Re: [PATCH 3/3] tracing: add latency format to function_graph tracer

[Frederic Weisbecker <fweisbec@gmail.com>]

On Fri, Sep 11, 2009 at 09:54:55AM -0400, Steven Rostedt wrote:
> From: Steven Rostedt <srostedt@redhat.com>
> 
> While debugging something with the function_graph tracer, I found the
> need to see the preempt count of the traces. Unfortunately, since
> the function graph tracer has its own output formatting, it does not
> honor the latency-format option.
> 
> This patch makes the function_graph tracer honor the latency-format
> option, but still keeps control of the output. But now we have the
> same details that the latency-format supplies.
> 
>  # tracer: function_graph
>  #
>  #      _-----=> irqs-off
>  #     / _----=> need-resched
>  #    | / _---=> hardirq/softirq
>  #    || / _--=> preempt-depth
>  #    ||| /
>  #    ||||
>  # CPU||||  DURATION                  FUNCTION CALLS
>  # |  ||||   |   |                     |   |   |   |
>   3)  d..1  1.333 us    |        idle_cpu();
>   3)  d.h1              |        tick_check_idle() {
>   3)  d.h1  0.550 us    |          tick_check_oneshot_broadcast();
>   3)  d.h1              |          tick_nohz_stop_idle() {
>   3)  d.h1              |            ktime_get() {
>   3)  d.h1              |              ktime_get_ts() {
> 
> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>


Great!! Thanks a lot!
That was in my todo list :-)

Oh, BTW, what would you think about addding the current->lock_depth
in the latency format? That may help debug the bkl...