Re: [PATCH v2] perf inject: Inject build ids for entire call chain

Arnaldo Carvalho de Melo
2024-08-13T14:28:36Z

On Mon, Aug 12, 2024 at 03:41:19PM -0700, Ian Rogers wrote:
> The DSO build id is injected when the dso is first encountered but the
> checking for first encountered only looks at the sample->ip not the
> entire callchain. Use the callchain logic to ensure all build ids are
> inserted.

Split into two patches, one with the paragraph below and the other, a
followup to that, with the fix and the paragraph above.

Applied to perf-tools-next,

Thanks,

- Arnaldo

> Add a for_each callback style API to callchain with
> sample__for_each_callchain_node. Possibly in the future such an API
> can avoid the overhead of constructing the call chain list.
>
> Fixes: 454c407ec17a ("perf: add perf-inject builtin")
> Signed-off-by: Ian Rogers <irogers@google.com>
> Acked-by: Namhyung Kim <namhyung@kernel.org>
> ---
> v2. Rebase and add Namhyung's acked-by.
> ---
> tools/perf/builtin-inject.c | 31 +++++++++++++++++++++++++++++++
> tools/perf/util/callchain.c | 35 +++++++++++++++++++++++++++++++++++
> tools/perf/util/callchain.h | 6 ++++++
> 3 files changed, 72 insertions(+)
>
> diff --git a/tools/perf/builtin-inject.c b/tools/perf/builtin-inject.c
> index ef9cba173dd2..a35bde3f3c09 100644
> --- a/tools/perf/builtin-inject.c
> +++ b/tools/perf/builtin-inject.c
> @@ -743,6 +743,29 @@ static int dso__inject_build_id(struct dso *dso, const struct perf_tool *tool,
> return 0;
> }
>
> +struct mark_dso_hit_args {
> + const struct perf_tool *tool;
> + struct machine *machine;
> + u8 cpumode;
> +};
> +
> +static int mark_dso_hit_callback(struct callchain_cursor_node *node, void *data)
> +{
> + struct mark_dso_hit_args *args = data;
> + struct map *map = node->ms.map;
> +
> + if (map) {
> + struct dso *dso = map__dso(map);
> +
> + if (dso && !dso__hit(dso)) {
> + dso__set_hit(dso);
> + dso__inject_build_id(dso, args->tool, args->machine,
> + args->cpumode, map__flags(map));
> + }
> + }
> + return 0;
> +}
> +
> int perf_event__inject_buildid(const struct perf_tool *tool, union perf_event *event,
> struct perf_sample *sample,
> struct evsel *evsel __maybe_unused,
> @@ -750,6 +773,11 @@ int perf_event__inject_buildid(const struct perf_tool *tool, union perf_event *e
> {
> struct addr_location al;
> struct thread *thread;
> + struct mark_dso_hit_args args = {
> + .tool = tool,
> + .machine = machine,
> + .cpumode = sample->cpumode,
> + };
>
> addr_location__init(&al);
> thread = machine__findnew_thread(machine, sample->pid, sample->tid);
> @@ -769,6 +797,9 @@ int perf_event__inject_buildid(const struct perf_tool *tool, union perf_event *e
> }
> }
>
> + sample__for_each_callchain_node(thread, evsel, sample, PERF_MAX_STACK_DEPTH,
> + mark_dso_hit_callback, &args);
> +
> thread__put(thread);
> repipe:
> perf_event__repipe(tool, event, sample, machine);
> diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
> index 6d075648d2cc..0d608e875fe9 100644
> --- a/tools/perf/util/callchain.c
> +++ b/tools/perf/util/callchain.c
> @@ -1797,3 +1797,38 @@ s64 callchain_avg_cycles(struct callchain_node *cnode)
>
> return cycles;
> }
> +
> +int sample__for_each_callchain_node(struct thread *thread, struct evsel *evsel,
> + struct perf_sample *sample, int max_stack,
> + callchain_iter_fn cb, void *data)
> +{
> + struct callchain_cursor *cursor = get_tls_callchain_cursor();
> + int ret;
> +
> + if (!cursor)
> + return -ENOMEM;
> +
> + /* Fill in the callchain. */
> + ret = thread__resolve_callchain(thread, cursor, evsel, sample,
> + /*parent=*/NULL, /*root_al=*/NULL,
> + max_stack);
> + if (ret)
> + return ret;
> +
> + /* Switch from writing the callchain to reading it. */
> + callchain_cursor_commit(cursor);
> +
> + while (1) {
> + struct callchain_cursor_node *node = callchain_cursor_current(cursor);
> +
> + if (!node)
> + break;
> +
> + ret = cb(node, data);
> + if (ret)
> + return ret;
> +
> + callchain_cursor_advance(cursor);
> + }
> + return 0;
> +}
> diff --git a/tools/perf/util/callchain.h b/tools/perf/util/callchain.h
> index d5c66345ae31..76891f8e2373 100644
> --- a/tools/perf/util/callchain.h
> +++ b/tools/perf/util/callchain.h
> @@ -311,4 +311,10 @@ u64 callchain_total_hits(struct hists *hists);
>
> s64 callchain_avg_cycles(struct callchain_node *cnode);
>
> +typedef int (*callchain_iter_fn)(struct callchain_cursor_node *node, void *data);
> +
> +int sample__for_each_callchain_node(struct thread *thread, struct evsel *evsel,
> + struct perf_sample *sample, int max_stack,
> + callchain_iter_fn cb, void *data);
> +
> #endif /* __PERF_CALLCHAIN_H */
> --
> 2.46.0.76.ge559c4bf1a-goog
>