[RFC PATCH v2 1/6] perf vendor events arm64: Add topdown L1 metrics for neoverse-n2

[Jing Zhang]

The calculation formula of topdown L1 is from the document:
https://documentation-service.arm.com/static/60250c7395978b529036da86?token=

However, due to the wrong count of stall_slot and stall_slot_frontend
in neoverse-n2, the real stall_slot and real stall_slot_frontend need
to subtract cpu_cycles, so when calculating the topdownL1 metrics,
stall_slot and stall_slot_frontend are corrected.

Since neoverse-n2 does not yet support topdown L2, metricgroups such
as Cache, TLB, Branch, InstructionsMix, and PEutilization will be
added to further analysis of performance bottlenecks in the following
patches.

Signed-off-by: Jing Zhang <renyu.zj at linux.alibaba.com>
---
 .../arch/arm64/arm/neoverse-n2/metrics.json        | 30 ++++++++++++++++++++++
 1 file changed, 30 insertions(+)
 create mode 100644 tools/perf/pmu-events/arch/arm64/arm/neoverse-n2/metrics.json

diff --git a/tools/perf/pmu-events/arch/arm64/arm/neoverse-n2/metrics.json b/tools/perf/pmu-events/arch/arm64/arm/neoverse-n2/metrics.json
new file mode 100644
index 0000000..0048dfe
--- /dev/null
+++ b/tools/perf/pmu-events/arch/arm64/arm/neoverse-n2/metrics.json
@@ -0,0 +1,30 @@
+[
+    {
+        "MetricExpr": "(stall_slot_frontend - cpu_cycles) / (5 * cpu_cycles)",
+        "PublicDescription": "Frontend bound L1 topdown metric",
+        "BriefDescription": "Frontend bound L1 topdown metric",
+        "MetricGroup": "TopDownL1",
+        "MetricName": "frontend_bound"
+    },
+    {
+        "MetricExpr": "(1 - op_retired / op_spec) * (1 - (stall_slot - cpu_cycles) / (5 * cpu_cycles))",
+        "PublicDescription": "Wasted L1 topdown metric",
+        "BriefDescription": "Wasted L1 topdown metric",
+        "MetricGroup": "TopDownL1",
+        "MetricName": "wasted"
+    },
+    {
+        "MetricExpr": "(op_retired / op_spec) * (1 - (stall_slot - cpu_cycles) / (5 * cpu_cycles))",
+        "PublicDescription": "Retiring L1 topdown metric",
+        "BriefDescription": "Retiring L1 topdown metric",
+        "MetricGroup": "TopDownL1",
+        "MetricName": "retiring"
+    },
+    {
+        "MetricExpr": "stall_slot_backend / (5 * cpu_cycles)",
+        "PublicDescription": "Backend Bound L1 topdown metric",
+        "BriefDescription": "Backend Bound L1 topdown metric",
+        "MetricGroup": "TopDownL1",
+        "MetricName": "backend_bound"
+    }
+]
\ No newline at end of file
-- 
1.8.3.1