call graphs in sprof

[Pierre Habouzit]

On Tue, Jul 03, 2007 at 05:28:57PM +0200, Pierre Habouzit wrote:
> On Tue, Jul 03, 2007 at 11:30:57AM +0530, Arvind Ayyangar wrote:
> > Thanks. i installed libc6-dbg and the call graph does give me more
> > information. But I still find symbols name <UNKNOWN> in the call
> > graphs.
> 
>   please read mails fully.
> 
> > >  It means that your libc is built without debug symbols, so that the
> > >profiler cannot know what's going on in your libc. Worse, if you're
>                                                       ^^^^^^^^^^^^^^^^
> > >using a gprof based method, it would also need your libc to be built
>    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> > >with profiling enabled, a thing that almost no distributions give.  But
>    ^^^^^^^^^^^^^^^^^^^^^^
> > >sysprof/oprofile-like tools do not need that rebuild, so use them :)

  okay someone (thanks Michael) remind me we have (Debian) a libc6-prof
for your needs. Though I still stress _again_ that sysprof or oprofile
will give you quite often better results, and do not need your library
to be built with profiling.

  Also note that profiling often disturbs the measure, because it has a
non negligible overhead.

-- 
·O·  Pierre Habouzit
··O                                                madcoder@debian.org
OOO                                                http://www.madism.org
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