Performance measurement APIs
目录
- perf_hooks.performance
- performance.clearMarks([name])
- performance.clearMeasures([name])
- performance.clearResourceTimings([name])
- performance.eventLoopUtilization([utilization1[, utilization2]])
- performance.getEntries()
- performance.getEntriesByName(name[, type])
- performance.getEntriesByType(type)
- performance.mark([name[, options]])
- performance.markResourceTiming(timingInfo, requestedUrl, initiatorType, global, cacheMode)
- performance.measure(name[, startMarkOrOptions[, endMark]])
- performance.nodeTiming
- performance.now()
- performance.timeOrigin
- performance.timerify(fn[, options])
- performance.toJSON()
- Class: PerformanceEntry
- performanceEntry.detail
- performanceEntry.duration
- performanceEntry.entryType
- performanceEntry.flags
- performanceEntry.name
- performanceEntry.kind
- performanceEntry.startTime
- Garbage Collection ('gc') Details
- HTTP ('http') Details
- HTTP/2 ('http2') Details
- Timerify ('function') Details
- Net ('net') Details
- DNS ('dns') Details
- Class: PerformanceNodeTiming
- Class: PerformanceResourceTiming
- performanceResourceTiming.workerStart
- performanceResourceTiming.redirectStart
- performanceResourceTiming.redirectEnd
- performanceResourceTiming.fetchStart
- performanceResourceTiming.domainLookupStart
- performanceResourceTiming.domainLookupEnd
- performanceResourceTiming.connectStart
- performanceResourceTiming.connectEnd
- performanceResourceTiming.secureConnectionStart
- performanceResourceTiming.requestStart
- performanceResourceTiming.responseEnd
- performanceResourceTiming.transferSize
- performanceResourceTiming.encodedBodySize
- performanceResourceTiming.decodedBodySize
- performanceResourceTiming.toJSON()
- Class: perf_hooks.PerformanceObserver
- Class: PerformanceObserverEntryList
- perf_hooks.createHistogram([options])
- perf_hooks.monitorEventLoopDelay([options])
- Class: Histogram
- histogram.count
- histogram.countBigInt
- histogram.exceeds
- histogram.exceedsBigInt
- histogram.max
- histogram.maxBigInt
- histogram.mean
- histogram.min
- histogram.minBigInt
- histogram.percentile(percentile)
- histogram.percentileBigInt(percentile)
- histogram.percentiles
- histogram.percentilesBigInt
- histogram.reset()
- histogram.stddev
- Class: IntervalHistogram extends Histogram
- Class: RecordableHistogram extends Histogram
- Examples
自 v8.5.0 版本开始新增
源代码: lib/perf_hooks.js
This module provides an implementation of a subset of the W3C Web Performance APIs as well as additional APIs for Node.js-specific performance measurements.
Node.js supports the following Web Performance APIs:
JS
M perf_hooks.performance
自 v8.5.0 版本开始新增
An object that can be used to collect performance metrics from the current
Node.js instance. It is similar to window.performance
in browsers.
M performance.clearMarks([name])
自 v8.5.0 版本开始新增
name
string
If name
is not provided, removes all PerformanceMark
objects from the
Performance Timeline. If name
is provided, removes only the named mark.
M performance.clearMeasures([name])
自 v16.7.0 版本开始新增
name
string
If name
is not provided, removes all PerformanceMeasure
objects from the
Performance Timeline. If name
is provided, removes only the named measure.
M performance.clearResourceTimings([name])
自 v16.17.0 版本开始新增
name
string
If name
is not provided, removes all PerformanceResourceTiming
objects from
the Resource Timeline. If name
is provided, removes only the named resource.
M performance.eventLoopUtilization([utilization1[, utilization2]])
自 v14.10.0, v12.19.0 版本开始新增
utilization1
Object
The result of a previous call toeventLoopUtilization()
.utilization2
Object
The result of a previous call toeventLoopUtilization()
prior toutilization1
.- Returns
Object
The eventLoopUtilization()
method returns an object that contains the
cumulative duration of time the event loop has been both idle and active as a
high resolution milliseconds timer. The utilization
value is the calculated
Event Loop Utilization (ELU).
