Re: [PATCH 0/4] Fixes for perf/scripting

[Tom Zanussi <tzanussi@gmail.com>]

On Mon, 2009-11-30 at 09:19 +0100, Ingo Molnar wrote:
> * Tom Zanussi <tzanussi@gmail.com> wrote:
> 
> > Tom Zanussi (4):
> >   perf trace/scripting: silence PERL_EMBED_* backtick errors
> >   perf trace/scripting: ignore shadowed variable warning for
> >     perf-trace-perl.c
> >   perf trace/scripting: fix Perl common_* access functions
> >   perf trace/scripting: Add Fedora libperl install note to doc
> > 
> >  tools/perf/Makefile                                |    6 ++--
> >  tools/perf/scripts/perl/Perf-Trace-Util/Context.c  |   30 ++++++++++----------
> >  tools/perf/scripts/perl/Perf-Trace-Util/Context.xs |    6 ++--
> >  tools/perf/scripts/perl/Perf-Trace-Util/README     |    4 +-
> >  tools/perf/util/trace-event-perl.c                 |   10 ++++--
> >  tools/perf/util/trace-event-perl.h                 |    6 ++--
> >  6 files changed, 32 insertions(+), 30 deletions(-)
> 
> Applied, thanks Tom!
> 
> I tried a few simple things and it worked fine, so i put it into the 
> permanent perf/scripting branch. I think this looks like a nice feature: 
> a perfect fit to do rapid prototyping of tracing applets. (or just to 
> use it for ad-hoc, programming based analysis of tracing data)
> 

Great, thanks!

I agree that usability is key and could use some more work - I'll submit
some more patches addressing that soon...

Thanks,

Tom

> There's a few odd ends to 'perf trace' usability we need to fix before 
> this can be merged into perf/core. For example if libperl isnt 
> installed, 'perf trace' emits this warning:
> 
>  Perl scripting not supported.  Install libperl and rebuild perf to 
>  enable it.  e.g. apt-get install libperl-dev (ubuntu), yum install 
>  perl-ExtUtils-Embed (Fedora), etc.
> 
> We should only emit that if -g or -s is used - it's a nuisance in the 
> other cases. Most distributions dont have libperl installed by default.
> 
> Also, a few simple examples and some heads-up about the power of 
> scripting should be put into Documentation/perf-trace.txt as well. 
> Something minimal - and it can include a Perl example as well. Some 
> practical version of perl/Perf-Trace-Util/README or so. We want curious 
> people who know Perl and try 'perf trace --help' to have some minimal 
> entry vector into this space.
> 
> A third question is - right now we install the sample Perl scripts on 
> 'make install', but there's no mechanism to see the scripts that are 
> available. 'perf trace -l/--list' might be useful?
> 
> I.e. the whole pathway of random perf users coming in and starting to 
> use the script engine 'spontaneusly' and 'intuitively' is not yet 
> thought through - the capabilities are hidden too much.
> 
> Thanks,
> 
> 	Ingo