Adding upstream version 1.21.8.upstream/1.21.8

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 400 insertions, 0 deletions

diff --git a/src/runtime/metrics/doc.go b/src/runtime/metrics/doc.go
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+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Note: run 'go generate' (which will run 'go test -generate') to update the "Supported metrics" list.
+//go:generate go test -run=Docs -generate
+
+/*
+Package metrics provides a stable interface to access implementation-defined
+metrics exported by the Go runtime. This package is similar to existing functions
+like [runtime.ReadMemStats] and [debug.ReadGCStats], but significantly more general.
+
+The set of metrics defined by this package may evolve as the runtime itself
+evolves, and also enables variation across Go implementations, whose relevant
+metric sets may not intersect.
+
+# Interface
+
+Metrics are designated by a string key, rather than, for example, a field name in
+a struct. The full list of supported metrics is always available in the slice of
+Descriptions returned by All. Each Description also includes useful information
+about the metric.
+
+Thus, users of this API are encouraged to sample supported metrics defined by the
+slice returned by All to remain compatible across Go versions. Of course, situations
+arise where reading specific metrics is critical. For these cases, users are
+encouraged to use build tags, and although metrics may be deprecated and removed,
+users should consider this to be an exceptional and rare event, coinciding with a
+very large change in a particular Go implementation.
+
+Each metric key also has a "kind" that describes the format of the metric's value.
+In the interest of not breaking users of this package, the "kind" for a given metric
+is guaranteed not to change. If it must change, then a new metric will be introduced
+with a new key and a new "kind."
+
+# Metric key format
+
+As mentioned earlier, metric keys are strings. Their format is simple and well-defined,
+designed to be both human and machine readable. It is split into two components,
+separated by a colon: a rooted path and a unit. The choice to include the unit in
+the key is motivated by compatibility: if a metric's unit changes, its semantics likely
+did also, and a new key should be introduced.
+
+For more details on the precise definition of the metric key's path and unit formats, see
+the documentation of the Name field of the Description struct.
+
+# A note about floats
+
+This package supports metrics whose values have a floating-point representation. In
+order to improve ease-of-use, this package promises to never produce the following
+classes of floating-point values: NaN, infinity.
+
+# Supported metrics
+
+Below is the full list of supported metrics, ordered lexicographically.
+
+	/cgo/go-to-c-calls:calls
+		Count of calls made from Go to C by the current process.
+
+	/cpu/classes/gc/mark/assist:cpu-seconds
+		Estimated total CPU time goroutines spent performing GC
+		tasks to assist the GC and prevent it from falling behind the
+		application. This metric is an overestimate, and not directly
+		comparable to system CPU time measurements. Compare only with
+		other /cpu/classes metrics.
+
+	/cpu/classes/gc/mark/dedicated:cpu-seconds
+		Estimated total CPU time spent performing GC tasks on processors
+		(as defined by GOMAXPROCS) dedicated to those tasks. This metric
+		is an overestimate, and not directly comparable to system CPU
+		time measurements. Compare only with other /cpu/classes metrics.
+
+	/cpu/classes/gc/mark/idle:cpu-seconds
+		Estimated total CPU time spent performing GC tasks on spare CPU
+		resources that the Go scheduler could not otherwise find a use
+		for. This should be subtracted from the total GC CPU time to
+		obtain a measure of compulsory GC CPU time. This metric is an
+		overestimate, and not directly comparable to system CPU time
+		measurements. Compare only with other /cpu/classes metrics.
+
+	/cpu/classes/gc/pause:cpu-seconds
+		Estimated total CPU time spent with the application paused by
+		the GC. Even if only one thread is running during the pause,
+		this is computed as GOMAXPROCS times the pause latency because
+		nothing else can be executing. This is the exact sum of samples
+		in /gc/pause:seconds if each sample is multiplied by GOMAXPROCS
+		at the time it is taken. This metric is an overestimate,
+		and not directly comparable to system CPU time measurements.
+		Compare only with other /cpu/classes metrics.
+
+	/cpu/classes/gc/total:cpu-seconds
+		Estimated total CPU time spent performing GC tasks. This metric
+		is an overestimate, and not directly comparable to system CPU
+		time measurements. Compare only with other /cpu/classes metrics.
