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HeapProfiler

Experimental

Dependencies: Runtime

Commands

HeapProfiler.addInspectedHeapObject

Enables console to refer to the node with given id via $x (see Command Line API for more details
$x functions).

Parameters
Name Type Description
heapObjectId HeapSnapshotObjectId Heap snapshot object id to be accessible by means of $x command line API.

HeapProfiler.collectGarbage

HeapProfiler.disable

HeapProfiler.enable

HeapProfiler.getHeapObjectId

Parameters
Name Type Description
objectId Runtime.RemoteObjectId Identifier of the object to get heap object id for.
Return Object
Name Type Description
heapSnapshotObjectId HeapSnapshotObjectId Id of the heap snapshot object corresponding to the passed remote object id.

HeapProfiler.getObjectByHeapObjectId

Parameters
Name Type Description
objectId HeapSnapshotObjectId
objectGroup (optional) string Symbolic group name that can be used to release multiple objects.
Return Object
Name Type Description
result Runtime.RemoteObject Evaluation result.

HeapProfiler.getSamplingProfile

Return Object
Name Type Description
profile SamplingHeapProfile Return the sampling profile being collected.

HeapProfiler.startSampling

Parameters
Name Type Description
samplingInterval (optional) number Average sample interval in bytes. Poisson distribution is used for the intervals. The
default value is 32768 bytes.
stackDepth (optional) number Maximum stack depth. The default value is 128.
includeObjectsCollectedByMajorGC (optional) boolean By default, the sampling heap profiler reports only objects which are
still alive when the profile is returned via getSamplingProfile or
stopSampling, which is useful for determining what functions contribute
the most to steady-state memory usage. This flag instructs the sampling
heap profiler to also include information about objects discarded by
major GC, which will show which functions cause large temporary memory
usage or long GC pauses.
includeObjectsCollectedByMinorGC (optional) boolean By default, the sampling heap profiler reports only objects which are
still alive when the profile is returned via getSamplingProfile or
stopSampling, which is useful for determining what functions contribute
the most to steady-state memory usage. This flag instructs the sampling
heap profiler to also include information about objects discarded by
minor GC, which is useful when tuning a latency-sensitive application
for minimal GC activity.

HeapProfiler.startTrackingHeapObjects

Parameters
Name Type Description
trackAllocations (optional) boolean

HeapProfiler.stopSampling

Return Object
Name Type Description
profile SamplingHeapProfile Recorded sampling heap profile.

HeapProfiler.stopTrackingHeapObjects

Parameters
Name Type Description
reportProgress (optional) boolean If true 'reportHeapSnapshotProgress' events will be generated while snapshot is being taken
when the tracking is stopped.
treatGlobalObjectsAsRoots (optional) Deprecated boolean Deprecated in favor of `exposeInternals`.
captureNumericValue (optional) boolean If true, numerical values are included in the snapshot
exposeInternals (optional) Experimental boolean If true, exposes internals of the snapshot.

HeapProfiler.takeHeapSnapshot

Parameters
Name Type Description
reportProgress (optional) boolean If true 'reportHeapSnapshotProgress' events will be generated while snapshot is being taken.
treatGlobalObjectsAsRoots (optional) Deprecated boolean If true, a raw snapshot without artificial roots will be generated.
Deprecated in favor of `exposeInternals`.
captureNumericValue (optional) boolean If true, numerical values are included in the snapshot
exposeInternals (optional) Experimental boolean If true, exposes internals of the snapshot.

Events

HeapProfiler.addHeapSnapshotChunk

Parameters
Name Type Description
chunk string

HeapProfiler.heapStatsUpdate

If heap objects tracking has been started then backend may send update for one or more fragments

Parameters
Name Type Description
statsUpdate array<integer> An array of triplets. Each triplet describes a fragment. The first integer is the fragment
index, the second integer is a total count of objects for the fragment, the third integer is
a total size of the objects for the fragment.

HeapProfiler.lastSeenObjectId

If heap objects tracking has been started then backend regularly sends a current value for last
seen object id and corresponding timestamp. If the were changes in the heap since last event
then one or more heapStatsUpdate events will be sent before a new lastSeenObjectId event.

Parameters
Name Type Description
lastSeenObjectId integer
timestamp number

HeapProfiler.reportHeapSnapshotProgress

Parameters
Name Type Description
done integer
total integer
finished (optional) boolean

HeapProfiler.resetProfiles

Types

HeapSnapshotObjectId

(string)

Heap snapshot object id.

SamplingHeapProfileNode

(object)

Sampling Heap Profile node. Holds callsite information, allocation statistics and child nodes.

Properties
Name Type Description
callFrame Runtime.CallFrame Function location.
selfSize number Allocations size in bytes for the node excluding children.
id integer Node id. Ids are unique across all profiles collected between startSampling and stopSampling.
children array<SamplingHeapProfileNode> Child nodes.

SamplingHeapProfileSample

(object)

A single sample from a sampling profile.

Properties
Name Type Description
size number Allocation size in bytes attributed to the sample.
nodeId integer Id of the corresponding profile tree node.
ordinal number Time-ordered sample ordinal number. It is unique across all profiles retrieved
between startSampling and stopSampling.

SamplingHeapProfile

(object)

Sampling profile.

Properties
Name Type Description
head SamplingHeapProfileNode
samples array<SamplingHeapProfileSample>

Summary