Messages in this thread |  | | | Date | Mon, 22 Feb 2010 19:17:08 +0100 | | From | Frederic Weisbecker <> | | Subject | Re: [PATCH 1/1] ftrace - add support for tracing_thresh to function_graph tracer |
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On Mon, Feb 22, 2010 at 09:57:43AM -0500, Steven Rostedt wrote: > On Sat, 2010-02-20 at 15:43 +0100, Frederic Weisbecker wrote: > > > > Instead of having yet another check here, may be should we > > have a dedicated stub trace_graph_entry? > > > > > > > > > @@ -254,6 +263,10 @@ static void __trace_graph_return(struct trace_array *tr, > > > if (unlikely(__this_cpu_read(per_cpu_var(ftrace_cpu_disabled)))) > > > return; > > > > > > + if (tracing_thresh && > > > + (trace->rettime - trace->calltime < tracing_thresh)) > > > + return; > > > + > > > > > > > > And perhaps we can do the same for the return handler? > > We could have a trace_graph_return_threshold that > > performs the above check and then relies on trace_graph_return. > > So you mean to register a different type of function to the graph tracer > if trace_thresh is enabled? That does sound like a better idea.
Yeah, this is going to optimize both types of tracing. And I would also like to prevent from adding new checks in the common graph tracing if possible. User's cpus and cachelines deserve better :)
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