
>  # echo io_schedule > /debug/tracing/set_ftrace_filter
>  # echo function > /debug/tracing/current_tracer
>  # echo func_stack_trace > /debug/tracing/trace_options
> 
> Produces the following in /debug/tracing/trace:
> 
>        kjournald-702   [001]   135.673060: io_schedule <-sync_buffer
>        kjournald-702   [002]   135.673671:
>  <= sync_buffer
>  <= __wait_on_bit
>  <= out_of_line_wait_on_bit
>  <= __wait_on_buffer
>  <= sync_dirty_buffer
>  <= journal_commit_transaction
>  <= kjournald

neat!

	Ingo
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