Messages in this thread | | | Date | Mon, 24 Nov 2008 15:39:45 +0100 | From | "Frédéric Weisbecker" <> | Subject | Human readable output for function return tracer |
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Hi,
I'm planning to apply an idea proposed by Ingo to make the output on the function return tracer more "eyes-parsable". The idea consists on a trace which has flow similar to C code:
func1() { func2() { func3() { } } func4() { } }
(With time of execution added on closing braces).
The problem is that the traces arrive in the reverse order, according to the fact that functions are traced on return. The order corresponding to the above example would be as the following:
func3, func2, func4, func1
Oh and we have the parent in a return trace, so we would actually have:
func2->func3 func1->func4 .... ->func1
This trace flow doesn't make the things easy to produce our C like code.
So I found only one solution which have both pros and cons. I could send a "pre-trace" to the ring-buffer to signal that function x with depth y is beeing called (when we enter the function).
The pros:
_ It will be easy to draw our C 'like trace, without any special pre-output work. _ The name could be definetly full-function-tracer with this new pre-trace :-) _ Automatic trace parsing, tree of calls building will be more easy....
The cons:
_ The function-return-tracer slows down the system. It will be worst with a new insertion in the ring-buffer. But if it is mostly used with dynamic ftrace and a good set of filtered functions, I don't think that will be an issue.
If you think about an other solution, don't hesitate to tell me :-) Thanks....
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