[PATCH 1/8] perf sample: Add file_offset field to struct perf_sample

[Arnaldo Carvalho de Melo <acme@kernel.org>]

From: Arnaldo Carvalho de Melo <acme@redhat.com>

Add a file_offset field to struct perf_sample so that event processing
callbacks can report the byte offset of the problematic event in
perf.data, letting users cross-reference with 'perf report -D' output.

Set sample.file_offset in perf_session__deliver_event(), which is the
common entry point for both file mode (mmap'd offset) and pipe mode
(running byte counter from __perf_session__process_pipe_events).

The assignment is placed after evsel__parse_sample(), which zeroes
the struct via memset.

Preserve file_offset through the deferred callchain delivery path by
storing it in struct deferred_event and restoring it after
evlist__parse_sample() in both evlist__deliver_deferred_callchain()
and session__flush_deferred_samples().

Subsequent patches will use this field in skip/stop warning messages.

Assisted-by: Claude Opus 4.6 <noreply@anthropic.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/sample.h  | 2 ++
 tools/perf/util/session.c | 5 +++++
 2 files changed, 7 insertions(+)

diff --git a/tools/perf/util/sample.h b/tools/perf/util/sample.h
index e556c9b656ea9cd6..c4eae8b2fd06035a 100644
--- a/tools/perf/util/sample.h
+++ b/tools/perf/util/sample.h
@@ -158,6 +158,8 @@ struct perf_sample {
 	u64 code_page_size;
 	/** @cgroup: The sample event PERF_SAMPLE_CGROUP value. */
 	u64 cgroup;
+	/** @file_offset: Byte offset of this event in the perf.data file. */
+	u64 file_offset;
 	/** @flags: Extra flag data from auxiliary events like intel-pt. */
 	u32 flags;
 	/** @machine_pid: The guest machine pid derived from the sample id. */
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index e2e821b77766dbfc..7996787d742e32c6 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -1824,6 +1824,7 @@ static int evlist__deliver_sample(struct evlist *evlist, const struct perf_tool
 struct deferred_event {
 	struct list_head list;
 	union perf_event *event;
+	u64 file_offset;
 };
 
 /*
@@ -1858,6 +1859,7 @@ static int evlist__deliver_deferred_callchain(struct evlist *evlist,
 			perf_sample__exit(&orig_sample);
 			break;
 		}
+		orig_sample.file_offset = de->file_offset;
 
 		if (sample->tid != orig_sample.tid) {
 			perf_sample__exit(&orig_sample);
@@ -1906,6 +1908,7 @@ static int session__flush_deferred_samples(struct perf_session *session,
 			perf_sample__exit(&sample);
 			break;
 		}
+		sample.file_offset = de->file_offset;
 
 		sample.evsel = evlist__id2evsel(evlist, sample.id);
 		ret = evlist__deliver_sample(evlist, tool, de->event,
@@ -1984,6 +1987,7 @@ static int machines__deliver_event(struct machines *machines,
 				return -ENOMEM;
 			}
 			memcpy(de->event, event, sz);
+			de->file_offset = sample->file_offset;
 			list_add_tail(&de->list, &evlist->deferred_samples);
 			return 0;
 		}
@@ -2126,6 +2130,7 @@ static int perf_session__deliver_event(struct perf_session *session,
 		pr_err("Can't parse sample, err = %d\n", ret);
 		goto out;
 	}
+	sample.file_offset = file_offset;
 	/*
 	 * evsel__parse_sample() doesn't populate machine_pid/vcpu,
 	 * which are needed by machines__find_for_cpumode() to
-- 
2.54.0