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diff --git a/devdocs/go/runtime%2Fmetrics%2Findex.html b/devdocs/go/runtime%2Fmetrics%2Findex.html new file mode 100644 index 00000000..b26400d7 --- /dev/null +++ b/devdocs/go/runtime%2Fmetrics%2Findex.html @@ -0,0 +1,618 @@ +<h1> Package metrics </h1> <ul id="short-nav"> +<li><code>import "runtime/metrics"</code></li> +<li><a href="#pkg-overview" class="overviewLink">Overview</a></li> +<li><a href="#pkg-index" class="indexLink">Index</a></li> +<li><a href="#pkg-examples" class="examplesLink">Examples</a></li> +</ul> <h2 id="pkg-overview">Overview </h2> <p>Package metrics provides a stable interface to access implementation-defined metrics exported by the Go runtime. This package is similar to existing functions like <span>runtime.ReadMemStats</span> and <span>runtime/debug.ReadGCStats</span>, but significantly more general. </p> +<p>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. </p> +<h3 id="hdr-Interface">Interface</h3> <p>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 <a href="#All">All</a>. Each <a href="#Description">Description</a> also includes useful information about the metric. </p> +<p>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. </p> +<p>Each metric key also has a "kind" (see <a href="#ValueKind">ValueKind</a>) 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." </p> +<h3 id="hdr-Metric_key_format">Metric key format</h3> <p>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. </p> +<p>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. </p> +<h3 id="hdr-A_note_about_floats">A note about floats</h3> <p>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. </p> +<h3 id="hdr-Supported_metrics">Supported metrics</h3> <p>Below is the full list of supported metrics, ordered lexicographically. </p> +<pre data-language="go">/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 /sched/pauses/total/gc: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 + Deprecated. Prefer the identical /sched/pauses/total/gc:seconds. + +/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/gotypesalias:events + The number of non-default behaviors executed by the go/types + package due to a non-default GODEBUG=gotypesalias=... 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/httplaxcontentlength:events + The number of non-default behaviors executed by the net/http + package due to a non-default GODEBUG=httplaxcontentlength=... + setting. + +/godebug/non-default-behavior/httpmuxgo121:events + The number of non-default behaviors executed by the net/http + package due to a non-default GODEBUG=httpmuxgo121=... 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/tls10server:events + The number of non-default behaviors executed by the crypto/tls + package due to a non-default GODEBUG=tls10server=... 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/tlsrsakex:events + The number of non-default behaviors executed by the crypto/tls + package due to a non-default GODEBUG=tlsrsakex=... setting. + +/godebug/non-default-behavior/tlsunsafeekm:events + The number of non-default behaviors executed by the crypto/tls + package due to a non-default GODEBUG=tlsunsafeekm=... 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/x509usepolicies:events + The number of non-default behaviors executed by the crypto/x509 + package due to a non-default GODEBUG=x509usepolicies=... + 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. + +/sched/pauses/stopping/gc:seconds + Distribution of individual GC-related stop-the-world stopping + latencies. This is the time it takes from deciding to stop the + world until all Ps are stopped. This is a subset of the total + GC-related stop-the-world time (/sched/pauses/total/gc:seconds). + During this time, some threads may be executing. Bucket counts + increase monotonically. + +/sched/pauses/stopping/other:seconds + Distribution of individual non-GC-related stop-the-world + stopping latencies. This is the time it takes from deciding + to stop the world until all Ps are stopped. This is a + subset of the total non-GC-related stop-the-world time + (/sched/pauses/total/other:seconds). During this time, some + threads may be executing. Bucket counts increase monotonically. + +/sched/pauses/total/gc:seconds + Distribution of individual GC-related stop-the-world pause + latencies. This is the time from deciding to stop the world + until the world is started again. Some of this time is spent + getting all threads to stop (this is measured directly in + /sched/pauses/stopping/gc:seconds), during which some threads + may still be running. Bucket counts increase monotonically. + +/sched/pauses/total/other:seconds + Distribution of individual non-GC-related stop-the-world + pause latencies. This is the time from deciding to stop the + world until the world is started again. Some of this time + is spent getting all threads to stop (measured directly in + /sched/pauses/stopping/other:seconds). Bucket counts increase + monotonically. + +/sync/mutex/wait/total:seconds + Approximate cumulative time goroutines have spent blocked on a + sync.Mutex, sync.RWMutex, or runtime-internal lock. 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. +</pre> <h2 id="pkg-index">Index </h2> <ul id="manual-nav"> +<li><a href="#Read">func Read(m []Sample)</a></li> +<li><a href="#Description">type Description</a></li> +<li> <a href="#All">func All() []Description</a> +</li> +<li><a href="#Float64Histogram">type Float64Histogram</a></li> +<li><a href="#Sample">type Sample</a></li> +<li><a href="#Value">type Value</a></li> +<li> <a href="#Value.Float64">func (v Value) Float64() float64</a> +</li> +<li> <a href="#Value.Float64Histogram">func (v Value) Float64Histogram() *Float64Histogram</a> +</li> +<li> <a href="#Value.Kind">func (v Value) Kind() ValueKind</a> +</li> +<li> <a href="#Value.Uint64">func (v Value) Uint64() uint64</a> +</li> +<li><a href="#ValueKind">type ValueKind</a></li> +</ul> <div id="pkg-examples"> <h3>Examples</h3> <dl> <dd><a class="exampleLink" href="#example_Read_readingAllMetrics">Read (ReadingAllMetrics)</a></dd> <dd><a class="exampleLink" href="#example_Read_readingOneMetric">Read (ReadingOneMetric)</a></dd> </dl> </div> <h3>Package files</h3> <p> <span>description.go</span> <span>doc.go</span> <span>histogram.go</span> <span>sample.go</span> <span>value.go</span> </p> <h2 id="Read">func <span>Read</span> <span title="Added in Go 1.16">1.16</span> </h2> <pre data-language="go">func Read(m []Sample)</pre> <p>Read populates each <a href="#Value">Value</a> field in the given slice of metric samples. </p> +<p>Desired metrics should be present in the slice with the appropriate name. The user of this API is encouraged to re-use the same slice between calls for efficiency, but is not required to do so. </p> +<p>Note that re-use has some caveats. Notably, Values should not be read or manipulated while a Read with that value is outstanding; that is a data race. This property includes pointer-typed Values (for example, <a href="#Float64Histogram">Float64Histogram</a>) whose underlying storage will be reused by Read when possible. To safely use such values in a concurrent setting, all data must be deep-copied. </p> +<p>It is safe to execute multiple Read calls concurrently, but their arguments must share no underlying memory. When in doubt, create a new []Sample from scratch, which is always safe, though may be inefficient. </p> +<p>Sample values with names not appearing in <a href="#All">All</a> will have their Value populated as KindBad to indicate that the name is unknown. </p> <h4 id="example_Read_readingAllMetrics"> <span class="text">Example (ReadingAllMetrics)</span> +</h4> <p>Code:</p> <pre class="code" data-language="go"> +// Get descriptions for all supported metrics. +descs := metrics.All() + +// Create a sample for each metric. +samples := make([]metrics.Sample, len(descs)) +for i := range samples { + samples[i].Name = descs[i].Name +} + +// Sample the metrics. Re-use the samples slice if you can! +metrics.Read(samples) + +// Iterate over all results. +for _, sample := range samples { + // Pull out the name and value. + name, value := sample.Name, sample.Value + + // Handle each sample. + switch value.Kind() { + case metrics.KindUint64: + fmt.Printf("%s: %d\n", name, value.Uint64()) + case metrics.KindFloat64: + fmt.Printf("%s: %f\n", name, value.Float64()) + case metrics.KindFloat64Histogram: + // The histogram may be quite large, so let's just pull out + // a crude estimate for the median for the sake of this example. + fmt.Printf("%s: %f\n", name, medianBucket(value.Float64Histogram())) + case metrics.KindBad: + // This should never happen because all metrics are supported + // by construction. + panic("bug in runtime/metrics package!") + default: + // This may happen as new metrics get added. + // + // The safest thing to do here is to simply log it somewhere + // as something to look into, but ignore it for now. + // In the worst case, you might temporarily miss out on a new metric. + fmt.Printf("%s: unexpected metric Kind: %v\n", name, value.Kind()) + } +} +</pre> <h4 id="example_Read_readingOneMetric"> <span class="text">Example (ReadingOneMetric)</span> +</h4> <p>Code:</p> <pre class="code" data-language="go"> +// Name of the metric we want to read. +const myMetric = "/memory/classes/heap/free:bytes" + +// Create a sample for the metric. +sample := make([]metrics.Sample, 1) +sample[0].Name = myMetric + +// Sample the metric. +metrics.Read(sample) + +// Check if the metric is actually supported. +// If it's not, the resulting value will always have +// kind KindBad. +if sample[0].Value.Kind() == metrics.KindBad { + panic(fmt.Sprintf("metric %q no longer supported", myMetric)) +} + +// Handle the result. +// +// It's OK to assume a particular Kind for a metric; +// they're guaranteed not to change. +freeBytes := sample[0].Value.Uint64() + +fmt.Printf("free but not released memory: %d\n", freeBytes) +</pre> <h2 id="Description">type <span>Description</span> <span title="Added in Go 1.16">1.16</span> </h2> <p>Description describes a runtime metric. </p> +<pre data-language="go">type Description struct { + // Name is the full name of the metric which includes the unit. + // + // The format of the metric may be described by the following regular expression. + // + // ^(?P<name>/[^:]+):(?P<unit>[^:*/]+(?:[*/][^:*/]+)*)$ + // + // The format splits the name into two components, separated by a colon: a path which always + // starts with a /, and a machine-parseable unit. The name may contain any valid Unicode + // codepoint in between / characters, but by convention will try to stick to lowercase + // characters and hyphens. An example of such a path might be "/memory/heap/free". + // + // The unit is by convention a series of lowercase English unit names (singular or plural) + // without prefixes delimited by '*' or '/'. The unit names may contain any valid Unicode + // codepoint that is not a delimiter. + // Examples of units might be "seconds", "bytes", "bytes/second", "cpu-seconds", + // "byte*cpu-seconds", and "bytes/second/second". + // + // For histograms, multiple units may apply. For instance, the units of the buckets and + // the count. By convention, for histograms, the units of the count are always "samples" + // with the type of sample evident by the metric's name, while the unit in the name + // specifies the buckets' unit. + // + // A complete name might look like "/memory/heap/free:bytes". + Name string + + // Description is an English language sentence describing the metric. + Description string + + // Kind is the kind of value for this metric. + // + // The purpose of this field is to allow users to filter out metrics whose values are + // types which their application may not understand. + Kind ValueKind + + // Cumulative is whether or not the metric is cumulative. If a cumulative metric is just + // a single number, then it increases monotonically. If the metric is a distribution, + // then each bucket count increases monotonically. + // + // This flag thus indicates whether or not it's useful to compute a rate from this value. + Cumulative bool +} +</pre> <h3 id="All">func <span>All</span> <span title="Added in Go 1.16">1.16</span> </h3> <pre data-language="go">func All() []Description</pre> <p>All returns a slice of containing metric descriptions for all supported