Re: [tip:perf/urgent] perf symbols: Allow lookups by symbol name too

[Frederic Weisbecker <fweisbec@gmail.com>]

On Tue, Dec 15, 2009 at 12:20:20AM -0200, Arnaldo Carvalho de Melo wrote:
> Em Tue, Dec 15, 2009 at 03:12:03AM +0100, Frederic Weisbecker escreveu:
> > On Sat, Dec 12, 2009 at 07:22:03AM +0000, tip-bot for Arnaldo Carvalho de Melo wrote:
> > > Looking over the vmlinux/kallsyms is common enough that I'll add a
> > > variable to the upcoming struct perf_session to avoid the need to
> > > use map_groups__find_by_name to get the main vmlinux/kallsyms map.
> > > 
> > > The above example looks on the 'variable' symtab, but it is just
> > > like that for the functions one.
> > > 
> > > Also the sort operation is done when we first use
> > > map__find_symbol_by_name, in a lazy way.
> > 
> > It would be nice to also have a kernel symbol resolution
> > helper independant of any session.
> > 
> > The problem is that I need to resolve a kernel variable symbol
> > very early, when we parse record options. We don't have any
> > session at this time so I can't retrieve the kmaps.
> 
> Humm, I don't think that is a problem, we just have to create the
> session before processing the args, after all at record time we can use
> kallsyms already.



Yeah but we need the output filename before creating it, which
we even don't have yet at this time.

May be I should just init it very early without the filename
and assign it later with a small new helper.

Another problem is that the record session is not available
from parse-events.c, may be should I create a single wide scope
record_session that would be shared among record, top and stat
so that it's available from parse-event.c


> 
> > I'm not sure what's the proper way to handle that.
> 
> What is the problem? I'm not following :-)


I think the real problem actually is that I should join
my bed.
The above questions will retrieve their trivial essence after
some sleep :)