Specify CPU options for your instance - Amazon Elastic Compute Cloud
Disable multithreadingSpecify a custom number of vCPUs at launchSpecify a custom number of vCPUs in a launch template
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Specify CPU options for your instance

You can specify CPU options during instance launch.

The following examples describe how to specify the CPU options when using the launch instance wizard in the EC2 console and the run-instances Amazon CLI command, and the create launch template page in the EC2 console and the create-launch-template Amazon CLI command. For EC2 Fleet or Spot Fleet, you must specify the CPU options in a launch template.

The following examples are for an r5.4xlarge instance type, which has the following default values:

  • Default CPU cores: 8

  • Default threads per core: 2

  • Default vCPUs: 16 (8 * 2)

  • Valid number of CPU cores: 2, 4, 6, 8

  • Valid number of threads per core: 1, 2

Disable multithreading

To disable multithreading, specify 1 thread per core.

New console
To disable multithreading during instance launch

  1. Follow the Quickly launch an instance procedure and configure your instance as needed.

  2. Expand Advanced details, and select the Specify CPU options check box.

  3. For Core count, choose the number of required CPU cores. In this example, to specify the default CPU core count for an r5.4xlarge instance, choose 8.

  4. To disable multithreading, for Threads per core, choose 1.

  5. In the Summary panel, review your instance configuration, and then choose Launch instance. For more information, see Launch an instance using the new launch instance wizard.

Old console
To disable multithreading during instance launch

  1. Follow the Launch an instance using the old launch instance wizard procedure.

  2. On the Configure Instance Details page, for CPU options, choose Specify CPU options.

  3. For Core count, choose the number of required CPU cores. In this example, to specify the default CPU core count for an r5.4xlarge instance, choose 8.

  4. To disable multithreading, for Threads per core, choose 1.

  5. Continue as prompted by the wizard. When you've finished reviewing your options on the Review Instance Launch page, choose Launch. For more information, see Launch an instance using the old launch instance wizard.

Amazon CLI
To disable multithreading during instance launch

Use the run-instances Amazon CLI command and specify a value of 1 for ThreadsPerCore for the --cpu-options parameter. For CoreCount, specify the number of CPU cores. In this example, to specify the default CPU core count for an r5.4xlarge instance, specify a value of 8.

aws ec2 run-instances \
    --image-id ami-1a2b3c4d \
    --instance-type r5.4xlarge \
    --cpu-options "CoreCount=8,ThreadsPerCore=1" \
    --key-name MyKeyPair

Specify a custom number of vCPUs at launch

You can customize the number of CPU cores and threads per core for the instance.

The following example launches an r5.4xlarge instance with 4 vCPUs.

New console
To specify a custom number of vCPUs during instance launch

  1. Follow the Quickly launch an instance procedure and configure your instance as needed.

  2. Expand Advanced details, and select the Specify CPU options check box.

  3. To get 4 vCPUs, specify 2 CPU cores and 2 threads per core, as follows:

    • For Core count, choose 2.

    • For Threads per core, choose 2.

  4. In the Summary panel, review your instance configuration, and then choose Launch instance. For more information, see Launch an instance using the new launch instance wizard.

Old console
To specify a custom number of vCPUs during instance launch

  1. Follow the Launch an instance using the old launch instance wizard procedure.

  2. On the Configure Instance Details page, for CPU options, choose Specify CPU options.

  3. To get 4 vCPUs, specify 2 CPU cores and 2 threads per core, as follows:

    • For Core count, choose 2.

    • For Threads per core, choose 2.

  4. Continue as prompted by the wizard. When you've finished reviewing your options on the Review Instance Launch page, choose Launch. For more information, see Launch an instance using the old launch instance wizard.

Amazon CLI
To specify a custom number of vCPUs during instance launch

Use the run-instances Amazon CLI command and specify the number of CPU cores and number of threads in the --cpu-options parameter. You can specify 2 CPU cores and 2 threads per core to get 4 vCPUs.

aws ec2 run-instances \
    --image-id ami-1a2b3c4d \
    --instance-type r5.4xlarge \
    --cpu-options "CoreCount=2,ThreadsPerCore=2" \
    --key-name MyKeyPair

Alternatively, specify 4 CPU cores and 1 thread per core (disable multithreading) to get 4 vCPUs:

aws ec2 run-instances \
    --image-id ami-1a2b3c4d \
    --instance-type r5.4xlarge \
    --cpu-options "CoreCount=4,ThreadsPerCore=1" \
    --key-name MyKeyPair

Specify a custom number of vCPUs in a launch template

You can customize the number of CPU cores and threads per core for the instance in a launch template.

The following example creates a launch template that specifies the configuration for an r5.4xlarge instance with 4 vCPUs.

Console
To specify a custom number of vCPUs in a launch template

  1. Follow the Create a launch template from parameters procedure and configure your launch template as needed.

  2. Expand Advanced details, and select the Specify CPU options check box.

  3. To get 4 vCPUs, specify 2 CPU cores and 2 threads per core, as follows:

    • For Core count, choose 2.

    • For Threads per core, choose 2.

  4. In the Summary panel, review your instance configuration, and then choose Create launch template. For more information, see Launch an instance from a launch template.

Amazon CLI
To specify a custom number of vCPUs in a launch template

Use the create-launch-template Amazon CLI command and specify the number of CPU cores and number of threads in the CpuOptions parameter. You can specify 2 CPU cores and 2 threads per core to get 4 vCPUs.

aws ec2 create-launch-template \
    --launch-template-name TemplateForCPUOptions \
    --version-description CPUOptionsVersion1 \
    --launch-template-data file://template-data.json

The following is an example JSON file that contains the launch template data, which includes the CPU options, for the instance configuration for this example.

{
    "NetworkInterfaces": [{
        "AssociatePublicIpAddress": true,
        "DeviceIndex": 0,
        "Ipv6AddressCount": 1,
        "SubnetId": "subnet-7b16de0c"
    }],
    "ImageId": "ami-8c1be5f6",
    "InstanceType": "r5.4xlarge",
    "TagSpecifications": [{
        "ResourceType": "instance",
        "Tags": [{
            "Key":"Name",
            "Value":"webserver"
        }]
    }],
    "CpuOptions": {
        "CoreCount":2,
        "ThreadsPerCore":2
    }
}

Alternatively, specify 4 CPU cores and 1 thread per core (disable multithreading) to get 4 vCPUs:

{
    "NetworkInterfaces": [{
        "AssociatePublicIpAddress": true,
        "DeviceIndex": 0,
        "Ipv6AddressCount": 1,
        "SubnetId": "subnet-7b16de0c"
    }],
    "ImageId": "ami-8c1be5f6",
    "InstanceType": "r5.4xlarge",
    "TagSpecifications": [{
        "ResourceType": "instance",
        "Tags": [{
            "Key":"Name",
            "Value":"webserver"
        }]
    }],
    "CpuOptions": {
        "CoreCount":4,
        "ThreadsPerCore":1
    }
}