If bootstrapping has not yet finished on the main thread the properties have
the value of 0
. The ELU is immediately available on Worker threads since
bootstrap happens within the event loop.
Both utilization1
and utilization2
are optional parameters.
If utilization1
is passed, then the delta between the current call's active
and idle
times, as well as the corresponding utilization
value are
calculated and returned (similar to process.hrtime()
).
If utilization1
and utilization2
are both passed, then the delta is
calculated between the two arguments. This is a convenience option because,
unlike process.hrtime()
, calculating the ELU is more complex than a
single subtraction.
ELU is similar to CPU utilization, except that it only measures event loop
statistics and not CPU usage. It represents the percentage of time the event
loop has spent outside the event loop's event provider (e.g. epoll_wait
).
No other CPU idle time is taken into consideration. The following is an example
of how a mostly idle process will have a high ELU.
JS
Although the CPU is mostly idle while running this script, the value of
utilization
is 1
. This is because the call to
child_process.spawnSync()
blocks the event loop from proceeding.
Passing in a user-defined object instead of the result of a previous call to
eventLoopUtilization()
will lead to undefined behavior. The return values
are not guaranteed to reflect any correct state of the event loop.
M performance.getEntries()
自 v16.7.0 版本开始新增
- Returns: PerformanceEntry[]
Returns a list of PerformanceEntry
objects in chronological order with
respect to performanceEntry.startTime
. If you are only interested in
performance entries of certain types or that have certain names, see
performance.getEntriesByType()
and performance.getEntriesByName()
.
M performance.getEntriesByName(name[, type])
自 v16.7.0 版本开始新增
Returns a list of PerformanceEntry
objects in chronological order
with respect to performanceEntry.startTime
whose performanceEntry.name
is
equal to name
, and optionally, whose performanceEntry.entryType
is equal to
type
.
M performance.getEntriesByType(type)
自 v16.7.0 版本开始新增
type
string
- Returns: PerformanceEntry[]
Returns a list of PerformanceEntry
objects in chronological order
with respect to performanceEntry.startTime
whose performanceEntry.entryType
is equal to type
.
M performance.mark([name[, options]])
历史
版本 | 历史变更 |
---|---|
v16.0.0 | Updated to conform to the User Timing Level 3 specification. |
v8.5.0 | 自 v8.5.0 版本开始新增 |
Creates a new PerformanceMark
entry in the Performance Timeline. A
PerformanceMark
is a subclass of PerformanceEntry
whose
performanceEntry.entryType
is always 'mark'
, and whose
performanceEntry.duration
is always 0
. Performance marks are used
to mark specific significant moments in the Performance Timeline.
The created PerformanceMark
entry is put in the global Performance Timeline
and can be queried with performance.getEntries
,
performance.getEntriesByName
, and performance.getEntriesByType
. When the
observation is performed, the entries should be cleared from the global
Performance Timeline manually with performance.clearMarks
.
M performance.markResourceTiming(timingInfo, requestedUrl, initiatorType, global, cacheMode)
自 v16.17.0 版本开始新增
timingInfo
Object
Fetch Timing InforequestedUrl
string
The resource urlinitiatorType
string
The initiator name, e.g: 'fetch'global
Object
cacheMode
string
The cache mode must be an empty string ('') or 'local'
This property is an extension by Node.js. It is not available in Web browsers.
Creates a new PerformanceResourceTiming
entry in the Resource Timeline. A
PerformanceResourceTiming
is a subclass of PerformanceEntry
whose
performanceEntry.entryType
is always 'resource'
. Performance resources
are used to mark moments in the Resource Timeline.
The created PerformanceMark
entry is put in the global Resource Timeline
and can be queried with performance.getEntries
,
performance.getEntriesByName
, and performance.getEntriesByType
. When the
observation is performed, the entries should be cleared from the global
Performance Timeline manually with performance.clearResourceTimings
.
