Re: [GIT PULL 00/12] perf/core improvements and fixes

[Ingo Molnar <mingo@kernel.org>]

* Jiri Olsa <jolsa@redhat.com> wrote:

> On Thu, Feb 27, 2014 at 01:30:52PM +0100, Ingo Molnar wrote:
> > 
> > * Jiri Olsa <jolsa@redhat.com> wrote:
> > 
> > > On Thu, Feb 27, 2014 at 12:46:58PM +0100, Ingo Molnar wrote:
> > > > 
> > > > * Arnaldo Carvalho de Melo <acme@infradead.org> wrote:
> > > > 
> > > > > From: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
> > > > > 
> 
> SNIP
> 
> > > > Pulled, thanks a lot Arnaldo!
> > > > 
> > > > Btw., the build output looks weird now - on a system that used to pass 
> > > > all feature tests there's this output:
> > > > 
> > > >   BUILD:   Doing 'make -j12' parallel build
> > > > config/Makefile:288: No libdw DWARF unwind found, Please install 
> > > > elfutils-devel/libdw-dev >= 0.158 and/or set LIBDW_DIR
> > > > 
> > > > Auto-detecting system features:
> > > > ...                         dwarf: [ on  ]
> > > > ...                         glibc: [ on  ]
> > > > ...                          gtk2: [ on  ]
> > > > ...                      libaudit: [ on  ]
> > > > ...                        libbfd: [ on  ]
> > > > ...                        libelf: [ on  ]
> > > > ...                       libnuma: [ on  ]
> > > > ...                       libperl: [ on  ]
> > > > ...                     libpython: [ on  ]
> > > > ...                      libslang: [ on  ]
> > > > ...                     libunwind: [ on  ]
> > > > ...            libdw-dwarf-unwind: [ OFF ]
> > > > ...     DWARF post unwind library: libunwind
> > > > 
> > > > but:
> > > > 
> > > >    Package elfutils-devel-0.156-5.fc19.x86_64 already installed and latest version
> > > > 
> > > > Also, the information content of this line is unclear to me:
> > > > 
> > > > ...     DWARF post unwind library: libunwind
> > > > 
> > > > 
> > > > what does that line want to tell?
> > > 
> > > this tells what DWARF unwind library is compiled
> > > in.. 'libunwind' in this case
> > 
> > So my (stylistic) complaint is that it's really reading weird in a 
> > table generated with the following purpose:
> > 
> >       Auto-detecting system features:
> > 
> > Also, we already know that libunwind is present, because just in the 
> > line before it, it says:
> > 
> >     ...                     libunwind: [ on  ]
> > 
> > So it's doubly confusing. How about not displaying that line at all? 
> > Is there a strong reason to not keep 'OFF' messages on a single line?
> 
> well, on/OFF lines are only about detecting libs
> 
> this line:
> 'DWARF post unwind library: libunwind'
> 
> is about telling which one goes in.. could be you have both
> libraries detected and need to choose one or keep default

Okay - but that is not at all clear from the output.

Thanks,

	Ingo