[Devel] Re: [PATCH 3/6] perf: add ability to record event period

[Arnaldo Carvalho de Melo]

Em Fri, Dec 16, 2011 at 11:13:07AM +0400, Andrew Vagin escreveu:
> Hi Arnaldo,
> 
> Could you review and commit this patch. It's quite common
> functionality, which allow to get events more effectively and to
> avoid losing events.
> 
> All other patches may be postponed, because Arun Sharma wants to
> suggest your version of "Profiling sleep times".

It would help if you provided a more detailed patch description, this
one came with just a title :-\

You started to ellaborate above when stating that "which allows to get
events more effectively", could you please expand on that and mention
that it will be used by the following patches that will implement
feature X, etc?

I get that Arun is in agreement, everything seems OK, but we need to do
a better job on describing why we add code, the context we have now from
all these discussions will be mostly lost, say, 5 years from now when we
try to figure out why something was done in some way,

Thanks,

- Arnaldo
 
> Thanks.
> 
> On 12/07/2011 05:55 PM, Andrew Vagin wrote:
> >Signed-off-by: Andrew Vagin<avagin at openvz.org>
> >---
> >  tools/perf/builtin-record.c |    1 +
> >  tools/perf/perf.h           |    1 +
> >  tools/perf/util/evsel.c     |    3 +++
> >  3 files changed, 5 insertions(+), 0 deletions(-)
> >
> >diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> >index 766fa0a..f8fd14f 100644
> >--- a/tools/perf/builtin-record.c
> >+++ b/tools/perf/builtin-record.c
> >@@ -700,6 +700,7 @@ const struct option record_options[] = {
> >  	OPT_BOOLEAN('d', "data",&record.opts.sample_address,
> >  		    "Sample addresses"),
> >  	OPT_BOOLEAN('T', "timestamp",&record.opts.sample_time, "Sample timestamps"),
> >+	OPT_BOOLEAN('P', "period",&record.opts.period, "Sample period"),
> >  	OPT_BOOLEAN('n', "no-samples",&record.opts.no_samples,
> >  		    "don't sample"),
> >  	OPT_BOOLEAN('N', "no-buildid-cache",&record.no_buildid_cache,
> >diff --git a/tools/perf/perf.h b/tools/perf/perf.h
> >index ea804f5..64f8bee 100644
> >--- a/tools/perf/perf.h
> >+++ b/tools/perf/perf.h
> >@@ -200,6 +200,7 @@ struct perf_record_opts {
> >  	bool	     sample_time;
> >  	bool	     sample_id_all_avail;
> >  	bool	     system_wide;
> >+	bool	     period;
> >  	unsigned int freq;
> >  	unsigned int mmap_pages;
> >  	unsigned int user_freq;
> >diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
> >index e2d1b22..8550018 100644
> >--- a/tools/perf/util/evsel.c
> >+++ b/tools/perf/util/evsel.c
> >@@ -108,6 +108,9 @@ void perf_evsel__config(struct perf_evsel *evsel, struct perf_record_opts *opts)
> >  	if (opts->system_wide)
> >  		attr->sample_type	|= PERF_SAMPLE_CPU;
> >
> >+	if (opts->period)
> >+		attr->sample_type	|= PERF_SAMPLE_PERIOD;
> >+
> >  	if (opts->sample_id_all_avail&&
> >  	(opts->sample_time || opts->system_wide ||
> >  	     !opts->no_inherit || opts->cpu_list))