Re: [PATCH 2/2] perf probe: Allow user to specify address withinexecutable

From: Masami Hiramatsu
Date: Tue Dec 03 2013 - 20:22:21 EST


(2013/12/04 0:58), David Ahern wrote:
> On 12/3/13, 2:24 AM, Masami Hiramatsu wrote:
>> I don't want to make perf-probe just a wrapper of the ftrace dynamic
>> event interface, because it doesn't add any "value" for users.
>
> Sure it does -- a consistent user experience in using a single command
> (perf probe ...) for setting up userspace probes.
>
> Specifying the address directly is really on par with perf-record having
> the rNNN interface for directly passing the raw event id to the kernel.

No, since the perf interface is not directly exposed to users
the perftools need to provide such raw interface. But the dynamic
event has it on debugfs.

>>>>> In that case, you should use uprobe_events interface directly.
>>>>
>>>> How do I do that within the context of perf?
>>
>> No way, but here, you can save this script as perf-uprobe and
>> can use it for that purpose. :)
>
> I figured out what you meant by uprobe_events interface yesterday. If I
> have to go to that interface for even 1 function I would do it for all
> -- from a user perspective it is just simpler to have 1 command to setup
> probes. I would prefer that 1 command be perf-probe.

Yeah, but in that case, why you don't ask us adding sym->binding == STB_LOCAL
in filter_available_functions? :)

Thank you,

--
Masami HIRAMATSU
IT Management Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@xxxxxxxxxxx


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