Documentation/accounting/psi.rst

4 PSI - Pressure Stall Information
14 either play it safe and under-utilize their hardware resources, or
23 scarcity aids users in sizing workloads to hardware--or provisioning
38 respective file in /proc/pressure/ -- cpu, memory, and io.
52 The "full" line indicates the share of time in which all non-idle
75 time window, e.g. 100ms of total stall time within any 500ms window to
87 would add 150ms threshold for partial memory stall measured within
89 would add 50ms threshold for full io stall measured within 1sec time window.
103 The kernel accepts window sizes ranging from 500ms to 10s, therefore min
104 monitoring update interval is 50ms and max is 1s. Min limit is set to
109 When activated, psi monitor stays active for at least the duration of one
113 Notifications to the userspace are rate-limited to one per tracking window.
115 The trigger will de-register when the file descriptor used to define the
118 Userspace monitor usage example
131    * Monitor memory partial stall with 1s tracking window size
132    * and 150ms threshold.
155 		n = poll(&fds, 1, -1);
184 Per-cgroup psi monitors can be specified and used the same way as
185 system-wide ones.