metrics(指标数据)

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 key格式

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 支持的指标

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
	includes time spent with the world stopped due to the GC. 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/heap/allocs-by-size:bytes
	Distribution of heap allocations by approximate size.
	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.
	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/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 individual GC-related stop-the-world pause
	latencies.

/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/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/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/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.

/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.

/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.

/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.