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SubjectRe: [PATCH v1 0/3] Support perf -vv
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On 3/26/2018 5:07 PM, Jiri Olsa wrote:
> On Mon, Mar 26, 2018 at 02:00:31AM -0700, Andi Kleen wrote:
>> On Tue, Mar 27, 2018 at 12:07:01AM +0800, Jin Yao wrote:
>>> We keep having bug reports that when users build perf on their own,
>>> but they don't install some needed libraries such as libelf,
>>> libbfd/libibery.
>>>
>>> The perf can build, but it is missing important functionality. And
>>> users may complain that perf has issue or bug.
>>>
>>> This patch-set support 'perf -vv' which will print the compiled-in
>>> status of libraries. Once users think perf missing some functionality,
>>> it should be very easy for them to check the libraries status.
>>
>> I don't think this solves the problem. How should the user know
>> that they need to run perf -vv. Also normal users don't know
>> that libelf is needed for symbols for example.
>>
>> We need a warning that is visible together with the symbols
>> and that clearly describes the problem.
>
> IIRC we decided to go *with* the message in the perf report
> or other affected command that would suggest to run 'perf -vv'
> for more details
>
> jirka
>

Hi Andi,

For how the users know they should run 'perf -vv', as the discussion
with Jiri and Arnaldo, the message will be displayed if necessary when
users perform perf report or other perf commands. That could be
implemented in a follow-up patch (not in this patch-set).

For let user know what the library they need, maybe we can add more
information in 'perf -vv', for example, add something like,

"Please install libelf-dev, libelf-devel or elfutils-libelf-devel before
building perf"

Thanks
Jin Yao

>>
>> -Andi
>>
>>>
>>> For example:
>>>
>>> $ ./perf -vv
>>> perf version 4.13.rc5.g9b7a81b
>>> dwarf: [ on ]
>>> dwarf_getlocations: [ on ]
>>> glibc: [ on ]
>>> gtk2: [ on ]
>>> libaudit: [ off ]
>>> libbfd: [ on ]
>>> libelf: [ on ]
>>> libnuma: [ on ]
>>> numa_num_possible_cpus: [ on ]
>>> libperl: [ on ]
>>> libpython: [ on ]
>>> libslang: [ on ]
>>> libcrypto: [ on ]
>>> libunwind: [ on ]
>>> libdw-dwarf-unwind: [ on ]
>>> zlib: [ on ]
>>> lzma: [ on ]
>>> get_cpuid: [ on ]
>>> bpf: [ on ]
>>>
>>> Jin Yao (3):
>>> perf config: Add -DNO_GLIBC to CFLAGS
>>> perf version: Print the status of compiled-in libraries
>>> perf: Support perf -vv
>>>
>>> tools/perf/Makefile.config | 2 +
>>> tools/perf/builtin-version.c | 125 +++++++++++++++++++++++++++++++++++++++++++
>>> tools/perf/builtin.h | 1 +
>>> tools/perf/perf.c | 6 +++
>>> 4 files changed, 134 insertions(+)
>>>
>>> --
>>> 2.7.4
>>>

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