Android性能优化（23）＊性能工具之「HeapViewer,MemoryMonitor,AllocationTracker」MemoryProfilers

　　In this document

• Memory Monitor
• Heap Viewer
• Allocation Tracker

　　You should also read

• Memory Monitor Walkthrough
• Heap Viewer Walkthrough
• Allocation Tracker Walkthrough

1.简介

• Provides a quick way to test whether app slowness might be related to excessive GC events.

  可测试是否由于过多的GC导致应用变慢。

• Provides a quick way to see whether app crashes might be related to running out of memory.

  检查是否由于内存不足导致应用崩溃。

• Runs live on your application and updates about once a second.
• Helps quickly identify the potential of memory leaks.

  标识潜在的内存泄漏。

• Helps identify GC patterns for your application and determine whether they are healthy and what you expect.

  标识GC运行是否健康。

• Is easy to use, and it is easy to interpret what you see.
• However, Memory Monitor does not tell you which objects are the cause of your problems, or where in your code it might be.

  它的缺点是并不能指出是哪个对象有问题，哪句代码有问题。

　　　　　　Figure 1. Memory Monitor.

3.Heap Viewer

• Shows snapshots of a number of objects allocated by type.
• Samples data every time a garbage collection event occurs naturally or triggered by you.

  采集每次自动或手动GC的对象。

• Helps identify which object types might be involved in memory leaks.

  标识出哪些对象可能与内存泄漏有关。

• However, you have to look for changes over time yourself by tracking what's happening in the graph.

4.Allocation Tracker 

• Shows when and where your code allocates object types, their size, allocating thread, and stack traces.

  记录内存分配信息。

• Helps recognize memory churn through recurring allocation/deallocation patterns.

  识别重复无效的内存分配。

• Can be used in combination with Heap Viewer to track down memory leaks. For example, if you see a bitmap object resident on the heap, you can find its allocation location with Allocation Tracker.

  帮助Heap Viewer, Memory Monitor 分析内存泄漏。

• However, it takes time and experience to learn to interpret the output from this tool.