Re: [RFC 00/14] perf tools: Introduce new 'ftrace' command
Date: Wed Apr 24 2013 - 07:16:49 EST
On 2013/4/24 17:27, Namhyung Kim wrote:
> Hi Steve,
> On Tue, 23 Apr 2013 11:58:01 -0400, Steven Rostedt wrote:
>> On Tue, 2013-04-23 at 17:30 +0900, Namhyung Kim wrote:
>>> This patchset implements a front-end tool for kernel's ftrace. It
>>> uses function_graph tracer by default and normal function tracer is
>>> also supported. (Of course you need to enable those tracers in your
>>> kernel first.)
>>> NOTE: It's in very early stage, so may contain many rough edges.
>> Very nice Namhyung, thanks for doing this. I did a quick run through of
>> the patches and I have no complaints about them. I'm not sure how the
>> others will feel about it.
>> Also, have you given thought on how to execute both ftrace and the pmu
>> counters? That is, to get a way to interleave the data?
> I didn't think about it yet. I just thought enabling event tracing in
> ftrace and get the data along with the function tracing. I'm not sure
> how they interfere each other when enabled at the same time.
> If that's not a valid concern, I think it's doable.
There have ftrace:function event in tracing infrastructure, that event works in perf,
but I'm not sure if it could enhance to showing function graph as this patchset did.
perf record -e ftrace:function ls > /dev/null
>> I added a 'perf' clock to ftrace. I didn't see that being checked,
>> although I didn't look too hard. If possible, you can use that, as well
>> as the multi-buffers that are coming in 3.10.
> Will look at it later.
>> I would also like to add a system call to allow you to get to the ftrace
>> data without the need for debugfs. I'm not sure if we should piggy back
>> on the perf system call, or add a new one. I'm thinking we should add a
>> new one so that it doesn't get too confusing.
> Could you elaborate on it more? I cannot see how it'll look like..
>> Hope others have comments,
> Thanks for your kind review.
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