how can i enable hyperthreading on an azure vm e series

Konstantinos Takavakidis 1

I have an IaaS vm E series and I want to enable hyperthreading because I have installed oracle on this VM. How can I enable this on the vm?

kobulloc-MSFT 23,181 Reputation points Microsoft Employee

2022-02-06T17:53:30.857+00:00

Hello, @Konstantinos Takavakidis !

The Oracle license has special rules for multi-threading processors so it's important to know what counts as hyper-threading:

https://www.oracle.com/us/corporate/pricing/cloud-licensing-070579.pdf

Microsoft Azure – count two vCPUs as equivalent to one Oracle Processor license if multithreading of processor cores is enabled, and one vCPU as equivalent to one Oracle Processor license if multi-threading of processor cores is not enabled.

It appears that hyperthreading is enabled by default, both in the description of the VM announcement and in some of the documentation that refers to steps for disabling multi-threading in special scenarios but I would need to confirm that as I don't see it explicitly stated anywhere.
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Ningappa Kempannavar 0 Reputation points

2023-03-24T16:09:52.8033333+00:00

Hyperthreading and multi threading are same?
Ningappa Kempannavar 0 Reputation points

2023-03-24T16:10:04.7266667+00:00

How to check azure VM's CPU is enabled with multithread or not ?
kobulloc-MSFT 23,181 Reputation points Microsoft Employee

2023-03-24T16:14:24.9033333+00:00

Hello,@Ningappa Kempannavar !

Hyperthreading is divides a single physical processor into two logical/virtual processors, while multithreading allows multiple threads to run simultaneously within a single process. Read more here.

You can see which VM sizes have multithreading here:
https://learn.microsoft.com/en-us/azure/virtual-machines/acu

For additional questions, please start a thread in Microsoft Q&A so we can answer them.

1 answer

kobulloc-MSFT 23,181 Reputation points Microsoft Employee

2022-02-07T17:29:11.507+00:00
Hello, @Konstantinos Takavakidis !

The Oracle license has special rules for multi-threading processors so it's important to know if hyper-threading is enabled on your virtual machine. I created a hyper-thread capable VM (an Ev3) and as you can see below, hyper-threading was enabled by default (you are asked to contact support to disable hyper-threading ).

Windows
You can check if hyper-threading is enabled using WMIC:

From a command prompt, type wmic

In the interactive interface, type CPU Get NumberOfCores,NumberOfLogicalProcessors /Format:List

If the number of logical processors (cores) is greater than the number of physical processors (cores), then hyper-threading is enabled.

Linux
You can check if hyper-threading is enabled using lscpu:

Run the lscpu command in the Linux VM

If Thread(s) per core = 2, then hyper-threading has been enabled (Thread(s) per core = 1 would indicate hyper-threading has been disabled).

More reading:
https://learn.microsoft.com/en-us/azure/virtual-machines/mitigate-se#enabling-additional-security
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