CPU Placement for Application Instances

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Introduction

CPU placement controls how the vCPUs of an application map to the physical CPUs of the node. It replaces the former on/off CPU Pinning toggle with a topology-aware policy. You choose a CPU pool, how many SMT threads each reserved core runs, and whether the CPUs must fit on one NUMA node. Use CPU placement for latency-sensitive workloads such as real-time data processing, industrial control systems, and AI inference pipelines, where consistent CPU performance matters more than sharing cores with other applications. You set CPU placement in two places:

• On the edge app definition, as the Default for new instances.
• On each application instance, where you can keep the app definition settings or override them. The instance policy always takes precedence over the app definition.

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Prerequisites

• You have the SysManager or SysAdmin role in your enterprise. See Manage Roles.
• The app type is Virtual Machine or Container. Docker Compose apps do not support CPU placement. Module apps keep the legacy Enable CPU Pinning tile on the Drives step.
• To use a pool other than Housekeeping, the target node must report the CPU placement capability. This requires EVE-OS (Edge Virtualization Engine) with CPU placement support on KVM and a CPU topology that EVE-OS can read.
• To use the Isolated pool, the node must be booted with isolated CPUs (isolcpus).

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Placement settings

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CPU pool

Selecting Dedicated or Isolated turns on CPU pinning. Selecting Housekeeping turns it off.

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Core allocation

When the pool is Dedicated or Isolated, select how vCPUs map to physical cores:

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Advanced placement settings

Expand Advanced placement settings to tune whole-core placement. Select Use throughput preset to apply the recommended settings for dedicated physical cores. For Reduced Isolation (native) containers, the CPU pinning row and Disk and device emulation setting are hidden because there is no enclosing VM.

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Set the default on an edge app

CPU placement is part of the Sizing section of the edge app creation wizard. The step is named Resources & CPU for Virtual Machine apps and Features & Sizing for Container apps.

1. In the sidebar, select My Library.
2. Select the Edge Apps filter tab.
3. Select the Create Edge App floating action button.
4. Select Virtual Machine or Container as the app type.
5. Complete the Identity step and click Next.
6. Under Sizing, set vCPUs.
7. In the CPU placement panel, labeled Default for new instances, select a CPU pool.
8. If you selected Dedicated or Isolated, select a Core allocation and, optionally, expand Advanced placement settings.
9. Complete the remaining steps. The Review step shows a summary of the CPU placement policy. Click Create.

The policy applies to new instances of the app. Existing instances keep their CPU settings.

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Edit the default on an existing edge app

You can change the CPU placement policy after an edge app is created.

1. In the sidebar, select My Library and open the edge app.
2. Click the Configure (gear) icon.
3. In the left navigation, select Hardware > Resources.
4. Change the settings in the CPU placement panel.
5. Click Save Changes.

Edge apps created with the former CPU Pinning toggle show Legacy CPU pinning or Legacy shared CPUs. The existing behavior is preserved until you change these settings. To return a changed policy to the legacy setting, expand Restore CPU settings and select Use legacy CPU pinning.

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Override the policy on an application instance

When you deploy an application instance, the Deployment Target step shows a CPU placement panel after you select the edge app.

1. Select one of the following:
   • Use app definition settings to deploy with the edge app’s default policy.
   • Override for this application to set a different policy for this instance only.
2. If you override, change the CPU pool, Core allocation, and advanced settings. The vCPU count comes from the app definition and cannot be changed here.
3. Review the per-node check below the panel. Each selected node shows CPU placement supported or the reason the policy cannot run on it, plus its last reported free capacity. Reported capacity is not a reservation.

To discard the override, click Reset to app definition. An override applies only to this instance. The app definition stays unchanged.

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View the policy and placement status

The application instance detail page shows:

• A CPU placement card on the Details tab with the instance policy: CPU pool, CPU pinning, vCPUs, Profile, Assigned CPUs reported by the node, and Memory locality. Expand CPU policy details for core allocation, SMT threads per core, and disk and device emulation.
• A placement status pill in the header when the node reports a placement condition. See CPU placement status.

If the hosting node does not place CPUs, the card shows This node does not place CPUs; the saved CPU placement policy is not enforced on it.

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Considerations

• Core availability: Dedicated and Isolated reserve CPUs exclusively. If the node does not have enough free cores for the vCPU count, the instance waits for CPUs or cannot be placed. Check the per-node capacity in the deployment wizard before you deploy.
• Even vCPU counts: Both SMT threads per core requires an even vCPU count. Change the vCPU count or select One thread per core.
• Nodes without SMT: On a node with no SMT siblings, select One thread per core or Dedicated logical CPUs.
• Repacking: When CPUs become fragmented, an instance can show Needs repack. A repack runs on the node and restarts every app on that node that needs repacking, not just this one.

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Next Steps