Re: [PATCH 2/2] tracing/function-return-tracer: Call prepare_ftrace_return by registers

[Ingo Molnar <mingo@elte.hu>]

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

> 2008/11/13 Ingo Molnar <mingo@elte.hu>:
> > hm, function-exit is a quite bad name i think that tells nothing to
> > the user. I like "function-cost tracer" because that tells the user
> > what it's all about in the end.
> >
> > Or perhaps we could name it the "callgraph" tracer? (as opposed to the
> > simpler function tracer which traces function entries) Note that we
> > could use the output to build function call coverage graphs.
> 
> But you can build a call graph with the function tracer, that what 
> does the script draw_trace.py in a bit loosely way for example.

yes, but not reliably so - there's no guaranteed callgraph structure. 
With entry tracing we have entry+parent events, but especially across 
longer callchains there's no truly guaranteed way to preserve the full 
graph.

> IMHO, function cost measurement or call graphs are particular uses 
> that can be made of this engine. You can also use it to trace 
> function return values for example.

yes. The mockup output has place for that.

> So perhaps naming it by thinking on the purpose it could be use at 
> most would be better that its "general" or "potential" purpose. I 
> don't know...

i suggested "full-function" tracer name before, but that sounds a bit 
quirky too.

Perhaps this should be the function-tracer, and the entry tracer would 
be the function-entry tracer?

	Ingo