Configuring the BIOS

Purpose

Configure advanced BIOS settings to improve server performance.

• The system memory 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 data transmission scenario. Therefore, you are advised to disable the SMMU function for higher server performance. In the VM scenario, enable this function to use the PCI passthrough function.
• In this test scenario, prefetching causes Cache pollution and increases Cache misses. Therefore, you are advised to disable the prefetching function.

Procedure

1. Disable the SMMU.
   1. Restart the server and enter the BIOS Setup Utility.

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

   2. Choose Advanced > MISC Config > Support Smmu.
      Figure 1 BIOS Setup Utility
      
   3. Set Support Smmu to Disabled and press F10 to save the configuration and exit (the configuration is permanently valid).
      Figure 2 BIOS screen used for disabling the SMMU
      
2. Disable prefetch.
   1. Access BIOS Setup Utility.
   2. Choose Advanced > MISC Config > CPU Prefetching Configuration.
      Figure 3 BIOS Setup Utility
      
   3. Set CPU Prefetching Configuration to Disabled, and press F10 to save the configuration and exit (the configuration is permanently valid).
      Figure 4 BIOS screen for closing the CPU Prefetching Configuration