Re: [PATCH 4/6] perf script: add call path id to exported sample in db export

From: Adrian Hunter
Date: Fri May 06 2016 - 07:32:03 EST


On 28/04/16 11:19, Chris Phlipot wrote:
> The exported sample now contains a reference to the call_path_id that
> represents its callchain.
>
> While callchains themselves are nice to have, being able to associate
> them with samples makes them much more useful, and can allow for such
> things as determining how much cumulative time is spent in a particular
> function. This information is normally possible to get from the
> call return processor. However, when doing normal sampling, call/return
> information is not available, thus necessitating the need for associating
> samples directly with call paths.
>
> This commit include changes to db-export layer to make this information
> available for subsequent patches in this change set, but by itself, does
> not make any changes visible to the user.
>
> Signed-off-by: Chris Phlipot <cphlipot0@xxxxxxxxx>

Acked-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>

> ---
> tools/perf/util/db-export.c | 4 +++-
> tools/perf/util/db-export.h | 1 +
> 2 files changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/tools/perf/util/db-export.c b/tools/perf/util/db-export.c
> index cb96591..74f6875 100644
> --- a/tools/perf/util/db-export.c
> +++ b/tools/perf/util/db-export.c
> @@ -412,8 +412,10 @@ int db_export__sample(struct db_export *dbe, union perf_event *event,
> struct call_path *cp = call_path_from_sample(dbe, al->machine,
> thread, sample,
> evsel);
> - if (cp)
> + if (cp) {
> db_export__call_path(dbe, cp);
> + es.call_path_id = cp->db_id;
> + }
> }
>
> if ((evsel->attr.sample_type & PERF_SAMPLE_ADDR) &&
> diff --git a/tools/perf/util/db-export.h b/tools/perf/util/db-export.h
> index f5daf55..67bc6b8 100644
> --- a/tools/perf/util/db-export.h
> +++ b/tools/perf/util/db-export.h
> @@ -44,6 +44,7 @@ struct export_sample {
> u64 addr_dso_db_id;
> u64 addr_sym_db_id;
> u64 addr_offset; /* addr offset from symbol start */
> + u64 call_path_id;
> };
>
> struct db_export {
>