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High “hi” and “si” values are also indicators of intensive I/O process. If you see the CPU is busy 100% of the time, but is busy more than say 70% of time in the “wa” state, then the likely cause of the issue is an I/O problem. st : time stolen from this vm by the hypervisor.si : time spent servicing software interrupts
.hi : time spent servicing hardware interrupts
       Â.wa, IO-wait : time waiting for I/O completion.ni, nice   : time running niced user processes.sy, system : time running kernel processes.us, user   : time running un-niced user processes
.Note: Where two labels are shown below, those for more recent kernel versions are shown first.
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The said line contains the following labeled information: Pay attention to the line that shows CPU state percentages based on the interval since the last refresh. You can opt to sort the processes by the different available information labels in the table.Īn interesting section of the top command output is the header portion, which shows the CPU statistics. It then updates this list every three (3) seconds. By default, it sorts the process list and displays the most CPU-intensive tasks running on the server in descending order. The top command displays CPU utilization and which processes may be causing the problem.

Load averages are not normalized for the number of CPUs in a system, so a load average of one (1) means a single CPU system is loaded all the time while on a four (4) CPU system, it means it was idle 75% of the time. The averages are taken over the three (3) time intervals. A process in uninterruptable state is waiting for some I/O access, e.g. A process in a runnable state is either using the CPU or waiting to use the CPU. System load averages is the average number of processes that are either in a runnable or uninterruptable state. System load averages in the past 1, 5, or 15 minutes
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Uptime gives a one-line display of the following information: Usefu l commands for performance analysis When you do performance analysis, always look at the system as a whole, taking care to inspect all subsystems because there may be a cascade effect trickling down that is causing the issue. However, high CPU utilization does not always mean that the CPU is doing work it could also be waiting on another subsystem. It is also usually a source of performance bottlenecks. The CPU is critical in servers used mainly for applications and databases. (Is your server not living up to its potential? Order a server from us with promo code PACKETS for 15% off your first invoice)