Re: ftrace and debugfs weird interaction
From: Steven Rostedt
Date: Mon Apr 28 2008 - 15:27:43 EST
5BOn Mon, 28 Apr 2008, Ingo Molnar wrote:
>
> * Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxx> wrote:
>
> > Hi,
> >
> > When trying to figure out what was going on with the sched tracer
> > "tracing_enabled" file (sched-devel.git tree), I fell on this strange
> > behavior :
> >
> > echo 1>tracing_enabled seems _not_ to send 1 to the tracing_ctrl_write
It should actually send "1" and not 1 (and technically "1\n") ;-)
> > callback. However, sending garbage, e.g. echo s> tracing_enabled,
> > correctly sends the 's' character down the chain. echo 0>tracing_enabled
> > sometimes results in the callback not even being called.
I haven't seen this. Perhaps I'm confused about what you are seeing.
> >
> > The debugfs file has been created with
> >
> > entry = debugfs_create_file("tracing_enabled", 0644, d_tracer,
> > &global_trace, &tracing_ctrl_fops);
> > if (!entry)
> > pr_warning("Could not create debugfs 'tracing_enabled' entry\n");
> >
> > I wonder what kind of weird debugfs interaction we might have here ?
This looks normal to me. Could you provide a bit more detail to what you
are doing, what the results are, and what you expect the restults to be?
>
> hm. Cc:-ed more ftrace developers.
Thanks,
-- Steve
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