[PATCH] libperf: Add perf_evsel__id() function

[Charlie Jenkins <charlie@rivosinc.com>]

Introduce perf_evsel__id() to collect the id of an evsel. It is not
currently possible when using libperf to determine the id of an evsel.
This will allow applications to link the id returned by PERF_SAMPLE_ID
to the event being sampled.

Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
---
 tools/lib/perf/Documentation/libperf.txt |  2 ++
 tools/lib/perf/evsel.c                   | 10 ++++++++++
 tools/lib/perf/include/perf/evsel.h      |  1 +
 3 files changed, 13 insertions(+)

diff --git a/tools/lib/perf/Documentation/libperf.txt b/tools/lib/perf/Documentation/libperf.txt
index fcfb9499ef9c..69c1d7efb659 100644
--- a/tools/lib/perf/Documentation/libperf.txt
+++ b/tools/lib/perf/Documentation/libperf.txt
@@ -94,6 +94,8 @@ SYNOPSIS
   void perf_evlist__enable(struct perf_evlist *evlist);
   void perf_evlist__disable(struct perf_evlist *evlist);
 
+  void perf_evsel__id(struct perf_evsel *evsel, u64 *id);
+
   #define perf_evlist__for_each_evsel(evlist, pos)
 
   void perf_evlist__set_maps(struct perf_evlist *evlist,
diff --git a/tools/lib/perf/evsel.c b/tools/lib/perf/evsel.c
index c07160953224..765b17045342 100644
--- a/tools/lib/perf/evsel.c
+++ b/tools/lib/perf/evsel.c
@@ -484,6 +484,16 @@ int perf_evsel__disable(struct perf_evsel *evsel)
 	return err;
 }
 
+int perf_evsel__id(struct perf_evsel *evsel, __u64 *id)
+{
+	int i;
+	int err = 0;
+
+	for (i = 0; i < xyarray__max_x(evsel->fd) && !err; i++)
+		err = perf_evsel__run_ioctl(evsel, PERF_EVENT_IOC_ID, (unsigned long)id, i);
+	return err;
+}
+
 int perf_evsel__apply_filter(struct perf_evsel *evsel, const char *filter)
 {
 	int err = 0, i;
diff --git a/tools/lib/perf/include/perf/evsel.h b/tools/lib/perf/include/perf/evsel.h
index 6f92204075c2..1457e5a46b28 100644
--- a/tools/lib/perf/include/perf/evsel.h
+++ b/tools/lib/perf/include/perf/evsel.h
@@ -41,6 +41,7 @@ LIBPERF_API int perf_evsel__enable_cpu(struct perf_evsel *evsel, int cpu_map_idx
 LIBPERF_API int perf_evsel__enable_thread(struct perf_evsel *evsel, int thread);
 LIBPERF_API int perf_evsel__disable(struct perf_evsel *evsel);
 LIBPERF_API int perf_evsel__disable_cpu(struct perf_evsel *evsel, int cpu_map_idx);
+LIBPERF_API int perf_evsel__id(struct perf_evsel *evsel, __u64 *id);
 LIBPERF_API struct perf_cpu_map *perf_evsel__cpus(struct perf_evsel *evsel);
 LIBPERF_API struct perf_thread_map *perf_evsel__threads(struct perf_evsel *evsel);
 LIBPERF_API struct perf_event_attr *perf_evsel__attr(struct perf_evsel *evsel);

---
base-commit: 47ac09b91befbb6a235ab620c32af719f8208399
change-id: 20240822-perf_evsel_get_id-f7e11f15504b
-- 
- Charlie