[GitHub] [incubator-mxnet] Zha0q1 commented on a change in pull request #15403: Updating profiler tutorial to include new custom operator profiling

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Zha0q1 commented on a change in pull request #15403: Updating profiler tutorial to include new custom operator profiling
URL: https://github.com/apache/incubator-mxnet/pull/15403#discussion_r298816908
 
 

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 File path: docs/tutorials/python/profiler.md
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 @@ -206,6 +206,15 @@ Let's zoom in to check the time taken by operators
 
 The above picture visualizes the sequence in which the operators were executed and the time taken by each operator.
 
+### Profiling Custom Operators
+Should the existing NDArray operators fail to meet all your model's needs, MXNet supports [Custom Operators](https://mxnet.incubator.apache.org/versions/master/tutorials/gluon/customop.html) that you can define in Python. In `forward()` and `backward()` of a custom operator, there are two kinds of code: "pure Python" code (NumPy operators included) and "sub-operators" (NDArray operators called within `forward()` and `backward()`). With that said, MXNet can profile the execution time of both kinds without additional setup. Specifically, the MXNet profiler will break a single custom operator call into a pure Python event and several sub-operator events if there are any. Furthermore, all of those events will have a prefix in their names, which is, conveniently, the name of the custom operator you called.
+
+![Custom Operator Profiling Screenshot](https://cwiki.apache.org/confluence/download/attachments/118172065/image2019-6-14_15-23-42.png?version=1&modificationDate=1560551022000&api=v2)
+
+As shown by the screenshot, in the **Custom Operator** domain where all the custom operator-related events fall into, you can easily visualize the execution time of each segment of your custom operator. For example, we know that `CustomAddTwo::sqrt` is a sub-operator of custom operator `CustomAddTwo`, and we also know when it is executed accurately.
+
+Please note that: to be able to see the previously described information, you need to set `profile_imperative` to `True` even when you are using custom operators in [symbolic mode](https://mxnet.incubator.apache.org/versions/master/tutorials/basic/symbol.html). The reason is that within custom operators, pure python code and sub-operators are still called imperatively.  
 
 Review comment:
   I have created a new example and updated here accordingly. Now we have both code and screenshot

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