Linux › Section H · Processes and resource utilization › Topic H.5
Resource monitoring: CPU, memory, and I/O
Processes compete for three hardware resources: processor time, memory and input/output. A handful of standard tools show how the kernel is sharing them out, and reading their numbers correctly is the first step in explaining why a system feels slow.
In this topic
- Measure before you change anything
- CPU time: user, system and real
- Scheduling and nice values
- Load averages
- Worked example: reading uptime
- Memory: pages, faults and free
- vmstat: the whole system over time
- The out-of-memory killer
- Disk I/O: iostat, iotop and ionice
- Worked example: per-process figures with pidstat
- Common mistakes to avoid
- Key takeaways
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