metrics. </p> +<h2 id="Float64Histogram">type <span>Float64Histogram</span> <span title="Added in Go 1.16">1.16</span> </h2> <p>Float64Histogram represents a distribution of float64 values. </p> +<pre data-language="go">type Float64Histogram struct { + // Counts contains the weights for each histogram bucket. + // + // Given N buckets, Count[n] is the weight of the range + // [bucket[n], bucket[n+1]), for 0 <= n < N. + Counts []uint64 + + // Buckets contains the boundaries of the histogram buckets, in increasing order. + // + // Buckets[0] is the inclusive lower bound of the minimum bucket while + // Buckets[len(Buckets)-1] is the exclusive upper bound of the maximum bucket. + // Hence, there are len(Buckets)-1 counts. Furthermore, len(Buckets) != 1, always, + // since at least two boundaries are required to describe one bucket (and 0 + // boundaries are used to describe 0 buckets). + // + // Buckets[0] is permitted to have value -Inf and Buckets[len(Buckets)-1] is + // permitted to have value Inf. + // + // For a given metric name, the value of Buckets is guaranteed not to change + // between calls until program exit. + // + // This slice value is permitted to alias with other Float64Histograms' Buckets + // fields, so the values within should only ever be read. If they need to be + // modified, the user must make a copy. + Buckets []float64 +} +</pre> <h2 id="Sample">type <span>Sample</span> <span title="Added in Go 1.16">1.16</span> </h2> <p>Sample captures a single metric sample. </p> +<pre data-language="go">type Sample struct { + // Name is the name of the metric sampled. + // + // It must correspond to a name in one of the metric descriptions + // returned by All. + Name string + + // Value is the value of the metric sample. + Value Value +} +</pre> <h2 id="Value">type <span>Value</span> <span title="Added in Go 1.16">1.16</span> </h2> <p>Value represents a metric value returned by the runtime. </p> +<pre data-language="go">type Value struct { + // contains filtered or unexported fields +} +</pre> <h3 id="Value.Float64">func (Value) <span>Float64</span> <span title="Added in Go 1.16">1.16</span> </h3> <pre data-language="go">func (v Value) Float64() float64</pre> <p>Float64 returns the internal float64 value for the metric. </p> +<p>If v.Kind() != KindFloat64, this method panics. </p> +<h3 id="Value.Float64Histogram">func (Value) <span>Float64Histogram</span> <span title="Added in Go 1.16">1.16</span> </h3> <pre data-language="go">func (v Value) Float64Histogram() *Float64Histogram</pre> <p>Float64Histogram returns the internal *Float64Histogram value for the metric. </p> +<p>If v.Kind() != KindFloat64Histogram, this method panics. </p> +<h3 id="Value.Kind">func (Value) <span>Kind</span> <span title="Added in Go 1.16">1.16</span> </h3> <pre data-language="go">func (v Value) Kind() ValueKind</pre> <p>Kind returns the tag representing the kind of value this is. </p> +<h3 id="Value.Uint64">func (Value) <span>Uint64</span> <span title="Added in Go 1.16">1.16</span> </h3> <pre data-language="go">func (v Value) Uint64() uint64</pre> <p>Uint64 returns the internal uint64 value for the metric. </p> +<p>If v.Kind() != KindUint64, this method panics. </p> +<h2 id="ValueKind">type <span>ValueKind</span> <span title="Added in Go 1.16">1.16</span> </h2> <p>ValueKind is a tag for a metric <a href="#Value">Value</a> which indicates its type. </p> +<pre data-language="go">type ValueKind int</pre> <pre data-language="go">const ( + // KindBad indicates that the Value has no type and should not be used. + KindBad ValueKind = iota + + // KindUint64 indicates that the type of the Value is a uint64. + KindUint64 + + // KindFloat64 indicates that the type of the Value is a float64. + KindFloat64 + + // KindFloat64Histogram indicates that the type of the Value is a *Float64Histogram. + KindFloat64Histogram +)</pre><div class="_attribution"> + <p class="_attribution-p"> + © Google, Inc.<br>Licensed under the Creative Commons Attribution License 3.0.<br> + <a href="http://golang.org/pkg/runtime/metrics/" class="_attribution-link">http://golang.org/pkg/runtime/metrics/</a> + </p> +</div> |