Re: [RFC][PATCH 0/2] tracing: Have trace_printk()s in the events/directory

From: Frederic Weisbecker
Date: Thu Nov 18 2010 - 09:03:07 EST


On Thu, Nov 18, 2010 at 08:06:36AM -0500, Steven Rostedt wrote:
> On Thu, 2010-11-18 at 13:53 +0100, Frederic Weisbecker wrote:
> > n other solution, which have been talking with Thomas yesterday, would be
> > to allow having a single fd for several perf_events at once. That would
> > solve some problems when you have hundreds of events opened (think about
> > wide tracing, or use of all individual syscalls).
>
> I would highly recommend this. One type of tracing I do all the time is
> to enable all events (over 600). I don't think that is currently
> possible with trace and/or perf.


Yep.



> Ftrace has no issue simple because it just stores all the events into a
> single buffer (per cpu though). It does not care if there's one event or
> 1000.
>
> You need to figure out how to do this as well with the function tracer.


Yeah for the function (and graph) tracers, I really plan to make it a single
event. I mean one for the function tracer and one for the function graph.
Although we may want two for the function graph tracer actually. One for
entry, one for exit.

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