[PATCH v2 4/4 fix] arm64: add a new document for the fine-tuning tips

[Huang Shijie <shijie@os.amperecomputing.com>]

Put some fine-tuning tips in this file:
	1.) rodata=noalias
	2.) slab_strict_numa
	3.) CONFIG_SCHED_CLUSTER

We can add more tips in future.

Signed-off-by: Huang Shijie <shijie@os.amperecomputing.com>
---
Add the comment from Christoph.
---
 Documentation/arch/arm64/fine-tuning-tips.rst | 25 +++++++++++++++++++
 Documentation/arch/arm64/index.rst            |  1 +
 2 files changed, 26 insertions(+)
 create mode 100644 Documentation/arch/arm64/fine-tuning-tips.rst

diff --git a/Documentation/arch/arm64/fine-tuning-tips.rst b/Documentation/arch/arm64/fine-tuning-tips.rst
new file mode 100644
index 000000000000..df67a5ac87b9
--- /dev/null
+++ b/Documentation/arch/arm64/fine-tuning-tips.rst
@@ -0,0 +1,25 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+================
+fine-tuning tips
+================
+
+This file contains some fine-tuning tips for arm64 machines.
+These tips do not gurantee that you can get better performance,
+but you can try them with your workload.
+
+rodata=noalias
+----------------
+It can provide us more block mappings and contiguous hits
+to map the linear region which minimizes the TLB footprint.
+
+slab_strict_numa
+----------------
+In NUMA, it will provide the local memory allocation by SLUB.
+Slab objects will be placed individually according to memory policies.
+Increases object locality which is useful for NUMA systems using SLC caches.
+
+CONFIG_SCHED_CLUSTER
+----------------
+Some arm64 machines have cpu core clusters, enable it may
+helps you get better performance.
diff --git a/Documentation/arch/arm64/index.rst b/Documentation/arch/arm64/index.rst
index 6a012c98bdcd..36d1ef09bd71 100644
--- a/Documentation/arch/arm64/index.rst
+++ b/Documentation/arch/arm64/index.rst
@@ -16,6 +16,7 @@ ARM64 Architecture
     cpu-feature-registers
     cpu-hotplug
     elf_hwcaps
+    fine-tuning-tips
     gcs
     hugetlbpage
     kdump
-- 
2.40.1