Re: [PATCH v1 0/3] Support perf -vv

[Jin, Yao]

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