Resource Pressure

Linux PSI Separates Partial and Total Resource Stalls

A Linux host can report modest CPU utilization while runnable work is delayed, or ample memory capacity while tasks repeatedly stall in reclaim. Utilization counters describe resource activity; pressure stall information records time in which work cannot make progress because a resource is contended. PSI exposes that lost execution opportunity through CPU, memory, and I/O pressure files. Its central distinction is between a stall affecting at least one task and a stall that leaves every non-idle task unable to make progress.