[PATCH V2 3/6] perf: Support branch events

[kan . liang]

From: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>

With the cycle time information between branches, stalls can be easily
observed. But it's difficult to explain what causes the long delay.

Add a new branch sample type to indicate whether include occurrences of
events in branch info. The information will be stored in the branch
stack extension space.

Reviewed-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Signed-off-by: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
---

Changes since V1:
- Rename to PERF_SAMPLE_BRANCH_EVT_CNTRS
- Drop the event ID sample type

 include/linux/perf_event.h      | 4 ++++
 include/uapi/linux/perf_event.h | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index e2e04dc39199..823c6779a96d 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -1137,6 +1137,10 @@ static inline bool branch_sample_priv(const struct perf_event *event)
 	return event->attr.branch_sample_type & PERF_SAMPLE_BRANCH_PRIV_SAVE;
 }
 
+static inline bool branch_sample_evt_cntrs(const struct perf_event *event)
+{
+	return event->attr.branch_sample_type & PERF_SAMPLE_BRANCH_EVT_CNTRS;
+}
 
 struct perf_sample_data {
 	/*
diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
index 1b3b90965b6b..3911cf000e8a 100644
--- a/include/uapi/linux/perf_event.h
+++ b/include/uapi/linux/perf_event.h
@@ -204,6 +204,8 @@ enum perf_branch_sample_type_shift {
 
 	PERF_SAMPLE_BRANCH_PRIV_SAVE_SHIFT	= 18, /* save privilege mode */
 
+	PERF_SAMPLE_BRANCH_EVT_CNTRS_SHIFT	= 19, /* save occurrences of events on a branch */
+
 	PERF_SAMPLE_BRANCH_MAX_SHIFT		/* non-ABI */
 };
 
@@ -235,6 +237,8 @@ enum perf_branch_sample_type {
 
 	PERF_SAMPLE_BRANCH_PRIV_SAVE	= 1U << PERF_SAMPLE_BRANCH_PRIV_SAVE_SHIFT,
 
+	PERF_SAMPLE_BRANCH_EVT_CNTRS	= 1U << PERF_SAMPLE_BRANCH_EVT_CNTRS_SHIFT,
+
 	PERF_SAMPLE_BRANCH_MAX		= 1U << PERF_SAMPLE_BRANCH_MAX_SHIFT,
 };
 
-- 
2.35.1