+		Sum of all metrics in /cpu/classes/gc.
+
+	/cpu/classes/idle:cpu-seconds
+		Estimated total available CPU time not spent executing
+		any Go or Go runtime code. In other words, the part of
+		/cpu/classes/total:cpu-seconds that was unused. This metric is
+		an overestimate, and not directly comparable to system CPU time
+		measurements. Compare only with other /cpu/classes metrics.
+
+	/cpu/classes/scavenge/assist:cpu-seconds
+		Estimated total CPU time spent returning unused memory to the
+		underlying platform in response eagerly in response to memory
+		pressure. This metric is an overestimate, and not directly
+		comparable to system CPU time measurements. Compare only with
+		other /cpu/classes metrics.
+
+	/cpu/classes/scavenge/background:cpu-seconds
+		Estimated total CPU time spent performing background tasks to
+		return unused memory to the underlying platform. This metric is
+		an overestimate, and not directly comparable to system CPU time
+		measurements. Compare only with other /cpu/classes metrics.
+
+	/cpu/classes/scavenge/total:cpu-seconds
+		Estimated total CPU time spent performing tasks that return
+		unused memory to the underlying platform. This metric is an
+		overestimate, and not directly comparable to system CPU time
+		measurements. Compare only with other /cpu/classes metrics.
+		Sum of all metrics in /cpu/classes/scavenge.
+
+	/cpu/classes/total:cpu-seconds
+		Estimated total available CPU time for user Go code or the Go
+		runtime, as defined by GOMAXPROCS. In other words, GOMAXPROCS
+		integrated over the wall-clock duration this process has been
+		executing for. This metric is an overestimate, and not directly
+		comparable to system CPU time measurements. Compare only with
+		other /cpu/classes metrics. Sum of all metrics in /cpu/classes.
+
+	/cpu/classes/user:cpu-seconds
+		Estimated total CPU time spent running user Go code. This may
+		also include some small amount of time spent in the Go runtime.
+		This metric is an overestimate, and not directly comparable
+		to system CPU time measurements. Compare only with other
+		/cpu/classes metrics.
+
+	/gc/cycles/automatic:gc-cycles
+		Count of completed GC cycles generated by the Go runtime.
+
+	/gc/cycles/forced:gc-cycles
+		Count of completed GC cycles forced by the application.
+
+	/gc/cycles/total:gc-cycles
+		Count of all completed GC cycles.
+
+	/gc/gogc:percent
+		Heap size target percentage configured by the user, otherwise
+		100. This value is set by the GOGC environment variable, and the
+		runtime/debug.SetGCPercent function.
+
+	/gc/gomemlimit:bytes
+		Go runtime memory limit configured by the user, otherwise
+		math.MaxInt64. This value is set by the GOMEMLIMIT environment
+		variable, and the runtime/debug.SetMemoryLimit function.
+
+	/gc/heap/allocs-by-size:bytes
+		Distribution of heap allocations by approximate size.
+		Bucket counts increase monotonically. Note that this does not
+		include tiny objects as defined by /gc/heap/tiny/allocs:objects,
+		only tiny blocks.
+
+	/gc/heap/allocs:bytes
+		Cumulative sum of memory allocated to the heap by the
+		application.
+
+	/gc/heap/allocs:objects
+		Cumulative count of heap allocations triggered by the
+		application. Note that this does not include tiny objects as
+		defined by /gc/heap/tiny/allocs:objects, only tiny blocks.
+
+	/gc/heap/frees-by-size:bytes
+		Distribution of freed heap allocations by approximate size.
+		Bucket counts increase monotonically. Note that this does not
+		include tiny objects as defined by /gc/heap/tiny/allocs:objects,
+		only tiny blocks.
+
+	/gc/heap/frees:bytes
+		Cumulative sum of heap memory freed by the garbage collector.
+
+	/gc/heap/frees:objects
+		Cumulative count of heap allocations whose storage was freed
+		by the garbage collector. Note that this does not include tiny
+		objects as defined by /gc/heap/tiny/allocs:objects, only tiny
+		blocks.
+
+	/gc/heap/goal:bytes
+		Heap size target for the end of the GC cycle.
