Re: Human readable output for function return tracer

Frédéric Weisbecker
2008-11-25T16:02:05Z

2008/11/25 Ingo Molnar <mingo@elte.hu>:
>
> * Ingo Molnar <mingo@elte.hu> wrote:
>
>>
>> * Ingo Molnar <mingo@elte.hu> wrote:
>>
>> > > Do you agree with "full function tracer" (since we hook now on the
>> > > two sides)?
>> >
>> > "full function tracer" sounds a bit funny and quirky. How about
>> > "function call tracer"? Versus the "function tracer" or "function
>> > entry tracer" which is the lighter variant - both in name and in
>> > overhead. So we'd have:
>> >
>> > # cat /debug/tracing/available_tracers
>> > mmiotrace wakeup irqsoff function function-call sysprof sched_switch initcall nop
>> >
>> > note how intuitive it is: "function-call" is 'more' than just the
>> > plain function-tracer. It also expresses its main property: it
>> > traces the full call, entry and exit and return code as well.
>>
>> another similar naming would be: the "function-graph" tracer.
>> function-callgraph would be too long.
>
> Steve thinks function-graph is even more expressive, so lets go with
> that instead :)
>
> it will certainly make sure there's no misunderstanding about the role
> and scope of this tracer, and it's short and expressive as well.
>
> so i'd suggest the following sed -i rules:
>
> s/FUNCTION_RET_TRACER/FUNCTION_GRAPH_TRACER/g
>
> i'd suggest to keep the ret_stack names - those are proper. (the thing
> that is used to construct the graph is the return stack)
>
> also, please do:
>
> git mv kernel/tracing/trace_functions_return.c kernel/tracing/trace_functions_graph.c
>
> and Makefile glue fixup:
>
> s/functions_return/functions_graph/g
>
> Ingo
>

Ok, and perhaps even several structures and functions.... There are
some in trace_functions_return.c, arch/x86/kernel/ftrace.c,
kernel/trace/ftrace.c
Some of them which act very close to "return hooking" should keep
their name, but for some others, I should put the graph semantics....