Re: [PATCH v5 2/6] perf record: Get the first sample time and last sample time

Jiri Olsa
2017-10-23T15:04:42Z

On Sat, Oct 21, 2017 at 07:27:50AM +0800, Jin Yao wrote:
> In perf record, it's walked on all samples yet. So it's very easy to get
> 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.
>
> Change log:
> -----------
> 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@linux.intel.com>
> ---
> tools/perf/builtin-record.c | 20 ++++++++++++--------
> 1 file changed, 12 insertions(+), 8 deletions(-)
>
> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index a6cbf16..bd711e8 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -391,8 +391,19 @@ 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 --buildid-all is given, it marks all DSO regardless of hits,
> + * so no need to process this sample.
> + */
> + if (rec->buildid_all)
> + return 0;
>
> + rec->samples++;
> return build_id__mark_dso_hit(tool, event, sample, evsel, machine);
> }
>
> @@ -415,13 +426,6 @@ static int process_buildids(struct record *rec)
> */
> symbol_conf.ignore_vmlinux_buildid = true;
>
> - /*
> - * If --buildid-all is given, it marks all DSO regardless of hits,
> - * so no need to process samples.
> - */
> - if (rec->buildid_all)
> - rec->tool.sample = NULL;

hum, could you still unset the sample if there's no time given?
and keep the speed in this case..

jirka