Change the Hyper-threading Status

The hyper-threading status is controlled by the BIOS settings of the host.

Warning

Some applications may benefit from hyperthreading. For applications that require deterministic performance, it is recommended to run with hyperthreading disabled. If hyperthreading is enabled, the application (either running on bare metal or in a container) must check the CPU topology for the CPUs and affine tasks appropriately to HT siblings. For example, “/proc/cpuinfo” and “/sys/devices/system/cpu/cpuX/topology/thread_siblings*” can be used to identify HT siblings of the same core.

Procedure

1. Lock the host to prepare it for configuration changes.

   In the Hosts list, click More for the host, and then select Lock Host.

   The host is locked and reported as Locked, Disabled, and Online.

2. Edit the host BIOS settings to enable or disable hyper-threading.

   For more about editing the BIOS, refer to the documentation provided by the maker of the host computer.

   Note

   Changes to the host’s BIOS must be made while it is locked and it must not be subsequently unlocked until it comes back online (locked-disabled-online) and the updated Hyperthreading settings are available in the inventory.

   1. Boot the host in BIOS mode.

   2. Update the host BIOS settings to enable or disable hyper-threading.

   3. To apply the changes, allow the host to boot to a locked state with the updated hyper-threading settings.

3. Unlock the host to make it available for use.

   In the Hosts list, on the row associated with the node, open the drop-down menu and select Unlock Host.

   The host is rebooted, and its Availability State is reported as In-Test. After a few minutes, it is reported as Unlocked, Enabled, and Available.

4. Confirm the hyper-threading status in StarlingX.

   The hyper-threading status is reported on the Processor tab for the host. For more information, see Processor Tab.