移动地图时，Xcode 9模拟器上的GoogleMaps使用了超过100％的CPU [英] GoogleMaps on simulator in Xcode 9 uses over 100% of CPU when moving the map

问题描述

因此，我现在已经将我的项目转换为在Xcode 9中使用Swift 4，并且已经开始测试我的应用程序。这是一个包含四个不同标签的大应用程序，几乎所有内容都按预期工作。其中一个标签是使用GoogleMaps的地图。我从来没有遇到任何问题，但是当使用Xcode 9构建并在Simulator中显示时，它在移动地图时使用了100％以上的CPU，并且它非常滞后。
这是在模拟器上运行时的调试导航器。
我们做了一些自定义绘图，但没有102％的绘图。

这只在我更新到Xcode 9和Swift 4后才开始发生。
在iPhone 7,8或X 模拟器的Xcode 9中进行调试时，所有使用iOS 11，它只有100％以上的CPU，并且每当我尝试移动它时，它都会使UI停止更新大约一秒钟。我开始拖动手势，但UI只更新一次。有效地给我介绍 1fps 。

然而，在iPhone 6 模拟器上在Xcode 9中进行调试时与 iOS 9 相比，移动地图时可达到约90％，而且几乎没有滞后。我猜我在这里得到20-30 fps。 （这可能与我在Xcode 8上的模拟器中获得的fps相同。）模拟器上的地图从未真正流畅。）当在实际设备上运行时（iPhone 7 ，iOS 11）时，CPU在不断移动地图时使用约40％，并且工作非常流畅，根本没有滞后（60fps）。

我也得到这个在输出结果中，只要我用地图打开标签，但我认为它与这个特定问题无关：

 主线程检查器：在后台线程上调用UI API： -  [UIApplication applicationState] 
 PID：*****，TID：*******，线程名称：com.google.Maps.LabelingBehavior，队列名称：com.apple.root.default-qos.overcommit，QoS：21 
  

这表示GoogleMapsAPI调用 [UIApplication applicationState] 在后台线程上。

我使用最新版GoogleMaps： 2.4.0 即可。据我所知，这个版本可能不支持Xcode 9 / Swift 4等，但我找不到任何有关新版本的信息。 div> 更新：在Xcode 9.1 beta 2中修正了这个问题。

在 OpenGLES .framework 导致它跳过加载LLVM JIT并回退到解释着色器。这对模拟器有着严重的性能影响，因为它完全是软件渲染的OpenGL（包括CoreAnimation，SceneKit等）。

编辑 ：为了澄清，这些症状正是您所描述的：100％或更高的CPU使用率和<1fps的渲染。这会影响Google Maps SDK和MapKit。

作为临时解决方法，您可以从Beta 3中复制 libCoreVMClient.dylib 进入Xcode 9 GM，性能应该恢复到之前的水平。对于iOS，它位于： Xcode [-beta] .app / Contents / Developer /平台/ iPhoneOS.platform /开发/库/ CoreSimulator /概况/运行时/ iOS.simruntime /内容/资源/ RuntimeRoot /系统/资源库/框架/ OpenGLES.framework / libCoreVMClient.dylib

对于tvOS，它位于： Xcode [-beta] .app / Contents / Developer / Platforms / AppleTVOS.platform / Developer / Library / CoreSimulator / Profiles / Runtime / tvOS.simruntime / Contents / Resources / RuntimeRoot / System / Library / Frameworks / OpenGLES.framework / libCoreVMClient.dylib

位于： Xcode [-beta] .app / Contents / Developer / Platforms / WatchOS.platform / Developer / Library / CoreSimulator / Profiles / Runtimes / watchOS.simruntime / Contents / Resources / RuntimeRoot / System / Library / Frameworks / OpenGLES.framework / libCoreVMClient.dylib

So I've now converted my project to use Swift 4 in Xcode 9, and have started testing my app. It's a big app with four distinct tabs, and nearly everything is working as expected. One of the tabs is a map, using GoogleMaps. I have never had any trouble with it, but when built with Xcode 9 and shown in Simulator, it uses over 100% of CPU when moving the map, and it lags very much. Here is the debug navigator when running on a simulator. We do some custom drawing, but not 102% worth of drawing.

This only started happening after I updated to Xcode 9 and Swift 4. When debugging in Xcode 9 on an iPhone 7, 8 or X simulator, all with iOS 11, it goes just over 100% CPU, and it completely stops the UI from updating for about one second each time I try to move it. I start the drag-gesture, but the UI only updates once a second. Effectively giving me about 1fps.

However, when debugging in Xcode 9 on an iPhone 6 simulator with iOS 9, it gets up to ~90% when moving the map and not lagging nearly as much. I'm guessing I get about 20-30 fps here. (This might be the same fps I get in simulators on Xcode 8. Map has never been really smooth on simulator..)

When running on an actual device (iPhone 7, iOS 11), the CPU uses about 40% when constantly moving the map, and is working very smooth with no lags at all (60fps).

I also get this in the output as soon as I open the tab with the map, but I think it's irrelevant to this particular question:

Main Thread Checker: UI API called on a background thread: -[UIApplication applicationState]
PID: *****, TID: *******, Thread name: com.google.Maps.LabelingBehavior, Queue name: com.apple.root.default-qos.overcommit, QoS: 21

This says that GoogleMapsAPI calls [UIApplication applicationState] on a background thread..

I am using the latest version of GoogleMaps: 2.4.0. As far as I know, this version may not support Xcode 9/Swift 4 etc, but I can't find anything about a new version.

解决方案

Update: This issue is fixed in Xcode 9.1 beta 2

There is a bug in OpenGLES.framework that causes it to skip loading the LLVM JIT and fall back to interpreting shaders. This has a severe performance impact on the Simulator since it is entirely software-rendered OpenGL (this includes CoreAnimation, SceneKit, etc).

edit: To clarify, the symptoms of this are exactly what you describe: 100% or greater CPU usage and <1fps rendering. This affects the Google Maps SDK and MapKit.

As a temporary workaround you can copy libCoreVMClient.dylib from Beta 3 into the Xcode 9 GM and performance should be restored to what it was previously. This must be done for each platform runtime separately.

For iOS this is located at: Xcode[-beta].app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/Library/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/Frameworks/OpenGLES.framework/libCoreVMClient.dylib

For tvOS this is located at: Xcode[-beta].app/Contents/Developer/Platforms/AppleTVOS.platform/Developer/Library/CoreSimulator/Profiles/Runtimes/tvOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/Frameworks/OpenGLES.framework/libCoreVMClient.dylib

For watchOS this is located at: Xcode[-beta].app/Contents/Developer/Platforms/WatchOS.platform/Developer/Library/CoreSimulator/Profiles/Runtimes/watchOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/Frameworks/OpenGLES.framework/libCoreVMClient.dylib

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