pmAddDerivedMetric(3) on Linux
The text f65c83adf57b, as Debian 12 (Bookworm), Debian 11 (Bullseye) shipped it.
register a per-context derived metric name and definition
The text f65c83adf57b, as Debian 12 (Bookworm), Debian 11 (Bullseye) shipped it.
register a per-context derived metric name and definition