Introduce min, average, and standard deviation for the number of
executing mutating and readOnly requests.
Introduce min, max, average, and standard deviation for the number
waiting and number waiting per priority level.
Later:
Revised to use a series of windows
Use three individuals instead of array of powers
Later:
Add coarse queue count metrics, removed windowed avg and stddev
Add metrics for number of queued mutating and readOnly requests,
to complement metrics for number executing.
Later:
Removed windowed average and standard deviation because consumers can
derive such from integrals of consumer's chosen window.
Also replaced "requestKind" Prometheus label with "request_kind".
Later:
Revised to focus on sampling
Make the clock intrinsic to a TimedObserver
... so that the clock can be read while holding the observer's lock;
otherwise, forward progress is not guaranteed (and violations were
observed in testing).
Bug fixes and histogram buckets revision
SetX1 to 1 when queue length limit is zero, beause dividing by zero is nasty.
Remove obsolete argument in gen_test.go.
Add a bucket boundary at 0 for sample-and-water-mark histograms, to
distinguish zeroes from non-zeros.
This includes adding Integrator test.
Simplified test code.
More pervasively used "ctlr" instead of "ctl" as abbreviation for
"controller".
Kubernetes-commit: 57ecea22296797a93b0157169db0ff2e477f58d0
So that errors can be detected before resolving concurrency shares
into concurrency counts.
Kubernetes-commit: 1e170637c3ce6c4ccd378275d9e52192f4be12b7
(1) Replaced random-looking assortment of counter increments and
decrements with something hopefully more principalled-looking. Most
importantly, introduced the MutablePromise abstraction to neatly wrap
up the complicated business of unioning multiple sources of
unblocking.
(2) Improved debug logging.
(3) Somewhat more interesting test cases, and a bug fix wrt round
robin index.
Kubernetes-commit: 1c31b2bdc65377f502c2306dbdf32a802eb1afb7
Mike Spreitzer