Introduce stats(3), a flexible statistics gathering API.
This provides a framework to define a template describing
a set of "variables of interest" and the intended way for the
framework to maintain them (for example the maximum, sum,
t-digest, or a combination thereof). Afterwards the user
code feeds in the raw data, and the framework maintains
these variables inside a user-provided, opaque stats blobs.
The framework also provides a way to selectively extract the
stats from the blobs. The stats(3) framework can be used in
both userspace and the kernel.
See the stats(3) manual page for details.
This will be used by the upcoming TCP statistics gathering code,
This depends on both the ARB tree macros:
and the Q math macros:
The stats(3) framework is disabled by default for now,
except in the NOTES kernel (for QA); it is expected
to be enabled in amd64 GENERIC after a cool down period.
Sponsored By: Klara Inc, Netflix
Obtained from: Netflix