Re: [PATCH] perf-probe: make "perf-probe -L <function>" display theabsolute path and absolute line number

From: Masami Hiramatsu
Date: Fri Jan 14 2011 - 05:33:46 EST


Hi Franck,

(2011/01/14 18:03), Franck Bui-Huu wrote:
> But if you think it should be used to hint for a probe point syntax,
> (you'll probably use copy & paste since it uses absolute path name),

Not only for copy&paste, but also for avoiding confusion.
Please imagine that user see this output.

</usr/src/debug/kernel-2.6.35.fc14/linux-2.6.35.x86_64/kernel/sched.c:3823>
10 rq = cpu_rq(cpu);
11 rcu_note_context_switch(cpu);

"Why the definition line number and starting line number are different?"
"How I can put a probe? sched.c:3823 ... + 10??"
"Or, it's just buggy! report it!"

I don't want this.

> then this patch is wrong.

Yeah, but just a _bit_. Basically, I agree with your idea of showing
actual path of the function, because, indeed, perf-probe just shows
the first one even if there are many same-name functions.

So, here, I had suggested an enhancement idea;

$ perf probe -L schedule:0-1
<schedule@/usr/src/debug/kernel-2.6.35.fc14/linux-2.6.35.x86_64/kernel/sched.c:0>
0 asmlinkage void __sched schedule(void)
1 {

This is acceptable, because it shows which function you see and
it also gives you how you can specify a probe point on a function
line.

Thank you,

--
Masami HIRAMATSU
2nd Dept. Linux Technology Center
Hitachi, Ltd., Systems Development Laboratory
E-mail: masami.hiramatsu.pt@xxxxxxxxxxx
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/