+
+	/gc/heap/live:bytes
+		Heap memory occupied by live objects that were marked by the
+		previous GC.
+
+	/gc/heap/objects:objects
+		Number of objects, live or unswept, occupying heap memory.
+
+	/gc/heap/tiny/allocs:objects
+		Count of small allocations that are packed together into blocks.
+		These allocations are counted separately from other allocations
+		because each individual allocation is not tracked by the
+		runtime, only their block. Each block is already accounted for
+		in allocs-by-size and frees-by-size.
+
+	/gc/limiter/last-enabled:gc-cycle
+		GC cycle the last time the GC CPU limiter was enabled.
+		This metric is useful for diagnosing the root cause of an
+		out-of-memory error, because the limiter trades memory for CPU
+		time when the GC's CPU time gets too high. This is most likely
+		to occur with use of SetMemoryLimit. The first GC cycle is cycle
+		1, so a value of 0 indicates that it was never enabled.
+
+	/gc/pauses:seconds
+		Distribution of individual GC-related stop-the-world pause
+		latencies. Bucket counts increase monotonically.
+
+	/gc/scan/globals:bytes
+		The total amount of global variable space that is scannable.
+
+	/gc/scan/heap:bytes
+		The total amount of heap space that is scannable.
+
+	/gc/scan/stack:bytes
+		The number of bytes of stack that were scanned last GC cycle.
+
+	/gc/scan/total:bytes
+		The total amount space that is scannable. Sum of all metrics in
+		/gc/scan.
+
+	/gc/stack/starting-size:bytes
+		The stack size of new goroutines.
+
+	/godebug/non-default-behavior/execerrdot:events
+		The number of non-default behaviors executed by the os/exec
+		package due to a non-default GODEBUG=execerrdot=... setting.
+
+	/godebug/non-default-behavior/gocachehash:events
+		The number of non-default behaviors executed by the cmd/go
+		package due to a non-default GODEBUG=gocachehash=... setting.
+
+	/godebug/non-default-behavior/gocachetest:events
+		The number of non-default behaviors executed by the cmd/go
+		package due to a non-default GODEBUG=gocachetest=... setting.
+
+	/godebug/non-default-behavior/gocacheverify:events
+		The number of non-default behaviors executed by the cmd/go
+		package due to a non-default GODEBUG=gocacheverify=... setting.
+
+	/godebug/non-default-behavior/http2client:events
+		The number of non-default behaviors executed by the net/http
+		package due to a non-default GODEBUG=http2client=... setting.
+
+	/godebug/non-default-behavior/http2server:events
+		The number of non-default behaviors executed by the net/http
+		package due to a non-default GODEBUG=http2server=... setting.
+
+	/godebug/non-default-behavior/installgoroot:events
+		The number of non-default behaviors executed by the go/build
+		package due to a non-default GODEBUG=installgoroot=... setting.
+
+	/godebug/non-default-behavior/jstmpllitinterp:events
+		The number of non-default behaviors executed by
+		the html/template package due to a non-default
+		GODEBUG=jstmpllitinterp=... setting.
+
+	/godebug/non-default-behavior/multipartmaxheaders:events
+		The number of non-default behaviors executed by
+		the mime/multipart package due to a non-default
+		GODEBUG=multipartmaxheaders=... setting.
+
+	/godebug/non-default-behavior/multipartmaxparts:events
+		The number of non-default behaviors executed by
+		the mime/multipart package due to a non-default
+		GODEBUG=multipartmaxparts=... setting.
+
+	/godebug/non-default-behavior/multipathtcp:events
+		The number of non-default behaviors executed by the net package
+		due to a non-default GODEBUG=multipathtcp=... setting.
+
+	/godebug/non-default-behavior/panicnil:events
+		The number of non-default behaviors executed by the runtime
+		package due to a non-default GODEBUG=panicnil=... setting.
+
+	/godebug/non-default-behavior/randautoseed:events
+		The number of non-default behaviors executed by the math/rand
+		package due to a non-default GODEBUG=randautoseed=... setting.
+
+	/godebug/non-default-behavior/tarinsecurepath:events
+		The number of non-default behaviors executed by the archive/tar
+		package due to a non-default GODEBUG=tarinsecurepath=...
+		setting.
