Chrome DevTools Protocol

Methods

Tracing.end

Stop trace events collection.

Tracing.start

Start trace events collection.

parameters
categories
string

Category/tag filter

ExperimentalDeprecated
options
string

Tracing options

ExperimentalDeprecated
bufferUsageReportingInterval
number

If set, the agent will issue bufferUsage events at this interval, specified in milliseconds

Experimental
transferMode
string

Whether to report trace events as series of dataCollected events or to save trace to a stream (defaults to ReportEvents).

Allowed Values: ReportEvents, ReturnAsStream
streamFormat
StreamFormat

Trace data format to use. This only applies when using ReturnAsStream transfer mode (defaults to json).

streamCompression
StreamCompression

Compression format to use. This only applies when using ReturnAsStream transfer mode (defaults to none)

Experimental
traceConfig
TraceConfig
perfettoConfig
string

Base64-encoded serialized perfetto.protos.TraceConfig protobuf message When specified, the parameters categories, options, traceConfig are ignored. (Encoded as a base64 string when passed over JSON)

Experimental
tracingBackend
TracingBackend

Backend type (defaults to auto)

Experimental

Tracing.getCategories Experimental

Gets supported tracing categories.

Return Object
categories
array[ string ]

A list of supported tracing categories.

Tracing.recordClockSyncMarker Experimental

Record a clock sync marker in the trace.

parameters
syncId
string

The ID of this clock sync marker

Tracing.requestMemoryDump Experimental

Request a global memory dump.

parameters
deterministic
boolean

Enables more deterministic results by forcing garbage collection

levelOfDetail
MemoryDumpLevelOfDetail

Specifies level of details in memory dump. Defaults to "detailed".

Return Object
dumpGuid
string

GUID of the resulting global memory dump.

success
boolean

True iff the global memory dump succeeded.

Events

Tracing.tracingComplete

Signals that tracing is stopped and there is no trace buffers pending flush, all data were delivered via dataCollected events.

parameters
dataLossOccurred
boolean

Indicates whether some trace data is known to have been lost, e.g. because the trace ring buffer wrapped around.

stream
IO.StreamHandle

A handle of the stream that holds resulting trace data.

traceFormat
StreamFormat

Trace data format of returned stream.

streamCompression
StreamCompression

Compression format of returned stream.

Tracing.bufferUsage Experimental

parameters
percentFull
number

A number in range [0..1] that indicates the used size of event buffer as a fraction of its total size.

eventCount
number

An approximate number of events in the trace log.

value
number

A number in range [0..1] that indicates the used size of event buffer as a fraction of its total size.

Tracing.dataCollected Experimental

Contains a bucket of collected trace events. When tracing is stopped collected events will be sent as a sequence of dataCollected events followed by tracingComplete event.

parameters
value
array[ object ]

Types

Tracing.TraceConfig

Type: object

properties
recordMode
string

Controls how the trace buffer stores data. The default is recordUntilFull.

Allowed Values: recordUntilFull, recordContinuously, recordAsMuchAsPossible, echoToConsole
Experimental
traceBufferSizeInKb
number

Size of the trace buffer in kilobytes. If not specified or zero is passed, a default value of 200 MB would be used.

Experimental
enableSampling
boolean

Turns on JavaScript stack sampling.

Experimental
enableSystrace
boolean

Turns on system tracing.

Experimental
enableArgumentFilter
boolean

Turns on argument filter.

Experimental
includedCategories
array[ string ]

Included category filters.

excludedCategories
array[ string ]

Excluded category filters.

syntheticDelays
array[ string ]

Configuration to synthesize the delays in tracing.

Experimental
memoryDumpConfig
MemoryDumpConfig

Configuration for memory dump triggers. Used only when "memory-infra" category is enabled.

Experimental

Tracing.MemoryDumpConfig Experimental

Configuration for memory dump. Used only when "memory-infra" category is enabled.

Type: object

Tracing.MemoryDumpLevelOfDetail Experimental

Details exposed when memory request explicitly declared. Keep consistent with memory_dump_request_args.h and memory_instrumentation.mojom

Allowed Values: background, light, detailed

Type: string

Tracing.StreamCompression Experimental

Compression type to use for traces returned via streams.

Allowed Values: none, gzip

Type: string

Tracing.StreamFormat Experimental

Data format of a trace. Can be either the legacy JSON format or the protocol buffer format. Note that the JSON format will be deprecated soon.

Allowed Values: json, proto

Type: string

Tracing.TracingBackend Experimental

Backend type to use for tracing. chrome uses the Chrome-integrated tracing service and is supported on all platforms. system is only supported on Chrome OS and uses the Perfetto system tracing service. auto chooses system when the perfettoConfig provided to Tracing.start specifies at least one non-Chrome data source; otherwise uses chrome.

Allowed Values: auto, chrome, system

Type: string