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

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Date:   Fri, 23 Mar 2018 16:17:39 +0100
From:   Jiri Olsa <jolsa@...hat.com>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:     "Jin, Yao" <yao.jin@...ux.intel.com>, jolsa@...nel.org,
        peterz@...radead.org, mingo@...hat.com,
        alexander.shishkin@...ux.intel.com, Linux-kernel@...r.kernel.org,
        ak@...ux.intel.com, kan.liang@...el.com, yao.jin@...el.com
Subject: Re: [PATCH] perf util: Display warning when perf report/annotate is
 missing some libs

On Fri, Mar 23, 2018 at 11:50:49AM -0300, Arnaldo Carvalho de Melo wrote:

SNIP

> > > I just don't like the idea that when you run perf report,
> > > or annotate it spits out lines for every missing feature
> > > 
> > > maybe we could detect missing features for given command
> > > and display line about missing features and say something
> > > like:
> > > 
> > > 'Warning: symbol,dwarf support not compiled in (for more details run perf -vv)'
> > > 
> > > or somwthing like that.. ;-)
> > > 
> > > jirka
> > > 
> > 
> > Hi Jiri,
> > 
> > I think your idea is very good!
> > 
> > I guess following it's just an example copied from perf building process,
> > right?

yes

> > 
> > $ ./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  ]
> > 
> > We can check some CFLAGS like "#ifdef HAVE_XXX" in perf code to determine if
> > some libraries are compiled in.
> > 
> > For example,
> > 
> > #ifdef HAVE_LIBNUMA_SUPPORT
> > 	printf("libnuma: [ on  ]");
> > #endif

please display also the OFF status, to mirror the build output

#ifdef HAVE_LIBNUMA_SUPPORT
	printf("libnuma: [ on  ]");
#else
	printf("libnuma: [ OFF ]");
#endif

or in some other smarter way..

> > 
> > For some features, such as "numa_num_possible_cpus", which doesn't have
> > CFLAGS variables. Maybe we can ignore them in report?
> > 
> > I'd like to upgrade my patch to support perf -vv.
> 
> Please go ahead! :-) We're all on the same page now, I think.

yes ;-)

jirka