In Some Linux hosts when tunning "top" command you may notice that CPU utilization fo some processes may be showing more than 100%. For e.g. refer to below screenshot, we see CPU% show as 104% for one process.
The question many would be wondering is how is it possible that CPU percentage is shown more than 100% for few processes. Let us drilldown on this. It is expected to see more than 100% CPU Utilization on multi-threaded processes (like WebLogic) running on multi-core CPU systems. This does not mean there is actually a high CPU issue which will cause problems or performance issues. Top output actually shows the total sum of CPU usages (instead of average) across different cores. For e.g. in a multi core system of 4 cores, if there is a process with CPU usage of 30% on all cores, top output shows total sum of CPU as 120% (30+30+30+30=120% as opposed to 30% which is average). This is expected and does not indicate any issues.
The question many would be wondering is how is it possible that CPU percentage is shown more than 100% for few processes. Let us drilldown on this. It is expected to see more than 100% CPU Utilization on multi-threaded processes (like WebLogic) running on multi-core CPU systems. This does not mean there is actually a high CPU issue which will cause problems or performance issues. Top output actually shows the total sum of CPU usages (instead of average) across different cores. For e.g. in a multi core system of 4 cores, if there is a process with CPU usage of 30% on all cores, top output shows total sum of CPU as 120% (30+30+30+30=120% as opposed to 30% which is average). This is expected and does not indicate any issues.
Products to which Article Applies
All Linux Operating SystemsAdditional Reference
tarun boyella
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