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

Jiri Olsa
2018-03-21T15:38:45Z

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?

> > 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