M performance.measure(name[, startMarkOrOptions[, endMark]])
历史
版本 | 历史变更 |
---|---|
v16.0.0 | Updated to conform to the User Timing Level 3 specification. |
v13.13.0, v12.16.3 | Make `startMark` and `endMark` parameters optional. |
v8.5.0 | 自 v8.5.0 版本开始新增 |
name
string
startMarkOrOptions
string
|Object
Optional.detail
any
Additional optional detail to include with the measure.duration
number
Duration between start and end times.end
number
|string
Timestamp to be used as the end time, or a string identifying a previously recorded mark.start
number
|string
Timestamp to be used as the start time, or a string identifying a previously recorded mark.
endMark
string
Optional. Must be omitted ifstartMarkOrOptions
is anObject
.
Creates a new PerformanceMeasure
entry in the Performance Timeline. A
PerformanceMeasure
is a subclass of PerformanceEntry
whose
performanceEntry.entryType
is always 'measure'
, and whose
performanceEntry.duration
measures the number of milliseconds elapsed since
startMark
and endMark
.
The startMark
argument may identify any existing PerformanceMark
in the
Performance Timeline, or may identify any of the timestamp properties
provided by the PerformanceNodeTiming
class. If the named startMark
does
not exist, an error is thrown.
The optional endMark
argument must identify any existing PerformanceMark
in the Performance Timeline or any of the timestamp properties provided by the
PerformanceNodeTiming
class. endMark
will be performance.now()
if no parameter is passed, otherwise if the named endMark
does not exist, an
error will be thrown.
The created PerformanceMeasure
entry is put in the global Performance Timeline
and can be queried with performance.getEntries
,
performance.getEntriesByName
, and performance.getEntriesByType
. When the
observation is performed, the entries should be cleared from the global
Performance Timeline manually with performance.clearMeasures
.
M performance.nodeTiming
自 v8.5.0 版本开始新增
This property is an extension by Node.js. It is not available in Web browsers.
An instance of the PerformanceNodeTiming
class that provides performance
metrics for specific Node.js operational milestones.
M performance.now()
自 v8.5.0 版本开始新增
- Returns:
number
Returns the current high resolution millisecond timestamp, where 0 represents
the start of the current node
process.
M performance.timeOrigin
自 v8.5.0 版本开始新增
The timeOrigin
specifies the high resolution millisecond timestamp at
which the current node
process began, measured in Unix time.
M performance.timerify(fn[, options])
历史
版本 | 历史变更 |
---|---|
v16.0.0 | Added the histogram option. |
v16.0.0 | Re-implemented to use pure-JavaScript and the ability to time async functions. |
v8.5.0 | 自 v8.5.0 版本开始新增 |
fn
Function
options
Object
histogram
RecordableHistogram
A histogram object created usingperf_hooks.createHistogram()
that will record runtime durations in nanoseconds.
This property is an extension by Node.js. It is not available in Web browsers.
Wraps a function within a new function that measures the running time of the
wrapped function. A PerformanceObserver
must be subscribed to the 'function'
event type in order for the timing details to be accessed.
JS
If the wrapped function returns a promise, a finally handler will be attached to the promise and the duration will be reported once the finally handler is invoked.
M performance.toJSON()
自 v16.1.0 版本开始新增
An object which is JSON representation of the performance
object. It
is similar to window.performance.toJSON
in browsers.
C PerformanceEntry
自 v8.5.0 版本开始新增
M performanceEntry.detail
自 v16.0.0 版本开始新增
Additional detail specific to the entryType
.
M performanceEntry.duration
自 v8.5.0 版本开始新增
The total number of milliseconds elapsed for this entry. This value will not be meaningful for all Performance Entry types.
