Re: [PATCH v6 2/6] perf record: Get the first sample time and last sample time

[Jin, Yao]

On 11/22/2017 12:40 AM, Arnaldo Carvalho de Melo wrote:
> Em Mon, Nov 06, 2017 at 08:21:07PM +0800, Jin Yao escreveu:
> > In perf record, it's walked on all samples yet. So it's very easy to get
>
> "In the default 'perf record' configuration, all samples are processed,
> to create the HEADER_BUILD_ID table. So..."
>
> > the first/last samples and save the time to perf file header via the
> > function write_sample_time().
> >
> > In later, perf report/script will fetch the time from perf file header.
>
>    Later, at post processing time, ...

Thanks Arnaldo! The update on patch description is good.

> > Change log:
> > -----------
> > v6: Currently '--buildid-all' is not enabled at default. So the walking
>
>                  --no-buildid-all, right?

No, it is '--buildid-all'. There is no '--no-buildid-all' available now.

See in __record_options[] (builtin-record.c),

	OPT_BOOLEAN(0, "buildid-all", &record.buildid_all,
	    	"Record build-id of all DSOs regardless of hits"),

So by default, buildid-all is set with false.

Thanks
Jin Yao

> >      on all samples is the default operation. There is no big overhead
> >      to calculate the timestamp boundary in process_sample_event handler
> >      once we already go through all samples. So the timestamp boundary
> >      calculation is enabled by default when '--buildid-all' is not enabled.
> >
> >      While if '--buildid-all' is enabled, we creates a new option
> >      "--timestamp-boundary" for user to decide if it enables the
> >      timestamp boundary calculation.
> >
> > v5: There is an issue that the sample walking can only work when
> >      '--buildid-all' is not enabled. So we need to let the walking
> >      be able to work even if '--buildid-all' is enabled and let the
> >      processing skips the dso hit marking for this case.
> >
> >      At first, I want to provide a new option "--record-time-boundaries".
> >      While after consideration, I think a new option is not very
> >      necessary.
> >
> > v3: Remove the definitions of first_sample_time and last_sample_time
> >      from struct record and directly save them in perf_evlist.
> >
> > Signed-off-by: Jin Yao <yao.jin@xxxxxxxxxxxxxxx>
> > ---
> >   tools/perf/Documentation/perf-record.txt |  3 +++
> >   tools/perf/builtin-record.c              | 18 +++++++++++++++---
> >   2 files changed, 18 insertions(+), 3 deletions(-)
> >
> > diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt
> > index 5a626ef..3eea6de 100644
> > --- a/tools/perf/Documentation/perf-record.txt
> > +++ b/tools/perf/Documentation/perf-record.txt
> > @@ -430,6 +430,9 @@ Configure all used events to run in user space.
> >   --timestamp-filename
> >   Append timestamp to output file name.
> >   
> > +--timestamp-boundary::
> > +Record timestamp boundary (time of first/last samples).
> > +
> >   --switch-output[=mode]::
> >   Generate multiple perf.data files, timestamp prefixed, switching to a new one
> >   based on 'mode' value:
> > diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> > index f4d9fc5..082a0cb 100644
> > --- a/tools/perf/builtin-record.c
> > +++ b/tools/perf/builtin-record.c
> > @@ -78,6 +78,7 @@ struct record {
> >   	bool			no_buildid_cache_set;
> >   	bool			buildid_all;
> >   	bool			timestamp_filename;
> > +	bool			timestamp_boundary;
> >   	struct switch_output	switch_output;
> >   	unsigned long long	samples;
> >   };
> > @@ -391,8 +392,15 @@ static int process_sample_event(struct perf_tool *tool,
> >   {
> >   	struct record *rec = container_of(tool, struct record, tool);
> >   
> > -	rec->samples++;
> > +	if (rec->evlist->first_sample_time == 0)
> > +		rec->evlist->first_sample_time = sample->time;
> > +
> > +	rec->evlist->last_sample_time = sample->time;
> >   
> > +	if (rec->buildid_all)
> > +		return 0;
> > +
> > +	rec->samples++;
> >   	return build_id__mark_dso_hit(tool, event, sample, evsel, machine);
> >   }
> >   
> > @@ -417,9 +425,11 @@ static int process_buildids(struct record *rec)
> >   
> >   	/*
> >   	 * If --buildid-all is given, it marks all DSO regardless of hits,
> > -	 * so no need to process samples.
> > +	 * so no need to process samples. But if timestamp_boundary is enabled,
> > +	 * it still needs to walk on all samples to get the timestamps of
> > +	 * first/last samples.
> >   	 */
> > -	if (rec->buildid_all)
> > +	if (rec->buildid_all && !rec->timestamp_boundary)
> >   		rec->tool.sample = NULL;
> >   
> >   	return perf_session__process_events(session);
> > @@ -1579,6 +1589,8 @@ static struct option __record_options[] = {
> >   		    "Record build-id of all DSOs regardless of hits"),
> >   	OPT_BOOLEAN(0, "timestamp-filename", &record.timestamp_filename,
> >   		    "append timestamp to output filename"),
> > +	OPT_BOOLEAN(0, "timestamp-boundary", &record.timestamp_boundary,
> > +		    "Record timestamp boundary (time of first/last samples)"),
> >   	OPT_STRING_OPTARG_SET(0, "switch-output", &record.switch_output.str,
> >   			  &record.switch_output.set, "signal,size,time",
> >   			  "Switch output when receive SIGUSR2 or cross size,time threshold",
> > --
> > 2.7.4