CPU Ready

Definition of CPU Ready

CPU Ready is a performance metric that indicates the amount of time a virtual machine (VM) is waiting in a queue for CPU resources before it can be processed. It signifies that a VM is prepared to execute but held back due to other VMs consuming resources or a lack of available CPU cycles. High CPU Ready values indicate potential performance bottlenecks or contention for CPU resources in a virtualized environment.


The phonetic pronunciation of the keyword “CPU Ready” is:C – P – U: /ˌsiː piː ˈjuː/Ready: /ˈrɛdi/In the International Phonetic Alphabet (IPA): /ˌsiː piː ˈjuː ˈrɛdi/

Key Takeaways

  1. CPU Ready is a performance metric that measures the amount of time a virtual machine is waiting in the queue to get access to the CPU for processing.
  2. High CPU Ready values indicate CPU contention and can lead to slow performance for the affected virtual machines, as well as affecting the overall performance of the host.
  3. Monitoring and managing CPU Ready values can help optimize resource allocation and ensure consistent performance across all virtual machines within a host or cluster.

Importance of CPU Ready

CPU Ready is an important term in technology as it refers to the time a virtual machine (VM) has to wait before being allocated a physical processor for execution.

It serves as a crucial metric in virtualized environments to assess the efficiency and performance of the resources being allocated to VMs.

High CPU Ready time indicates that the VM is consistently waiting for CPU resources, which could lead to slower response times, reduced performance, and poor user experience.

Monitoring and managing CPU Ready time is essential to maintain optimal resource allocation, avoid potential bottlenecks, and ensure the smooth functioning of applications and systems running on virtual machines.


CPU Ready is a critical metric used to assess the efficiency and performance of a computer system, particularly in virtualized environments. The primary purpose of CPU Ready is to indicate the percentage of time a virtual machine (VM) is prepared to execute tasks but has to wait for the physical CPU resources to become available.

In simpler terms, it is a measure of how long a VM is waiting in line to access the host computer’s essential processing power. By continuously monitoring this key performance indicator, IT professionals can identify potential bottlenecks and optimize resource allocation, ensuring that their virtualized environments are running smoothly and minimizing latency issues.

To further illustrate the importance of CPU Ready in virtualized infrastructures, consider a peak-demand scenario where multiple applications hosted on different VMs are competing for processing capacity. In such situations, prolonged CPU Ready times could be indicative of a need to redistribute load across the environment or add additional physical CPUs to the host machine.

When the VMs face frequent delays in acquiring CPU resources, application performance may deteriorate, causing a negative impact on end-user experiences. By actively addressing CPU Ready concerns and efficiently utilizing the available resources, administrators can improve overall system performance and better cater to varying workloads, ensuring optimal end-user satisfaction.

Examples of CPU Ready

CPU Ready, also known as CPU Readiness or CPU_READY, is a metric used to measure the amount of time a virtual machine (VM) spends waiting for CPU resources to become available on a host server. It is an indicator of the performance and efficiency of a virtualized environment. Here are three real-world examples related to CPU Ready:

Data Center Performance Monitoring: In a data center with multiple virtualized servers, IT administrators can monitor CPU Ready metrics to identify potential performance bottlenecks. High CPU Ready values may indicate that the physical server’s CPU resources are being over-allocated, causing VMs to wait for processing resources. By analyzing this metric, administrators can ensure fair distribution of CPU resources among all the VMs and improve overall server performance.

Cloud Service Providers: Cloud service providers often run VMs for multiple customers on shared host servers. CPU Ready can help them identify and prevent resource contention and overprovisioning. By constantly monitoring and using this metric, service providers can optimize resource allocation for each customer’s VMs, ensuring that each customer receives the necessary resources and minimizing the impact of the noisy neighbor problem.

Virtual Desktop Infrastructure (VDI): In a VDI environment, many desktop workstations are virtualized on a shared host server. High CPU Ready values can cause slower performance and lag for end-users. Monitoring and managing CPU Ready in a VDI environment ensures all virtual workstations have the necessary processing resources, improving the end-user experience, productivity, and satisfaction.


1. What is CPU Ready?

CPU Ready is a performance metric that represents the time a virtual machine is waiting to be scheduled for execution on the physical CPU by the hypervisor. It’s an important factor to consider during performance monitoring and troubleshooting for virtualized environments.

2. How is CPU Ready measured?

CPU Ready is usually measured in milliseconds (ms) and represents the total time a virtual machine has been waiting in the ready queue. It can be measured by using performance monitoring tools specific to the hypervisor or virtualization platform you are using, such as VMware’s vSphere or Microsoft’s Hyper-V.

3. What causes high CPU Ready values?

High CPU Ready values can be caused by several factors, including CPU over-commitment, resource contention among virtual machines, inefficient resource allocation, or running resource-intensive applications on the virtual machines. Identifying and addressing these issues can help in reducing CPU Ready times and improve overall performance.

4. How can I reduce CPU Ready time?

Reducing CPU Ready time can be achieved by optimizing resource allocation, balancing the distribution of virtual machines across your infrastructure, adjusting CPU reservations, and limiting resource-intensive applications. Regular monitoring and analysis of your virtual environment can help in identifying opportunities for optimization and reducing CPU Ready times.

5. What is an acceptable CPU Ready value?

An acceptable CPU Ready value depends on the specific virtual environment and the applications being run. However, as a general guideline, a CPU Ready value below 5% is considered acceptable for most environments. Values higher than this may lead to performance issues and should be investigated for optimization opportunities.

Related Technology Terms

  • Processor Queue Length
  • Virtual CPU (vCPU)
  • 3

  • Central Processing Unit (CPU) Utilization
  • VMware ESXi
  • CPU Scheduling

Sources for More Information


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