M performanceEntry.entryType
自 v8.5.0 版本开始新增
The type of the performance entry. It may be one of:
'node'
(Node.js only)'mark'
(available on the Web)'measure'
(available on the Web)'gc'
(Node.js only)'function'
(Node.js only)'http2'
(Node.js only)'http'
(Node.js only)
M performanceEntry.flags
历史
版本 | 历史变更 |
---|---|
v16.0.0 | Runtime deprecated. Now moved to the detail property when entryType is 'gc'. |
v13.9.0, v12.17.0 | 自 v13.9.0, v12.17.0 版本开始新增 |
This property is an extension by Node.js. It is not available in Web browsers.
When performanceEntry.entryType
is equal to 'gc'
, the performance.flags
property contains additional information about garbage collection operation.
The value may be one of:
perf_hooks.constants.NODE_PERFORMANCE_GC_FLAGS_NO
perf_hooks.constants.NODE_PERFORMANCE_GC_FLAGS_CONSTRUCT_RETAINED
perf_hooks.constants.NODE_PERFORMANCE_GC_FLAGS_FORCED
perf_hooks.constants.NODE_PERFORMANCE_GC_FLAGS_SYNCHRONOUS_PHANTOM_PROCESSING
perf_hooks.constants.NODE_PERFORMANCE_GC_FLAGS_ALL_AVAILABLE_GARBAGE
perf_hooks.constants.NODE_PERFORMANCE_GC_FLAGS_ALL_EXTERNAL_MEMORY
perf_hooks.constants.NODE_PERFORMANCE_GC_FLAGS_SCHEDULE_IDLE
M performanceEntry.name
自 v8.5.0 版本开始新增
The name of the performance entry.
M performanceEntry.kind
历史
版本 | 历史变更 |
---|---|
v16.0.0 | Runtime deprecated. Now moved to the detail property when entryType is 'gc'. |
v8.5.0 | 自 v8.5.0 版本开始新增 |
This property is an extension by Node.js. It is not available in Web browsers.
When performanceEntry.entryType
is equal to 'gc'
, the performance.kind
property identifies the type of garbage collection operation that occurred.
The value may be one of:
perf_hooks.constants.NODE_PERFORMANCE_GC_MAJOR
perf_hooks.constants.NODE_PERFORMANCE_GC_MINOR
perf_hooks.constants.NODE_PERFORMANCE_GC_INCREMENTAL
perf_hooks.constants.NODE_PERFORMANCE_GC_WEAKCB
M performanceEntry.startTime
自 v8.5.0 版本开始新增
The high resolution millisecond timestamp marking the starting time of the Performance Entry.
Garbage Collection ('gc') Details
When performanceEntry.type
is equal to 'gc'
, the performanceEntry.detail
property will be an Object
with two properties:
kind
number
One of:perf_hooks.constants.NODE_PERFORMANCE_GC_MAJOR
perf_hooks.constants.NODE_PERFORMANCE_GC_MINOR
perf_hooks.constants.NODE_PERFORMANCE_GC_INCREMENTAL
perf_hooks.constants.NODE_PERFORMANCE_GC_WEAKCB
flags
number
One of:perf_hooks.constants.NODE_PERFORMANCE_GC_FLAGS_NO
perf_hooks.constants.NODE_PERFORMANCE_GC_FLAGS_CONSTRUCT_RETAINED
perf_hooks.constants.NODE_PERFORMANCE_GC_FLAGS_FORCED
perf_hooks.constants.NODE_PERFORMANCE_GC_FLAGS_SYNCHRONOUS_PHANTOM_PROCESSING
perf_hooks.constants.NODE_PERFORMANCE_GC_FLAGS_ALL_AVAILABLE_GARBAGE
perf_hooks.constants.NODE_PERFORMANCE_GC_FLAGS_ALL_EXTERNAL_MEMORY
perf_hooks.constants.NODE_PERFORMANCE_GC_FLAGS_SCHEDULE_IDLE
HTTP ('http') Details
When performanceEntry.type
is equal to 'http'
, the performanceEntry.detail
property will be an Object
containing additional information.
