View as markdown
Copy for LLM Open in ChatGPT Open in Claude Open in Perplexity

Tracing

Dependencies: IO

Commands

Tracing.end

Stop trace events collection.

Tracing.getCategories

Experimental

Gets supported tracing categories.

Return Object
Name Type Description
categories array<string> A list of supported tracing categories.

Tracing.getTrackEventDescriptor

Experimental

Return a descriptor for all available tracing categories.

Return Object
Name Type Description
descriptor binary Base64-encoded serialized perfetto.protos.TrackEventDescriptor protobuf message.

Tracing.recordClockSyncMarker

Experimental

Record a clock sync marker in the trace.

Parameters
Name Type Description
syncId string The ID of this clock sync marker

Tracing.requestMemoryDump

Experimental

Request a global memory dump.

Parameters
Name Type Description
deterministic (optional) boolean Enables more deterministic results by forcing garbage collection
levelOfDetail (optional) MemoryDumpLevelOfDetail Specifies level of details in memory dump. Defaults to "detailed".
Return Object
Name Type Description
dumpGuid string GUID of the resulting global memory dump.
success boolean True iff the global memory dump succeeded.

Tracing.start

Start trace events collection.

Parameters
Name Type Description
categories (optional) Experimental Deprecated string Category/tag filter
options (optional) Experimental Deprecated string Tracing options
bufferUsageReportingInterval (optional) Experimental number If set, the agent will issue bufferUsage events at this interval, specified in milliseconds
transferMode (optional) string Whether to report trace events as series of dataCollected events or to save trace to a
stream (defaults to `ReportEvents`).
streamFormat (optional) StreamFormat Trace data format to use. This only applies when using `ReturnAsStream`
transfer mode (defaults to `json`).
streamCompression (optional) Experimental StreamCompression Compression format to use. This only applies when using `ReturnAsStream`
transfer mode (defaults to `none`)
traceConfig (optional) TraceConfig
perfettoConfig (optional) Experimental binary Base64-encoded serialized perfetto.protos.TraceConfig protobuf message
When specified, the parameters `categories`, `options`, `traceConfig`
are ignored.
tracingBackend (optional) Experimental TracingBackend Backend type (defaults to `auto`)

Events

Tracing.bufferUsage

Experimental
Parameters
Name Type Description
percentFull (optional) number A number in range [0..1] that indicates the used size of event buffer as a fraction of its
total size.
eventCount (optional) number An approximate number of events in the trace log.
value (optional) 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
Name Type Description
value array<object>

Tracing.tracingComplete

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

Parameters
Name Type Description
dataLossOccurred boolean Indicates whether some trace data is known to have been lost, e.g. because the trace ring
buffer wrapped around.
stream (optional) IO.StreamHandle A handle of the stream that holds resulting trace data.
traceFormat (optional) StreamFormat Trace data format of returned stream.
streamCompression (optional) StreamCompression Compression format of returned stream.

Types

MemoryDumpConfig

(object) Experimental

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

TraceConfig

(object)
Properties
Name Type Description
recordMode (optional) Experimental string Controls how the trace buffer stores data. The default is `recordUntilFull`.
traceBufferSizeInKb (optional) Experimental number Size of the trace buffer in kilobytes. If not specified or zero is passed, a default value
of 200 MB would be used.
enableSampling (optional) Experimental boolean Turns on JavaScript stack sampling.
enableSystrace (optional) Experimental boolean Turns on system tracing.
enableArgumentFilter (optional) Experimental boolean Turns on argument filter.
includedCategories (optional) array<string> Included category filters.
excludedCategories (optional) array<string> Excluded category filters.
syntheticDelays (optional) Experimental array<string> Configuration to synthesize the delays in tracing.
memoryDumpConfig (optional) Experimental MemoryDumpConfig Configuration for memory dump triggers. Used only when "memory-infra" category is enabled.

StreamFormat

(string) 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

StreamCompression

(string) Experimental

Compression type to use for traces returned via streams.

Allowed Values
  • none
  • gzip

MemoryDumpLevelOfDetail

(string) 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

TracingBackend

(string) 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

Summary