+
+	/godebug/non-default-behavior/tlsmaxrsasize:events
+		The number of non-default behaviors executed by the crypto/tls
+		package due to a non-default GODEBUG=tlsmaxrsasize=... setting.
+
+	/godebug/non-default-behavior/x509sha1:events
+		The number of non-default behaviors executed by the crypto/x509
+		package due to a non-default GODEBUG=x509sha1=... setting.
+
+	/godebug/non-default-behavior/x509usefallbackroots:events
+		The number of non-default behaviors executed by the crypto/x509
+		package due to a non-default GODEBUG=x509usefallbackroots=...
+		setting.
+
+	/godebug/non-default-behavior/zipinsecurepath:events
+		The number of non-default behaviors executed by the archive/zip
+		package due to a non-default GODEBUG=zipinsecurepath=...
+		setting.
+
+	/memory/classes/heap/free:bytes
+		Memory that is completely free and eligible to be returned to
+		the underlying system, but has not been. This metric is the
+		runtime's estimate of free address space that is backed by
+		physical memory.
+
+	/memory/classes/heap/objects:bytes
+		Memory occupied by live objects and dead objects that have not
+		yet been marked free by the garbage collector.
+
+	/memory/classes/heap/released:bytes
+		Memory that is completely free and has been returned to the
+		underlying system. This metric is the runtime's estimate of free
+		address space that is still mapped into the process, but is not
+		backed by physical memory.
+
+	/memory/classes/heap/stacks:bytes
+		Memory allocated from the heap that is reserved for stack space,
+		whether or not it is currently in-use. Currently, this
+		represents all stack memory for goroutines. It also includes all
+		OS thread stacks in non-cgo programs. Note that stacks may be
+		allocated differently in the future, and this may change.
+
+	/memory/classes/heap/unused:bytes
+		Memory that is reserved for heap objects but is not currently
+		used to hold heap objects.
+
+	/memory/classes/metadata/mcache/free:bytes
+		Memory that is reserved for runtime mcache structures, but not
+		in-use.
+
+	/memory/classes/metadata/mcache/inuse:bytes
+		Memory that is occupied by runtime mcache structures that are
+		currently being used.
+
+	/memory/classes/metadata/mspan/free:bytes
+		Memory that is reserved for runtime mspan structures, but not
+		in-use.
+
+	/memory/classes/metadata/mspan/inuse:bytes
+		Memory that is occupied by runtime mspan structures that are
+		currently being used.
+
+	/memory/classes/metadata/other:bytes
+		Memory that is reserved for or used to hold runtime metadata.
+
+	/memory/classes/os-stacks:bytes
+		Stack memory allocated by the underlying operating system.
+		In non-cgo programs this metric is currently zero. This may
+		change in the future.In cgo programs this metric includes
+		OS thread stacks allocated directly from the OS. Currently,
+		this only accounts for one stack in c-shared and c-archive build
+		modes, and other sources of stacks from the OS are not measured.
+		This too may change in the future.
+
+	/memory/classes/other:bytes
+		Memory used by execution trace buffers, structures for debugging
+		the runtime, finalizer and profiler specials, and more.
+
+	/memory/classes/profiling/buckets:bytes
+		Memory that is used by the stack trace hash map used for
+		profiling.
+
+	/memory/classes/total:bytes
+		All memory mapped by the Go runtime into the current process
+		as read-write. Note that this does not include memory mapped
+		by code called via cgo or via the syscall package. Sum of all
+		metrics in /memory/classes.
+
+	/sched/gomaxprocs:threads
+		The current runtime.GOMAXPROCS setting, or the number of
+		operating system threads that can execute user-level Go code
+		simultaneously.
+
+	/sched/goroutines:goroutines
+		Count of live goroutines.
+
+	/sched/latencies:seconds
+		Distribution of the time goroutines have spent in the scheduler
+		in a runnable state before actually running. Bucket counts
+		increase monotonically.
+
+	/sync/mutex/wait/total:seconds
+		Approximate cumulative time goroutines have spent blocked
+		on a sync.Mutex or sync.RWMutex. This metric is useful for
+		identifying global changes in lock contention. Collect a mutex
+		or block profile using the runtime/pprof package for more
+		detailed contention data.
+*/
+package metrics