7.7. Symptoms of a CPU Bottleneck

What are the symptoms of a CPU bottleneck? The four major areas are:

  • Saturation of CPU

  • Large queues

  • Resource starvation

  • User dissatisfaction with the system

7.7.1. Saturation

Saturation may be indicated by the following:

  • Zero idle CPU

  • A high percentage of user CPU usage

  • A high percentage of system CPU usage

In the case of high system CPU usage, memory management, I/O management, and SMP kernel contention involving spinlocks may cause false symptoms of saturation. Real causes of CPU saturation from heavy system CPU usage are:

  • A heavy IPC system call rate

  • Heavy termio load

  • Evidence of process creation

  • Heavy network traffic

  • An SMP kernel contention, but only if caused by a user process

7.7.2. Expensive CPU Utilization

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