What causes CPU throttling in Kubernetes?

CPU throttling occurs when a container's CFS (Completely Fair Scheduler) quota is exhausted within a 100ms period. Even a container using less than its CPU limit on average can be throttled during short bursts.

How do I diagnose CPU throttling?

Check container_cpu_throttled_seconds_total and container_cpu_cfs_throttled_periods_total in Prometheus. Throttling > 25% of periods indicates the CPU limit is too low relative to peak demand.

CPU Throttling Headroom Calculator

Calculate CPU throttling headroom for containerised workloads (Kubernetes cgroups). Estimates how close a pod is to its CPU limit and probability of throttling at peak load.

Networking

Algorithms

Binary & Number

Systems

Dev Metrics

IP Subnet Calculator

IP Address

CIDR Prefix

Network

192.168.1.0

Broadcast

192.168.1.255

Subnet Mask

255.255.255.0

First Host

192.168.1.1

Last Host

192.168.1.254

Usable Hosts

254

Binary breakdown:

IP: 11000000.10101000.00000001.00000000

Mask: 11111111.11111111.11111111.00000000

Net: 11000000.10101000.00000001.00000000

How to Use

Enter the values for the patient or scenario you are assessing. Calculate CPU throttling headroom for containerised workloads (Kubernetes cgroups). Estimates how close a pod is to its CPU limit and probability of throttling at peak load. Use the cpu throttling headroom result to inform your clinical assessment.

CPU Throttling Headroom Calculator

IP Subnet Calculator

How to Use

Frequently Asked Questions

What causes CPU throttling in Kubernetes?

How do I diagnose CPU throttling?