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

From: Ingo Molnar
Date: Tue Dec 10 2013 - 10:32:03 EST



* Jiri Olsa <jolsa@xxxxxxxxxx> wrote:

> On Thu, Dec 05, 2013 at 11:45:46AM +0100, Ingo Molnar wrote:
>
> SNIP
>
> > > >
> > > > 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?
> >
> > So my worry is, how widely is libudis86 available in distros? What is
> > the package name on Debian/Ubuntu for example?
>
> I did not find any.. :-\ I can see Fedora and Gentoo

That's a problem really - all perf developers who are using Ubuntu
will see the failure, without being able to do anything about it.

So maybe we need an intermediate feature-mode for such convenience
features that don't really impact measurement capabilities, those
features could be probed but failures would not be displayed in such a
highly prominent fashion.

Thanks,

Ingo
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