If performanceEntry.name
is equal to HttpClient
, the detail
will contain the following properties: req
, res
. And the req
property
will be an Object
containing method
, url
, headers
, the res
property
will be an Object
containing statusCode
, statusMessage
, headers
.
If performanceEntry.name
is equal to HttpRequest
, the detail
will contain the following properties: req
, res
. And the req
property
will be an Object
containing method
, url
, headers
, the res
property
will be an Object
containing statusCode
, statusMessage
, headers
.
This could add additional memory overhead and should only be used for diagnostic purposes, not left turned on in production by default.
HTTP/2 ('http2') Details
When performanceEntry.type
is equal to 'http2'
, the
performanceEntry.detail
property will be an Object
containing
additional performance information.
If performanceEntry.name
is equal to Http2Stream
, the detail
will contain the following properties:
bytesRead
number
The number ofDATA
frame bytes received for thisHttp2Stream
.bytesWritten
number
The number ofDATA
frame bytes sent for thisHttp2Stream
.id
number
The identifier of the associatedHttp2Stream
timeToFirstByte
number
The number of milliseconds elapsed between thePerformanceEntry
startTime
and the reception of the firstDATA
frame.timeToFirstByteSent
number
The number of milliseconds elapsed between thePerformanceEntry
startTime
and sending of the firstDATA
frame.timeToFirstHeader
number
The number of milliseconds elapsed between thePerformanceEntry
startTime
and the reception of the first header.
If performanceEntry.name
is equal to Http2Session
, the detail
will
contain the following properties:
bytesRead
number
The number of bytes received for thisHttp2Session
.bytesWritten
number
The number of bytes sent for thisHttp2Session
.framesReceived
number
The number of HTTP/2 frames received by theHttp2Session
.framesSent
number
The number of HTTP/2 frames sent by theHttp2Session
.maxConcurrentStreams
number
The maximum number of streams concurrently open during the lifetime of theHttp2Session
.pingRTT
number
The number of milliseconds elapsed since the transmission of aPING
frame and the reception of its acknowledgment. Only present if aPING
frame has been sent on theHttp2Session
.streamAverageDuration
number
The average duration (in milliseconds) for allHttp2Stream
instances.streamCount
number
The number ofHttp2Stream
instances processed by theHttp2Session
.type
string
Either'server'
or'client'
to identify the type ofHttp2Session
.
Timerify ('function') Details
When performanceEntry.type
is equal to 'function'
, the
performanceEntry.detail
property will be an Array
listing
the input arguments to the timed function.
Net ('net') Details
When performanceEntry.type
is equal to 'net'
, the
performanceEntry.detail
property will be an Object
containing
additional information.
If performanceEntry.name
is equal to connect
, the detail
will contain the following properties: host
, port
.
DNS ('dns') Details
When performanceEntry.type
is equal to 'dns'
, the
performanceEntry.detail
property will be an Object
containing
additional information.
If performanceEntry.name
is equal to lookup
, the detail
will contain the following properties: hostname
, family
, hints
, verbatim
,
addresses
.
If performanceEntry.name
is equal to lookupService
, the detail
will
contain the following properties: host
, port
, hostname
, service
.
If performanceEntry.name
is equal to queryxxx
or getHostByAddr
, the detail
will
contain the following properties: host
, ttl
, result
. The value of result
is
same as the result of queryxxx
or getHostByAddr
.
C PerformanceNodeTiming
自 v8.5.0 版本开始新增
- Extends:
PerformanceEntry
This property is an extension by Node.js. It is not available in Web browsers.
Provides timing details for Node.js itself. The constructor of this class is not exposed to users.
M performanceNodeTiming.bootstrapComplete
自 v8.5.0 版本开始新增
The high resolution millisecond timestamp at which the Node.js process completed bootstrapping. If bootstrapping has not yet finished, the property has the value of -1.
M performanceNodeTiming.environment
自 v8.5.0 版本开始新增
The high resolution millisecond timestamp at which the Node.js environment was initialized.
