OneClick Tomcat process using 100% CPU regardless of OneClick load
Article ID: 373729
Updated On:
Products
Issue/Introduction
You see poor tomcat performance and high CPU. Documented requirements are already met and verified for
1. Dedicated Tomcat memory is more than sufficient
2. Server RAM is high enough to support the max number of concurrent webapp clients.
Both of the above are known causes of high CPU and have been ruled out. No other problems are seen on Oneclick.
After a Tomcat restart the CPU normalizes but climbs continuously until all cores are using 100%. Tomcat memory usage is also affected and climbs in a similar manner but does not use all of the Tomcat memory.
Environment
This was seen on Windows servers but may occur on Linux also.
Cause
The OneClick CPU was high due to poor SpectroSERVER performance.
An analysis of the SpectroSERVERs monitored by this OneClick revealed one where performance was poor due to insufficient RAM. Workload had increased on that one SpectroSERVER but resources had not been increased to meet the new load.
We can imagine the OC is polling the SpectroSERVER for information and those requests are very slow in coming back as the SpectroSERVER is unresponsive due to low resources. So the thread remains opened with the SpectroSERVER, until it finally is returned. This uses up clock cycles on OC, and as they are not released back to the CPU quickly, the load builds up until all threads are occupied with requests that are waiting to be responded by the SpectroSERVER.
Resolution
Ensure that the SpectroiSERVERs have sufficient RAM for healthy OneClick performance. Once this was addressed the problem went away.
Additional Information
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