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Standardize content-tracing

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Jessica Lord 2015-08-25 04:49:48 -07:00
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commit 703ced32db
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docs/api/content-tracing.md
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@ -1,9 +1,9 @@
# content-tracing # content-trace
The `content-trace` module is used to collect tracing data generated by the The `content-trace` module is used to collect tracing data generated by the
underlying Chromium content module. This module does not include a web interface underlying Chromium content module. This module does not include a web interface
so you need to open `chrome://tracing/` in a Chrome browser and load the generated so you need to open `chrome://tracing/` in a Chrome browser and load the
file to view the result. generated file to view the result.
```javascript ```javascript
var tracing = require('content-tracing'); var tracing = require('content-tracing');
@ -18,17 +18,20 @@ tracing.startRecording('*', tracing.DEFAULT_OPTIONS, function() {
}); });
``` ```
## tracing.getCategories(callback) ## Methods
- The `content-trace` module has the following methods:
### `tracing.getCategories(callback)`
* `callback` Function * `callback` Function
Get a set of category groups. The category groups can change as new code paths Get a set of category groups. The category groups can change as new code paths
are reached. are reached.
Once all child processes have acked to the `getCategories` request, `callback` Once all child processes have acked to the `getCategories` request, `callback` is invoked with an array of category groups.
is invoked with an array of category groups.
## tracing.startRecording(categoryFilter, traceOptions, callback) ### `tracing.startRecording(categoryFilter, traceOptions, callback)`
* `categoryFilter` String * `categoryFilter` String
* `traceOptions` String * `traceOptions` String
@ -36,9 +39,9 @@ is invoked with an array of category groups.
Start recording on all processes. Start recording on all processes.
Recording begins immediately locally, and asynchronously on child processes Recording begins immediately locally and asynchronously on child processes
as soon as they receive the EnableRecording request. Once all child processes as soon as they receive the EnableRecording request. Once all child processes
have acked to the `startRecording` request, `callback` will be called back. have acked to the `startRecording` request the `callback` will be called.
`categoryFilter` is a filter to control what category groups should be `categoryFilter` is a filter to control what category groups should be
traced. A filter can have an optional `-` prefix to exclude category groups traced. A filter can have an optional `-` prefix to exclude category groups
@ -51,8 +54,8 @@ Examples:
* `test_MyTest*,test_OtherStuff`, * `test_MyTest*,test_OtherStuff`,
* `"-excluded_category1,-excluded_category2` * `"-excluded_category1,-excluded_category2`
`traceOptions` controls what kind of tracing is enabled, it is a comma-delimited list. `traceOptions` controls what kind of tracing is enabled, it is a comma-delimited
Possible options are: list. Possible options are:
* `record-until-full` * `record-until-full`
* `record-continuously` * `record-continuously`
@ -66,10 +69,10 @@ the last one takes precedence. If none of the trace recording mode is specified,
recording mode is `record-until-full`. recording mode is `record-until-full`.
The trace option will first be reset to the default option (record_mode set to The trace option will first be reset to the default option (record_mode set to
`record-until-full`, enable_sampling and enable_systrace set to false) `record-until-full`, enable_sampling and enable_systrace set to `false`)
before options parsed from `traceOptions` are applied on it. before options parsed from `traceOptions` are applied on it.
## tracing.stopRecording(resultFilePath, callback) ### `tracing.stopRecording(resultFilePath, callback)`
* `resultFilePath` String * `resultFilePath` String
* `callback` Function * `callback` Function
@ -78,18 +81,17 @@ Stop recording on all processes.
Child processes typically are caching trace data and only rarely flush and send Child processes typically are caching trace data and only rarely flush and send
trace data back to the main process. That is because it may be an expensive trace data back to the main process. That is because it may be an expensive
operation to send the trace data over IPC, and we would like to avoid much operation to send the trace data over IPC, and we would like to avoid runtime overhead of tracing. So, to end tracing, we must asynchronously ask all
runtime overhead of tracing. So, to end tracing, we must asynchronously ask all
child processes to flush any pending trace data. child processes to flush any pending trace data.