M performanceNodeTiming.idleTime
自 v14.10.0, v12.19.0 版本开始新增
The high resolution millisecond timestamp of the amount of time the event loop
has been idle within the event loop's event provider (e.g. epoll_wait
). This
does not take CPU usage into consideration. If the event loop has not yet
started (e.g., in the first tick of the main script), the property has the
value of 0.
M performanceNodeTiming.loopExit
自 v8.5.0 版本开始新增
The high resolution millisecond timestamp at which the Node.js event loop
exited. If the event loop has not yet exited, the property has the value of -1.
It can only have a value of not -1 in a handler of the 'exit'
event.
M performanceNodeTiming.loopStart
自 v8.5.0 版本开始新增
The high resolution millisecond timestamp at which the Node.js event loop started. If the event loop has not yet started (e.g., in the first tick of the main script), the property has the value of -1.
M performanceNodeTiming.nodeStart
自 v8.5.0 版本开始新增
The high resolution millisecond timestamp at which the Node.js process was initialized.
M performanceNodeTiming.v8Start
自 v8.5.0 版本开始新增
The high resolution millisecond timestamp at which the V8 platform was initialized.
C PerformanceResourceTiming
自 v16.17.0 版本开始新增
- Extends:
PerformanceEntry
Provides detailed network timing data regarding the loading of an application's resources.
The constructor of this class is not exposed to users directly.
M performanceResourceTiming.workerStart
自 v16.17.0 版本开始新增
The high resolution millisecond timestamp at immediately before dispatching
the fetch
request. If the resource is not intercepted by a worker the property
will always return 0.
M performanceResourceTiming.redirectStart
自 v16.17.0 版本开始新增
The high resolution millisecond timestamp that represents the start time of the fetch which initiates the redirect.
M performanceResourceTiming.redirectEnd
自 v16.17.0 版本开始新增
The high resolution millisecond timestamp that will be created immediately after receiving the last byte of the response of the last redirect.
M performanceResourceTiming.fetchStart
自 v16.17.0 版本开始新增
The high resolution millisecond timestamp immediately before the Node.js starts to fetch the resource.
M performanceResourceTiming.domainLookupStart
自 v16.17.0 版本开始新增
The high resolution millisecond timestamp immediately before the Node.js starts the domain name lookup for the resource.
M performanceResourceTiming.domainLookupEnd
自 v16.17.0 版本开始新增
The high resolution millisecond timestamp representing the time immediately after the Node.js finished the domain name lookup for the resource.
M performanceResourceTiming.connectStart
自 v16.17.0 版本开始新增
The high resolution millisecond timestamp representing the time immediately before Node.js starts to establish the connection to the server to retrieve the resource.
M performanceResourceTiming.connectEnd
自 v16.17.0 版本开始新增
The high resolution millisecond timestamp representing the time immediately after Node.js finishes establishing the connection to the server to retrieve the resource.
M performanceResourceTiming.secureConnectionStart
自 v16.17.0 版本开始新增
The high resolution millisecond timestamp representing the time immediately before Node.js starts the handshake process to secure the current connection.
M performanceResourceTiming.requestStart
自 v16.17.0 版本开始新增
The high resolution millisecond timestamp representing the time immediately before Node.js receives the first byte of the response from the server.
M performanceResourceTiming.responseEnd
自 v16.17.0 版本开始新增
The high resolution millisecond timestamp representing the time immediately after Node.js receives the last byte of the resource or immediately before the transport connection is closed, whichever comes first.
M performanceResourceTiming.transferSize
自 v16.17.0 版本开始新增
A number representing the size (in octets) of the fetched resource. The size includes the response header fields plus the response payload body.
M performanceResourceTiming.encodedBodySize
自 v16.17.0 版本开始新增
A number representing the size (in octets) received from the fetch (HTTP or cache), of the payload body, before removing any applied content-codings.
