Re: [PATCH 2/2] tracing/branch-tracer: adapt to the stat tracing API

[Frederic Weisbecker <fweisbec@gmail.com>]

On Wed, Jan 07, 2009 at 11:49:49PM -0500, Steven Rostedt wrote:
> 
> 
> On Sat, 27 Dec 2008, Frederic Weisbecker wrote:
> 
> > This patch adapts the branch tracer to the tracing API.
> > This is not really for inclusion but more likely a proof of concept because
> > the branch tracer implements two "stat tracing" that were split in two files.
> > 
> > So I added an option to the branch tracer: stat_all_branch.
> > If it is set, then trace_stat will output all of the branches entries stats.
> > Otherwise, it will print the annotated branches.
> > 
> > Its is a kind of quick trick, waiting for a better solution.
> > By default, the annotated branches stat are sorted by incorrect branch prediction
> > percentage.
> > 
> 
> OK, I have not had a chance to look at this code since it was sent when I 
> was on Holiday. But I do not think that the only way to see the output of 
> a histogram is to set it in the current_tracer. If I have the branch 
> tracer on, I would have to run it to see the output of the histogram.
> 
> The histogram starts recording at boot up. Although the branch tracer is 
> dependent on the histograms, the histogram is not dependent on the branch 
> tracer. This code is making the histogram dependent on the trace. It took 
> me a while to figure out how to see my histogram.
> 
> With the new patches (after the compile issue is solved) we could have a 
> register_histogram or something that would put the file in the trace_stats 
> directory. This would separate the need of coupling the tracers with the 
> histogram even when they are not coupled.
> 
> -- Steve

You're right, that's a better and more scalable idea.
Should I do it on top of the current patches (when the compile is fixed?).
That will be more easy...

Thanks.