[ltt-dev] [PATCH] tracepoints: Generate Module.tracepoints file

Frank Ch. Eigler fche at redhat.com
Tue Sep 23 12:09:42 EDT 2008

Hi -

On Mon, Sep 22, 2008 at 10:53:32PM -0400, Mathieu Desnoyers wrote:
> * Frank Ch. Eigler (fche at redhat.com) wrote:
> > Jan Blunck <jblunck at suse.de> writes:
> > 
> > > This adds support to generate the Module.tracepoints file by modpost. This
> > > can be read by tools like SystemTap very similar to the Module.markers file.
> > > [...]
> > 
> > For systemtap, the problem with tracepoints is not so much knowing the
> > list of them, but knowing how to dynamically interface to them.  In
> > particular, the parameter type signatures are a problem because they
> > can be general C type decls, which are hard just to parse.
> Why would you want to deal with tracepoints dynamically ? [...]

Because I disprefer tracepoint-to-marker conversion modules.  Even if
you imagine hand-coded tracepoint consumer code sitting inside
systemtap, then the "Module.tracepoints" file is not needed anyway.

> And remember, tracepoints are meant to be few, well thought and not to
> cange too often once things settle down.
> OTOH, markers can be used as temporary debugging statements, which makes
> it understandable to follow their changes dynamically.

I hope this peculiar dichotomy can be redressed as a part of the
current lkml "unified tracing buffer" discussion.

- FChE

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