OS Configuration

This section describes how to optimize the Linux kernel page size based on the openEuler OS.

Principle

As the most fundamental memory allocation structure in the operating system, the page table in the Arm64 architecture supports different page sizes, including 4 KB, 16 KB, and 64 KB. Currently, the page table size can only be statically configured and does not support dynamic modification. Page table size is closely correlated with server performance. In inference scenarios, adjusting the page table size based on varying workload requirements can yield substantial performance gains.

Tuning Configuration

This section uses openEuler 22.03 LTS SP4 installed on the Atlas 900 Pod A2 as an example to describe how to perform tuning.

openEuler 22.03 LTS SP4 uses a 4 KB page table by default. Change the page table size to 64 KB and test the inference performance of common NLP models before and after the size change.

Run the following command to query the size of the Linux kernel page table:

getconf PAGESIZE

You can change the size of the Linux kernel page table in either of the following ways:

Method 1: Download the 64 KB kernel installation package provided by the official website and run the following command to install it:

rpm -ivh --nodeps --force *.rpm

Method 2: Compile and install the source code.

Install the required dependencies.

yum install -y ncurses-devel bc openssl-devel rpm-build bison flex rsync dwarves elfutils-libelf-devel

Obtain the kernel source code.
```
yum -y install kernel-source 
```
The downloaded kernel source code is saved in the /usr/src directory.
Compile the kernel.
1. Open the configuration file.
```
cd /usr/src/linux-5.10.0-254.0.0.158.oe2203sp4.aarch64
vim .config
```
  In the .config file, change the value of CONFIG_LOCALVERSION to 64k. This parameter is used to display the new kernel version number. This is to distinguish the default kernel from the kernel of 64 KB.
2. Make the configuration file take effect and modify the kernel parameter.
```
make menuconfig
```
3. On the GUI, choose Kernel Features > Page Size, set Page Size to 64KB, save the settings, and exit.
4. Run the compilation command.
```
make rpm-pkg -j 
```
  After the compilation is complete, the generated kernel RPM installation package is saved in the /root/rpmbuild/RPMS/aarch64 directory.

Install the kernel package.

cd /root/rpmbuild/RPMS/aarch64
rpm -ivh --nodeps --force *.rpm

Reboot the server.
```
reboot 
```
After the restart, check the kernel and page size.
```
uname -a
```
The result shows that the page size has been changed to 64 KB.

Performance Test Result

The test models are from MindSpeed LLM. For details, see the official website.

**Table 1** Experimental data
os	Model	Experiment No.	Inference Duration (s) Page Size: 4 KB	Inference Duration (s) Page Size: 64 KB	Performance Gains (%)
openEuler 22.03 SP4	llama2_7b	Experiment 1	15.49	13.83	10.7166
		Experiment 2	16.02	14.18	11.4856
		Experiment 3	15.73	13.99	11.0617
		Average	15.75	14	11.0923
	deepseek_r1	Experiment 1	10.91	9.79	10.2658
		Experiment 2	11.03	9.79	11.2421
		Experiment 3	10.99	9.36	14.8317
		Average	10.98	9.65	12.1166

Parent topic: High-Performance Configuration