Re: [PATCH 0/3] tracing/function-graph-tracer: signal interrupttriggering on output

From: Ingo Molnar
Date: Sat Dec 13 2008 - 02:50:05 EST



* Frédéric Weisbecker <fweisbec@xxxxxxxxx> wrote:

> > applied to tip/tracing/function-graph-tracer, thanks Frederic!
> >
> > The output looks really nice.
> >
> > Ingo
> >
>
> Thanks :-)
>
> If anyone has other needs or suggestions about this tracer, don't
> hesitate to request it.
> I remember Peter suggested that the preempt count could be output.

that reminds me ... did you know about hardirq_count()? We could use it
to detect IRQ entries in a more generic way, instead of the section
trick?

Another thing, i just noticed that ftrace_print() is broken in certain
situations, for example a plain newline:

ftrace_printk("\n");

printed via trace_pipe will print some weirdly concatenated line:

<...>-2994 [007] 406.498986: debug_show: <...>-2994 [007] 406.498986: <...>-2994 [007] 406.498986: debug_show:

not via a separate, standalone, empty line.

Another thing: it would be nice to have a trace_option to leave out this
preamble:

<...>-2994 [007] 406.498986: debug_show: test printk

and just give this output:

test printk

i.e. some 'printk compatibility' mode. That way i could use
ftrace_printk() as a pure replacement for printk, during development.

Ingo
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