Once all child processes have acked to the `stopRecording` request, `callback` Once all child processes have acked to the `stopRecording` request, `callback`
will be called back with a file that contains the traced data. will be called with a file that contains the traced data.
Trace data will be written into `resultFilePath` if it is not empty, or into a Trace data will be written into `resultFilePath` if it is not empty or into a
temporary file. The actual file path will be passed to `callback` if it's not temporary file. The actual file path will be passed to `callback` if it's not
null. `null`.
## tracing.startMonitoring(categoryFilter, traceOptions, callback) ### `tracing.startMonitoring(categoryFilter, traceOptions, callback)`
* `categoryFilter` String * `categoryFilter` String
* `traceOptions` String * `traceOptions` String
@ -97,22 +99,21 @@ null.
Start monitoring on all processes. Start monitoring on all processes.
Monitoring begins immediately locally, and asynchronously on child processes as Monitoring begins immediately locally and asynchronously on child processes as
soon as they receive the `startMonitoring` request. soon as they receive the `startMonitoring` request.
Once all child processes have acked to the `startMonitoring` request, Once all child processes have acked to the `startMonitoring` request the
`callback` will be called back. `callback` will be called.
## tracing.stopMonitoring(callback); ### `tracing.stopMonitoring(callback)`
* `callback` Function * `callback` Function
Stop monitoring on all processes. Stop monitoring on all processes.
Once all child processes have acked to the `stopMonitoring` request, `callback` Once all child processes have acked to the `stopMonitoring` request the `callback` is called.
is called back.
## tracing.captureMonitoringSnapshot(resultFilePath, callback) ### `tracing.captureMonitoringSnapshot(resultFilePath, callback)`
* `resultFilePath` String * `resultFilePath` String
* `callback` Function * `callback` Function
@ -121,22 +122,19 @@ Get the current monitoring traced data.
Child processes typically are caching trace data and only rarely flush and send Child processes typically are caching trace data and only rarely flush and send
trace data back to the main process. That is because it may be an expensive trace data back to the main process. That is because it may be an expensive
operation to send the trace data over IPC, and we would like to avoid unneeded operation to send the trace data over IPC and we would like to avoid unneeded
runtime overhead of tracing. So, to end tracing, we must asynchronously ask all runtime overhead from tracing. So, to end tracing, we must asynchronously ask all child processes to flush any pending trace data.
child processes to flush any pending trace data.
Once all child processes have acked to the `captureMonitoringSnapshot` request, Once all child processes have acked to the `captureMonitoringSnapshot` request the `callback` will be called with a file that contains the traced data.
the `callback` will be invoked with a file that contains the traced data.
## tracing.getTraceBufferUsage(callback) ### `tracing.getTraceBufferUsage(callback)`
* `callback` Function * `callback` Function
Get the maximum across processes of trace buffer percent full state. When the Get the maximum usage across processes of trace buffer as a percentage of the full state. When the TraceBufferUsage value is determined the `callback` is called.
TraceBufferUsage value is determined, the `callback` is called.
## tracing.setWatchEvent(categoryName, eventName, callback) ### `tracing.setWatchEvent(categoryName, eventName, callback)`
* `categoryName` String * `categoryName` String
* `eventName` String * `eventName` String
@ -145,7 +143,7 @@ TraceBufferUsage value is determined, the `callback` is called.
`callback` will will be called every time the given event occurs on any `callback` will will be called every time the given event occurs on any
process. process.
## tracing.cancelWatchEvent() ### `tracing.cancelWatchEvent()`
Cancel the watch event. If tracing is enabled, this may race with the watch Cancel the watch event. If tracing is enabled this may race with the watch
event callback. event callback.