26.12.11

Understanding CPU Utilization


  • Utilization
Utilization is a statistical concept (Queueing Theory) as well as a primary business measure for the rental industry.

  • CPU load vs. CPU utilization
The comparative study of different load indices carried out by Ferrari et al.[1] reported that CPU load information based upon the CPU queue length does much better in load balancing compared to CPU utilization. The reason CPU queue length did better is probably because when a host is heavily loaded, its CPU utilization is likely to be close to 100% and it is unable to reflect the exact load level of the utilization. In contrast, CPU queue lengths can directly reflect the amount of load on a CPU. As an example, two systems, one with 3 and the other with 6 processes in the queue, will probably have utilizations close to 100% although they obviously differ.

  • High CPU Utilization in Windows

This month, I show you how to troubleshoot situations in which your server is sluggish or unresponsive because of high CPU utilization. When a server's CPU or CPUs are working at or above 80 percent to 90 percent utilization, applications on the server can become sluggish or stop responding completely. When this situation occurs, you need to determine which process is monopolizing the CPUs.

  • PC Guide - CPU Utilization
CPU utilization is one of those performance factors that is both grossly underrated and overrated at the same time. :^) Most people have never even heard of it; it often seems though that a big percentage of those who do understand its role worry about it way too much. :^) Like most performance issues, sweating small differences in numbers is usually pointless; it doesn't matter much if your CPU utilization is 5% or 10%; but if it is 80% or 90% then you are going to see an impact on the usability of the system if you multitask.

  • Windows Server Performance Team Blog - Interpreting CPU Utilization for Performance Analysis
CPU hardware and features are rapidly evolving, and your performance testing and analysis methodologies may need to evolve as well. If you rely on CPU utilization as a crucial performance metric, you could be making some big mistakes interpreting the data. Read this post to get the full scoop; experts can scroll down to the end of the article for a summary of the key points.

  • IBM Informix Dynamic Server Performance Guide - CPU Utilization
You can use the resource-utilization formula from the previous section to estimate the response time for a heavily loaded CPU. However, high utilization for the CPU does not always indicate a performance problem. The CPU performs all calculations that are needed to process transactions. The more transaction-related calculations that it performs within a given period, the higher the throughput will be for that period. As long as transaction throughput is high and seems to remain proportional to CPUutilization, a high CPU utilization indicates that the computer is being used to the fullest advantage.

  • How do I Find out Linux CPU Utilization
You can see Linux CPU utilization under CPU stats. The task’s share of the elapsed CPU time since the last screen update, expressed as a percentage of total CPU time. In a true SMP environment (multiple CPUS), top will operate in number of CPUs. Please note that you need to type q key to exit the top command display.

Please note that you need to install special package called sysstat to take advantage of following commands. This package includes system performance tools for Linux (Red Hat Linux / RHEL includes these tools by default).


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