NOTE
vmstat
Sampling runnable/blocked tasks, memory, paging, block I/O, interrupts, context switches, and CPU states.
This is a historical learning note and may contain outdated or incomplete understanding.
vmstat summarizes process queues, memory, paging/swap activity, block I/O, interrupts, context switches, and CPU-state percentages over sampling intervals.
Use repeated interval samples. Active swap-in/swap-out can indicate memory pressure, while merely having swap space allocated does not mean the system is currently thrashing. A high runnable queue suggests CPU demand, but interpret it together with CPU utilization, stealing, I/O waits, and workload characteristics.