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High CPU utilization on only one CPU out of 4 CPUs

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http://feedproxy.google.com – Hi all, I am doing some high load testing on my Linux OS - 4 CPU box. I observe that all CPUs are at ~20% utilization except CPU-1 which is 50% CPU utilization. From sar command I came to know there are total 3000 interrupts/s happening in system. And all there interrupts are under "i050/s" column and are bound to to CPU-1. Below is the sar output: 04:57:40 CPU i000/s i003/s i008/s i009/s i014/s i050/s 04:57:50 0 12.09 0.00 0.00 0.00 0.00 0.00 04:57:50 1 0.00 0.00 0.00 0.00 0.00 2562.94 04:57:50 2 87.91 0.00 0.00 0.00 0.00 0.00 04:57:50 3 0.00 0.00 0.00 0.00 0.00 0.00 Now the "cat /proc/interrupt" output shows that most of these interrupts are coming from "eth4" Now below are my questions: 1. What is this i050/s means? 2. Why are they so many interrupts coming from eth4? 3. Why are they always uses CPU-1? Is there any way I can distribute load to other CPUs? (HowTos)