mirror of https://github.com/lukechilds/node.git
Timothy J Fontaine
11 years ago
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# Tracing |
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Stability: 1 - Experimental |
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The tracing module is designed for instrumenting your Node application. It is |
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not meant for general purpose use. |
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***Be very careful with callbacks used in conjunction with this module*** |
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Many of these callbacks interact directly with asynchronous subsystems in a |
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synchronous fashion. That is to say, you may be in a callback where a call to |
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`console.log()` could result in an infinite recursive loop. Also of note, many |
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of these callbacks are in hot execution code paths. That is to say your |
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callbacks are executed quite often in the normal operation of Node, so be wary |
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of doing CPU bound or synchronous workloads in these functions. Consider a ring |
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buffer and a timer to defer processing. |
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`require('tracing')` to use this module. |
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## v8 |
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The `v8` property is an [EventEmitter][], it exposes events and interfaces |
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specific to the version of `v8` built with node. These interfaces are subject |
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to change by upstream and are therefore not covered under the stability index. |
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### Event: 'gc' |
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`function (before, after) { }` |
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Emitted each time a GC run is completed. |
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`before` and `after` are objects with the following properties: |
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``` |
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{ |
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type: 'mark-sweep-compact', |
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flags: 0, |
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timestamp: 905535650119053, |
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total_heap_size: 6295040, |
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total_heap_size_executable: 4194304, |
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total_physical_size: 6295040, |
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used_heap_size: 2855416, |
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heap_size_limit: 1535115264 |
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} |
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``` |
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### getHeapStatistics() |
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Returns an object with the following properties |
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``` |
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{ |
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total_heap_size: 7326976, |
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total_heap_size_executable: 4194304, |
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total_physical_size: 7326976, |
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used_heap_size: 3476208, |
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heap_size_limit: 1535115264 |
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} |
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``` |
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[EventEmitter]: events.html#events_class_events_eventemitter |
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