Re: [PATCH] perf util: Display warning when perf report/annotate is missing some libs

[Arnaldo Carvalho de Melo]

Em Wed, Mar 21, 2018 at 04:38:07PM +0100, Jiri Olsa escreveu:
> On Wed, Mar 21, 2018 at 10:11:10AM +0800, Jin, Yao wrote:
> > Hi Jiri,
> > 
> > I'm still thinking it's worth displaying the warning when perf missing some
> > libraries.
> > 
> > Somebody just told me that perf didn't work well. While after some
> > investigations, I found it's just missing some libraries when building the
> > perf.
> > 
> > But I have spent some time on getting the root cause. If with this patch, it
> > should be very easily to know that.
> 
> true.. Arnaldo, any feedback on this one?

Lemme re-read the thread...

 
> > > I just think it'd better provide some hints to user. For example,
> > > "symbol is disabled and you need to install libelf/xxx", say something
> > > like that.
> > > 
> > > But it looks the column can't contain too much information (i.e. no more
> > > space to contain the entire hints).
> > > 
> > > Any idea? Or just add this warning in verbose mode?
> > > 
> > > > also your change does not affect tui mode
> > > > 
> > > > annotation for some reason does not start at all.. could be
> > > > little more verbose ;-)
> > > > 
> > > > jirka
> > > > 
> > > 
> > > Yes, it doesn't affect tui mode.
> > > 
> > > Or we just add this warning in verbose mode?
> > > 
> > > e.g. perf report -v?
> 
> how about displaying libraries separately with -vv output,
> that would mimic the build message, like:
> 
>   $ ./perf -vv
>   perf version 4.16.rc6.g18fd48
> 
>                    dwarf: [ on  ]
>       dwarf_getlocations: [ on  ]
>                    glibc: [ on  ]
>                     gtk2: [ on  ]
>                 libaudit: [ on  ]
>                   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  ]
> 
> and perf -vvv could display the 'make VF=1' info
> 
> jirka