Configuring the BIOS

Purpose

Configure advanced BIOS settings to improve server performance.

• The system storage management unit ( SMMU ) on the server translates device addresses and isolates devices, playing an important part in virtualization. However, the SMMU may compromise performance in a physical machine test scenario, especially in a small-packet network scenario. Therefore, you are advised to disable the SMMU for higher server performance. In VM scenarios, you need to enable the SMMU to use the PCI passthrough function.
• In this test scenario, prefetch causes cache pollution and increases cache misses. Therefore, you are advised to disable the prefetch function.

Procedure

1. Tune the SMMU.

   In scenarios involving physical machines or load balancing, disable the SMMU using method 1. In VM scenarios, enable the SMMU using method 2.

   Method 1:

   1. Restart the server and enter the BIOS.

      For details, see "Accessing the BIOS" in TaiShan Server BIOS Parameter Reference (Kunpeng 920 Processor).

   2. Choose Advanced > MISC Config > Support Smmu.

      

   3. Set Support Smmu to Disabled. Press F10 to save the settings and exit. The settings are permanently valid.

      

   Method 2:

   1. Set Support Smmu to Enabled. For details, see the procedure in method 1.

      

   2. Restart the OS.
   3. Open the grub2-efi.cfg file.

      1	vim /etc/grub2-efi.cfg

   4. Press i to enter the insert mode, search for the 4.14 field, and add iommu.passthrough=1 to the kernel code.

      

   5. Press Esc, type :wq!, and press Enter to save the file and exit.
   6. Restart the server.
2. Disable prefetch.
   1. Access the BIOS Setup Utility.
   2. Choose Advanced > MISC Config > CPU Prefetching Configuration.

      

   3. Set CPU Prefetching Configuration to Disabled, and press F10 to save the configuration and exit (the configuration is permanently valid).

      

3. Set the memory refresh rate to 64 ms.
   1. In the BIOS, choose Advanced > Memory Config and press Enter.

      

   2. Set Custom Refresh Rate to 64ms.

      

4. Set the power policy to performance first.
   1. In the BIOS, choose Advanced > Performance Config and press Enter.

      

   2. Set Power Policy to Performance and press F10 to save the settings and exit.