M performanceResourceTiming.decodedBodySize
自 v16.17.0 版本开始新增
A number representing the size (in octets) received from the fetch (HTTP or cache), of the message body, after removing any applied content-codings.
M performanceResourceTiming.toJSON()
自 v16.17.0 版本开始新增
Returns a object
that is the JSON representation of the
PerformanceResourceTiming
object
C perf_hooks.PerformanceObserver
M new PerformanceObserver(callback)
自 v8.5.0 版本开始新增
callback
Function
list
PerformanceObserverEntryList
observer
PerformanceObserver
PerformanceObserver
objects provide notifications when new
PerformanceEntry
instances have been added to the Performance Timeline.
JS
Because PerformanceObserver
instances introduce their own additional
performance overhead, instances should not be left subscribed to notifications
indefinitely. Users should disconnect observers as soon as they are no
longer needed.
The callback
is invoked when a PerformanceObserver
is
notified about new PerformanceEntry
instances. The callback receives a
PerformanceObserverEntryList
instance and a reference to the
PerformanceObserver
.
M performanceObserver.disconnect()
自 v8.5.0 版本开始新增
Disconnects the PerformanceObserver
instance from all notifications.
M performanceObserver.observe(options)
历史
版本 | 历史变更 |
---|---|
v16.7.0 | Updated to conform to Performance Timeline Level 2. The buffered option has been added back. |
v16.0.0 | Updated to conform to User Timing Level 3. The buffered option has been removed. |
v8.5.0 | 自 v8.5.0 版本开始新增 |
options
Object
type
string
A singlePerformanceEntry
type. Must not be given ifentryTypes
is already specified.entryTypes
string[] An array of strings identifying the types ofPerformanceEntry
instances the observer is interested in. If not provided an error will be thrown.buffered
boolean
If true, the observer callback is called with a list globalPerformanceEntry
buffered entries. If false, onlyPerformanceEntry
s created after the time point are sent to the observer callback. Default:false
.
Subscribes the PerformanceObserver
instance to notifications of new
PerformanceEntry
instances identified either by options.entryTypes
or options.type
:
JS
C PerformanceObserverEntryList
自 v8.5.0 版本开始新增
The PerformanceObserverEntryList
class is used to provide access to the
PerformanceEntry
instances passed to a PerformanceObserver
.
The constructor of this class is not exposed to users.
M performanceObserverEntryList.getEntries()
自 v8.5.0 版本开始新增
- Returns: PerformanceEntry[]
Returns a list of PerformanceEntry
objects in chronological order
with respect to performanceEntry.startTime
.
JS
M performanceObserverEntryList.getEntriesByName(name[, type])
自 v8.5.0 版本开始新增
Returns a list of PerformanceEntry
objects in chronological order
with respect to performanceEntry.startTime
whose performanceEntry.name
is
equal to name
, and optionally, whose performanceEntry.entryType
is equal to
type
.
JS
M performanceObserverEntryList.getEntriesByType(type)
自 v8.5.0 版本开始新增
type
string
- Returns: PerformanceEntry[]
Returns a list of PerformanceEntry
objects in chronological order
with respect to performanceEntry.startTime
whose performanceEntry.entryType
is equal to type
.
JS
M perf_hooks.createHistogram([options])
自 v15.9.0 版本开始新增
options
Object
lowest
number
|bigint
The lowest discernible value. Must be an integer value greater than 0. Default:1
.highest
number
|bigint
The highest recordable value. Must be an integer value that is equal to or greater than two timeslowest
. Default:Number.MAX_SAFE_INTEGER
.figures
number
The number of accuracy digits. Must be a number between1
and5
. Default:3
.
- Returns
RecordableHistogram
Returns a RecordableHistogram
.
M perf_hooks.monitorEventLoopDelay([options])
自 v11.10.0 版本开始新增
options
Object
resolution
number
The sampling rate in milliseconds. Must be greater than zero. Default:10
.
- Returns:
IntervalHistogram
This property is an extension by Node.js. It is not available in Web browsers.
