Re: [RFC] tracefs

Ingo Molnar
2009-10-23T10:30:02Z

* Frederic Weisbecker <fweisbec@gmail.com> wrote:

> On Fri, Oct 23, 2009 at 07:32:37AM +0200, Ingo Molnar wrote:
> >
> > * Greg KH <greg@kroah.com> wrote:
> >
> > > Hi all,
> > >
> > > At LinuxCon this year, Steven and I talked about moving the
> > > debugfs usage in the tracing core to a stand-alone filesystem to
> > > give the ability to start to lock down the api so that people an
> > > count on what is going on in the tracing userspace interface.
> >
> > What we want to move out initially (and i talked to Steve and
> > Frederic about that a few weeks ago) is the event description bits -
> > the format stuff in /debug/tracing/events/ - but definitely not all
> > the other, rather messy and ad-hoc APIs.
> >
> > _No way_ do we want to tie down the pretty-printing ftrace details
> > as an ABI. We promised that when ftrace went upstream and all the
> > details are way too messy to be exposed in an ABI alike matter (and
> > yes, consider this a NAK Steve ;-).
> >
> > We want a _very_ careful exporting of certain pieces of information
> > that helps syscall-exposed perf events bits, and to improve the
> > quality of interfaces while we do that.
> >
> > Ingo
>
>
> I guess the first bits that need to be exported are the
> TRACE_EVENT_ABI. But even before that, we need to ensure we have a
> final version of the trace events description.

Yeah, exactly. Once we pin them down they'll be with us for a very long
time.

Ingo