linux-kernel - Re: [PATCH perf/core v9 00/16] perf-probe --cache and SDT support

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Date:	Tue, 31 May 2016 22:00:27 +0530
From:	Hemant Kumar <hemant@...ux.vnet.ibm.com>
To:	Arnaldo Carvalho de Melo <acme@...nel.org>,
	Masami Hiramatsu <mhiramat@...nel.org>
CC:	Arnaldo Carvalho de Melo <arnaldo.melo@...il.com>,
	linux-kernel@...r.kernel.org, Namhyung Kim <namhyung@...nel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...hat.com>,
	Ananth N Mavinakayanahalli <ananth@...ux.vnet.ibm.com>,
	Brendan Gregg <brendan.d.gregg@...il.com>
Subject: Re: [PATCH perf/core v9 00/16] perf-probe --cache and SDT support



On 05/31/2016 07:09 PM, Arnaldo Carvalho de Melo wrote:
> Em Tue, May 31, 2016 at 05:00:16PM +0900, Masami Hiramatsu escreveu:
>> On Mon, 30 May 2016 13:30:53 -0300
>> Arnaldo Carvalho de Melo <acme@...nel.org> wrote:
>>
>>> Em Mon, May 30, 2016 at 01:22:52PM -0300, Arnaldo Carvalho de Melo escreveu:
>>>> Em Sun, May 29, 2016 at 12:15:01AM +0900, Masami Hiramatsu escreveu:
>>>>> Hi,
>>>>>
>>>>> Here is the 9th version of the patchset for probe-cache and
>>>>> initial SDT support.
>>>> Ok, for completeness sake: Where does one learn more about "SDT", I
>>>> couldn't find a description of this in this patchkit, /me goes googling
>>>> around...
>>> https://sourceware.org/gdb/onlinedocs/gdb/Static-Probe-Points.html
>>>
>>> Some lifting of this text, giving credit and checking whatever license
>>> it is under would help, I think.
>> Hmm, would you mean we'd better add links(urls) in Documentation/perf-probe.txt?
> I mean we should describe the feature that is being implemented, so that
> interested parties can have a better handle at testing it :-)
>
> So, yes, adding links to Documentation/perf-probe.txt is part of that.

Cool.
This is precisely what I was suggesting in the last patchset. A more
detailed explanation (including some good examples) of the feature added
to documentation will help all.

>>> Mentioning some userland components that have such "Statically Defined
>>> Tracing" markers would also help testers to try it with this patchkit, I
>>> saw just one or two examples here, IIRC with libc and libstdc++.
>> Yeah, and it depends on the binary which your distro provides.
>> Fotunately, Redhat provided binaries usually enables SDTs :)

Yeah.

>> As you can see the below page, we can add a testcase for sdt in
>> perftool itself (this also requires sdt.h provided by systemtap-devel)
>> https://sourceware.org/systemtap/wiki/AddingUserSpaceProbingToApps
> Cool, having it tested in 'perf test' will certainly help in merging
> this and keeping it working over time, when we touch code that is used
> by SDT support.

+1

> - Arnaldo
>
>> Then, user can run tests to ensure it.
>>
>> Thank you!
>>
>>> - Arnaldo
>>>   
>>>> - Arnaldo
>>>>   
>>>>> The previous version is here; https://lkml.org/lkml/2016/5/14/107
>>>>>
>>>>> This version just fixes 2 points according to Hemant's comment,
>>>>> and split out the filename__readable() patch.

Thanks for working on those Masami.

For the patches not already picked up by Arnaldo,
Acked-by: Hemant Kumar <hemant@...ux.vnet.ibm.com>

>>>>> Changes in v9:
>>>>>    - [1/16,2/16] split out the filename__readable()
>>>>>    - [7/16] Fix to show which event is deleted.
>>>>>    - [12/16] Update list_usage to show sdt option.
>>>>>
>>>>> Thank you,
>>>>>
>>>>> ---
>>>>>
>>>>> Hemant Kumar (1):
>>>>>        perf/sdt: ELF support for SDT
>>>>>
>>>>> Masami Hiramatsu (15):
>>>>>        perf-symbol: Introduce filename__readable to check readability
>>>>>        perf symbol: Cleanup the code flow of dso__find_kallsyms
>>>>>        perf-buildid-cache: Use path/to/bin/buildid/elf instead of path/to/bin/buildid
>>>>>        perf probe: Add --cache option to cache the probe definitions
>>>>>        perf probe: Use cache entry if possible
>>>>>        perf probe: Show all cached probes
>>>>>        perf probe: Remove caches when --cache is given
>>>>>        perf probe: Add group name support
>>>>>        perf buildid-cache: Scan and import user SDT events to probe cache
>>>>>        perf probe: Accept %sdt and %cached event name
>>>>>        perf-list: Show SDT and pre-cached events
>>>>>        perf-list: Skip SDTs placed in invalid binaries
>>>>>        perf probe: Allow wildcard for cached events
>>>>>        perf probe: Support @BUILDID or @FILE suffix for SDT events
>>>>>        perf probe: Support a special SDT probe format
>>>>>
>>>>>
>>>>>   tools/perf/Documentation/perf-probe.txt |   26 +-
>>>>>   tools/perf/builtin-list.c               |    6
>>>>>   tools/perf/builtin-probe.c              |   30 ++
>>>>>   tools/perf/util/build-id.c              |  295 ++++++++++++++++--
>>>>>   tools/perf/util/build-id.h              |    8
>>>>>   tools/perf/util/dso.h                   |    5
>>>>>   tools/perf/util/parse-events.c          |   83 +++++
>>>>>   tools/perf/util/parse-events.h          |    2
>>>>>   tools/perf/util/probe-event.c           |  492 +++++++++++++++++++++++++++---
>>>>>   tools/perf/util/probe-event.h           |    7
>>>>>   tools/perf/util/probe-file.c            |  504 +++++++++++++++++++++++++++++++
>>>>>   tools/perf/util/probe-file.h            |   41 +++
>>>>>   tools/perf/util/symbol-elf.c            |  252 ++++++++++++++++
>>>>>   tools/perf/util/symbol.c                |   71 ++--
>>>>>   tools/perf/util/symbol.h                |   22 +
>>>>>   15 files changed, 1712 insertions(+), 132 deletions(-)
>>>>>
>>>>> --
>>>>> Masami Hiramatsu
>>
>> -- 
>> Masami Hiramatsu <mhiramat@...nel.org>

-- 
Thanks,
Hemant Kumar