Creates an IntervalHistogram
object that samples and reports the event loop
delay over time. The delays will be reported in nanoseconds.
Using a timer to detect approximate event loop delay works because the execution of timers is tied specifically to the lifecycle of the libuv event loop. That is, a delay in the loop will cause a delay in the execution of the timer, and those delays are specifically what this API is intended to detect.
JS
C Histogram
自 v11.10.0 版本开始新增
M histogram.count
自 v16.14.0 版本开始新增
The number of samples recorded by the histogram.
M histogram.countBigInt
自 v16.14.0 版本开始新增
The number of samples recorded by the histogram.
M histogram.exceeds
自 v11.10.0 版本开始新增
The number of times the event loop delay exceeded the maximum 1 hour event loop delay threshold.
M histogram.exceedsBigInt
自 v16.14.0 版本开始新增
The number of times the event loop delay exceeded the maximum 1 hour event loop delay threshold.
M histogram.max
自 v11.10.0 版本开始新增
The maximum recorded event loop delay.
M histogram.maxBigInt
自 v16.14.0 版本开始新增
The maximum recorded event loop delay.
M histogram.mean
自 v11.10.0 版本开始新增
The mean of the recorded event loop delays.
M histogram.min
自 v11.10.0 版本开始新增
The minimum recorded event loop delay.
M histogram.minBigInt
自 v16.14.0 版本开始新增
The minimum recorded event loop delay.
M histogram.percentile(percentile)
自 v11.10.0 版本开始新增
Returns the value at the given percentile.
M histogram.percentileBigInt(percentile)
自 v16.14.0 版本开始新增
Returns the value at the given percentile.
M histogram.percentiles
自 v11.10.0 版本开始新增
Returns a Map
object detailing the accumulated percentile distribution.
M histogram.percentilesBigInt
自 v16.14.0 版本开始新增
Returns a Map
object detailing the accumulated percentile distribution.
M histogram.reset()
自 v11.10.0 版本开始新增
Resets the collected histogram data.
M histogram.stddev
自 v11.10.0 版本开始新增
The standard deviation of the recorded event loop delays.
C IntervalHistogram extends Histogram
A Histogram
that is periodically updated on a given interval.
M histogram.disable()
自 v11.10.0 版本开始新增
- Returns:
boolean
Disables the update interval timer. Returns true
if the timer was
stopped, false
if it was already stopped.
M histogram.enable()
自 v11.10.0 版本开始新增
- Returns:
boolean
Enables the update interval timer. Returns true
if the timer was
started, false
if it was already started.
Cloning an IntervalHistogram
IntervalHistogram
instances can be cloned via MessagePort
. On the receiving
end, the histogram is cloned as a plain Histogram
object that does not
implement the enable()
and disable()
methods.
C RecordableHistogram extends Histogram
自 v15.9.0 版本开始新增
M histogram.add(other)
自 v16.14.0 版本开始新增
other
RecordableHistogram
Adds the values from other
to this histogram.
M histogram.record(val)
自 v15.9.0 版本开始新增
M histogram.recordDelta()
自 v15.9.0 版本开始新增
Calculates the amount of time (in nanoseconds) that has passed since the
previous call to recordDelta()
and records that amount in the histogram.
Examples
Measuring the duration of async operations
The following example uses the Async Hooks and Performance APIs to measure the actual duration of a Timeout operation (including the amount of time it took to execute the callback).
JS
Measuring how long it takes to load dependencies
The following example measures the duration of require()
operations to load
dependencies:
JS
Measuring how long one HTTP round-trip takes
The following example is used to trace the time spent by HTTP client
(OutgoingMessage
) and HTTP request (IncomingMessage
). For HTTP client,
it means the time interval between starting the request and receiving the
response, and for HTTP request, it means the time interval between receiving
the request and sending the response:
JS
Measuring how long the net.connect
(only for TCP) takes when the connection is successful
JS
Measuring how long the DNS takes when the request is successful
JS