On 2024/12/6 11:56, Anshuman Khandual wrote:
On 11/26/24 14:26, Huang Shijie wrote:
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@xxxxxxxxxxxxxxxxxxxxxx>
---
Documentation/arch/arm64/fine-tuning-tips.rst | 23 +++++++++++++++++++
Documentation/arch/arm64/index.rst | 1 +
2 files changed, 24 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..70ef1cef92fb
--- /dev/null
+++ b/Documentation/arch/arm64/fine-tuning-tips.rst
@@ -0,0 +1,23 @@
+.. 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.
+
+CONFIG_SCHED_CLUSTER
+----------------
+Some arm64 machines have cpu core cluster, 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
Although the idea for such a file makes sense, to help system admins
tune the kernel command line for required behaviour, I am concerned
This file also contains the CONFIG_SCHED_CLUSTER which is not a kernel
command line.
about the overall structure and scope for such a document. Should it
contain tips regarding all the subsystems on the platform, till what
extent these details should be described in there and then there are
so many aspects for a required behaviour etc ?
My original thought is to let this file contains the tips only works in
arm64.
All the tips which _may_ make the arm64 machines get better performance
can be
recorded here.
Then the arm64 kernel engineers(the newbies) can follow this file, and
ramp up
quickly.
Besides maintaining such a document might also be very difficult as
well given how implementations will change over time thus requiring
different tuning etc. Hence kernel source might not be a place for
such a document.
okay. If the kernel source is not the right place, I can remove this
patch in next version.
Thanks
Huang Shijie
