CPU usage displays misleading high values during periods of heavy IO activity (Doc ID 2053893.1)

Last updated on SEPTEMBER 28, 2015

Applies to:

Oracle JRockit - Version R28 to R28 [Release JRockit]
Generic Linux

Symptoms

On Linux kernels 2.6 and later, JRockit would include time spent waiting for IO completion as "CPU usage". During periods of heavy IO activity, this could result in misleading high values reported as CPU consumption in various tools like Flight Recorder, performance counters, and the cpuload diagnostic command. 

Cause

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