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Re: [RFC PATCH v1 0/2] perf: Support for SDT markers
- From: Namhyung Kim <namhyung at kernel dot org>
- To: Hemant Kumar <hkshaw at linux dot vnet dot ibm dot com>
- Cc: Masami Hiramatsu <masami dot hiramatsu dot pt at hitachi dot com>, linux-kernel at vger dot kernel dot org, srikar at linux dot vnet dot ibm dot com, peterz at infradead dot org, oleg at redhat dot com, hegdevasant at linux dot vnet dot ibm dot com, mingo at redhat dot com, anton at redhat dot com, systemtap at sourceware dot org, aravinda at linux dot vnet dot ibm dot com, penberg at iki dot fi
- Date: Wed, 26 Feb 2014 17:18:31 +0900
- Subject: Re: [RFC PATCH v1 0/2] perf: Support for SDT markers
- Authentication-results: sourceware.org; auth=none
- References: <20140224090833 dot 7998 dot 5416 dot stgit at hemant-fedora> <530C821D dot 7000704 at hitachi dot com> <530CBD53 dot 9010605 at linux dot vnet dot ibm dot com>
Hi Masami and Hemant,
On Tue, 25 Feb 2014 21:27:07 +0530, Hemant Kumar wrote:
> On 02/25/2014 05:14 PM, Masami Hiramatsu wrote:
>> (2014/02/24 18:14), Hemant Kumar wrote:
>>> First, scan the binaries using :
>>> # perf list sdt --scan
>>>
>>> Creating a cache of SDT markers...
>>> perf sdt cache created!
>>> Use : "perf list sdt"
>>> to see the SDT markers
>> Hmm, in that case, I think you'd better introduce perf-sdt for scanning.
>> e.g.
>>
>> # perf sdt --scan app
>
> Hmm, this seems a better idea :)
>
>> then you can add app to sdt cache, without app,
>>
>> # perf sdt --scan
>>
>> will just scans all binaries on the PATH and the libraries which listed
>> by `ldconfig --print-caceh`
What should be done with the new perf sdt command? If it's only
intended to list the markers, I'd just suggest to add "perf list sdt" as
this patch did.
Plus I think it'd be better if event_glob pattern also looks for sdt
markers so that user can find out a specific markers easily, e.g.:
# perf list rtld:*
or
# perf list %rtld:*
>>
>> And perf-list shows only the SDTs in the cache.
>
> Well, what will be better? perf-list or perf-sdt or perf-list sdt??
> If perf-list, then wouldn't it be a huge list!!
The output of perf list is already a huge list and we paginate it. So I
don't think it's gonna be a problem. :)
>>> - Add support to probe these SDT markers and integrate with a previous patch
>>> (support to perf to probe SDT markers) posted in lkml.
>>> https://lkml.org/lkml/2013/10/23/10
>> Yeah, but I think we'd better choose another way to integrate it.
>> Since SDT is like markers(static events), setting each of them via perf-probe is
>> not intuitive. :) I'd like to use it as an event, e.g.
>>
>> # perf top -e "%libgcc:unwind"
>>
>> And perf top internally calls perf-probe to add new uprobe event, and
>> clean the new event at exit.
>
> Yeah! Right :) Makes sense.
>
> Will implement the suggestions in the next version asap!
That would be great!
Thanks,
Namhyung