Describe the enhancement:

Since 4.2, Linux exposes contention metrics for CPU, Memory, and IO in procfs under the /proc/pressure path for a system as a whole, or for cgroup2 the subdirectory for each cgroup controller in the cgroupfs mount point contains cpu.pressure, memory.pressure, and io.pressure files.

An extra system metricset (perhaps called psi?) that collects these metrics on a defined interval would be extremely useful, both for specific cgroups and for systems as a whole.

Further Reading:

• https://www.kernel.org/doc/html/latest/accounting/psi.html
• https://lwn.net/Articles/759658/
• https://facebookmicrosites.github.io/psi/docs/overview.html