This article describes how to check extra C-States are enabled in the host without rebooting into the BIOS.

Instructions

Complete the following procedure:

1. Open a console to the host, it could be using a SSH client, the console tab in XenCenter, or the local console.

2. Run the following command:
   xenpm get-cpuidle-states | grep total | uniq

3. If extra C-States are enabled, the command in step 2 generates an output similar to this:
   total C-states: 4

4. If no extra C-States have been enabled, the output is similar to the following:
   total C-states: 2

Note: If the value of total C-States is bigger than 2, the extra C-States have been enabled and as per CTX127395 – Hosts Become Unresponsive with XenServer 5.6 and above on Nehalem and Westmere CPUs.

C-States must be disabled from the BIOS.

CTX127395 – Hosts Become Unresponsive with XenServer 5.6 and above on Nehalem and Westmere CPUs