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

From: Frederic Weisbecker
Date: Fri Sep 11 2009 - 10:55:37 EST


On Fri, Sep 11, 2009 at 09:54:55AM -0400, Steven Rostedt wrote:
> From: Steven Rostedt <srostedt@xxxxxxxxxx>
>
> 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@xxxxxxxxxxx>


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...


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