Re: [PATCH 28/28] perf tools: Add udis86 disassembler feature check

[Jiri Olsa <jolsa@redhat.com>]

On Thu, Dec 05, 2013 at 10:25:02AM +0100, Ingo Molnar wrote:
> 
> * Jiri Olsa <jolsa@redhat.com> wrote:
> 
> > On Wed, Dec 04, 2013 at 03:50:24PM -0300, Arnaldo Carvalho de Melo wrote:
> > > Em Tue, Dec 03, 2013 at 02:09:42PM +0100, Jiri Olsa escreveu:
> > > > Adding udis86 disassembler feature check which support
> > > > is needed for kvm:kvm_emulate_insn tracepoint.
> > > >  
> > > > +$(call feature_check,udis86)
> > > > +ifeq ($(feature-udis86), 1)
> > > > +  LIBTRACEEVENT_CFLAGS += -DHAVE_UDIS86
> > > > +  EXTLIBS += -ludis86
> > > > +else
> > > > +  msg := $(warning No udis86 support.);
> > > > +endif
> > > 
> > > That is really an incomplete message, what package should I install?
> > > Perhaps we should add this there then:
> > > 
> > > http://bit.ly/1hyrN52
> > 
> > nice :-)
> > 
> > > 
> > > Wow, that was easy, but yeah, could be made easier 8-) ;-P
> > 
> > so something like:
> > No udis86 found. Please install udis86-devel.
> > 
> > or:
> > No udis86 found, disabling kvm tracepoints instruction disassembly. Please install udis86-devel.
> 
> 1)
> 
> So, the first problem I can see is in the output:
> 
> Auto-detecting system features:
> ...                     backtrace: [ on  ]
> ...                         dwarf: [ on  ]
> ...                fortify-source: [ on  ]
> ...                         glibc: [ on  ]
> ...                          gtk2: [ on  ]
> ...                  gtk2-infobar: [ on  ]
> ...                      libaudit: [ on  ]
> ...                        libbfd: [ on  ]
> ...                        libelf: [ on  ]
> ...             libelf-getphdrnum: [ on  ]
> ...                   libelf-mmap: [ on  ]
> ...                       libnuma: [ on  ]
> ...                       libperl: [ on  ]
> ...                     libpython: [ on  ]
> ...             libpython-version: [ on  ]
> ...                      libslang: [ on  ]
> ...                     libunwind: [ on  ]
> ...                       on-exit: [ on  ]
> ...            stackprotector-all: [ on  ]
> ...                       timerfd: [ on  ]
> 
> config/Makefile:421: No udis86 support.
> 
> such a 'no XYZ support' message should only occur if a feature test 
> failed. _If_ we decide that 'udis86' support is required for a full 
> perf build then there should be a new line saying something like:
> 
> ...                        udis86: [ OFF ]

hum, just sent v4 that added udis86 into above list ;-)

So.. do we consider 'full perf build' to be build with all
possible libraries linked in?

then we need to cleanup above list and remove:
  on-exit
  timerfd
  libelf-getphdrnum
  libelf-mmap
  stackprotector-all
  fortify-source
  backtrace

or maybe have verbose list where we display everything (for V=1 ?)
and by default display only library checks

> 
> 2)
> 
> The other problem I see is that I think we should start adding the 
> install-suggestions to the feature-check lines themselves.
> 
> On .deb based systems it should say something like:
> 
> ...                       on-exit: [ on  ]
> ...            stackprotector-all: [ on  ]
> ...                       timerfd: [ on  ]
> ...                        udis86: [ OFF ]    # apt-get install udis86-dev
> 
> On RPM based systems it should say something like:
> 
> ...                       on-exit: [ on  ]
> ...            stackprotector-all: [ on  ]
> ...                       timerfd: [ on  ]
> ...                        udis86: [ OFF ]    # yum install udis86-devel
> 
> Or so. I think we can maintain package suggestion strings for these 
> two main distro variants.
> 
> The package install strings should probably be maintained together 
> with the list of feature names in some table/list format. Such lookup 
> tables can be implemented either in Make via:
> 
>   http://www.gnu.org/savannah-checkouts/gnu/make/manual/html_node/Computed-Names.html
> 
> Or via a shell command in the makefile, using Bash associative arrays 
> or such.

sounds good

jirka