UE4 LLM工具
LLM(Low Level Memory Tracker) 是从 4.18 开始引入的新的内存统计工具，比memreport 统计数据更加详细精确，但又不会像 MallocProfiler 那样有很大的本身开销
通过LLM，可以知道游戏消耗的内存分别来自引擎的哪些模块，让开发者可以对内存占用高的模块进行有针对性优化。
Debug、Development包才会启用ENABLE_LOW_LEVEL_MEM_TRACKER宏，统计逻辑才会编译进可执行二进制中，才能使用LLM相关的功能
Shipping包是没有LLM功能，对于Test包可以#define ALLOW_LOW_LEVEL_MEM_TRACKER_IN_TEST 1来将LLM代码编译进包
相关逻辑在UnrealEngine\Engine\Source\Runtime\Core\Public\HAL\LowLevelMemTracker.h、UnrealEngine\Engine\Source\Runtime\Core\Private\HAL\LowLevelMemTracker.cpp文件中
LLM通过插入各种tag来将所有待统计的内存划归到某个tag下。实现原理是：插入的tag会形成一个tag的栈，将FMalloc分配的内存统计到当前栈顶的tag下（离FMalloc分配最近的一个tag）。
LLM在最底层hook了FMalloc的每一个统计，如果没有任何tag在当前栈中，那么所有内存计入在untagged这个tag下。LLM通过TLS机制来实现tag多线程安全读写，避免了不必要的锁机制，提升效率。
如果我们在代码中插入一个基于scoped的tag，就可以把这个scope下的独占内存（Exclusive）计入这个tag下。通过LLM我们不会遗漏任何FMalloc分配的内存。
此外程序刚初始化，加载libUE4.so时，LLM会记录一个内存，被它估计为可执行程序本身的内存，记在ProgramSize这个tag中。
在RHI中对gpu资源的创建也会被LLM记录 ，在额外的texture，buffer等标签下，它们不是FMalloc内存的一部分，是对GPU的内存占用的估算。
LLM目前有两个Tracker（跟踪器）：Default Tracker（默认跟踪器）和Platform Tracker（平台跟踪器）。它们都有自己的独立分配映射和标记堆栈。
Default Tracker（ELLMTracker::Default）的级别较高，记录引擎中FMemory的Malloc函数进行的分配。为 stat LLM和 stat LLMFULL控制台命令提供统计信息。
Platform Tracker（ELLMTracker::Platform）的级别较低，记录从OS进行的所有分配。例如，它会跟踪FMemory的Malloc函数进行的内部分配。因此，Default Tracker是Platform Tracker统计信息的子集。
运行开关
在编译时打开 LLM 后，要想在运行时使用 LLM 的功能，还要加上启动命令行 -LLM -LLMCSV
-LLM：运行时打开LLM统计 或者通过定义#define LLM_AUTO_ENABLE 1默认打开 注：开了之后会导致fps下降23.7%，对性能影响很大
-LLMCSV：将内存统计信息输出到CSV 文件中，CSV 文件保存在 Saved\Profiling\LLM 目录下 注：设置控制台变量LLM.LLMWriteInterval xx，修改写csv文件的频率为xx秒，默认5秒写一行
会得到两个 csv 文件，一个是 LLM_ 前缀，另一个是 LLMPlatform_前缀，这两个文件分别由两个 Tracker 生成，这两个文件的关注点不同
① LLM 主要关注FMalloc内存的消费者，主要就是引擎内各个部分的内存开销
② LLMPlatform 只关注系统内存的消费者，主要有几大类: ProgramSize, FMalloc, LLMOverhead
注：开启了csv写入，每写入一行也会打印log
。。。 [2023.05.19-15.48.16:537][ 792]LogHAL: Display: |LowLevelMemTracker.cpp:2596|Wrote LLM csv line 10 [2023.05.19-15.48.16:539][ 792]LogHAL: Display: |LowLevelMemTracker.cpp:2596|Wrote LLM csv line 10 [2023.05.19-15.48.21:542][ 877]LogHAL: Display: |LowLevelMemTracker.cpp:2596|Wrote LLM csv line 11 [2023.05.19-15.48.21:545][ 877]LogHAL: Display: |LowLevelMemTracker.cpp:2596|Wrote LLM csv line 11 [2023.05.19-15.48.26:562][ 1092]LogHAL: Display: |LowLevelMemTracker.cpp:2596|Wrote LLM csv line 12 [2023.05.19-15.48.26:565][ 1092]LogHAL: Display: |LowLevelMemTracker.cpp:2596|Wrote LLM csv line 12 [2023.05.19-15.48.31:578][ 1332]LogHAL: Display: |LowLevelMemTracker.cpp:2596|Wrote LLM csv line 13 [2023.05.19-15.48.31:580][ 1332]LogHAL: Display: |LowLevelMemTracker.cpp:2596|Wrote LLM csv line 13 [2023.05.19-15.48.36:578][ 1582]LogHAL: Display: |LowLevelMemTracker.cpp:2596|Wrote LLM csv line 14 [2023.05.19-15.48.36:581][ 1582]LogHAL: Display: |LowLevelMemTracker.cpp:2596|Wrote LLM csv line 14 [2023.05.19-15.48.41:586][ 1830]LogHAL: Display: |LowLevelMemTracker.cpp:2596|Wrote LLM csv line 15 [2023.05.19-15.48.41:589][ 1830]LogHAL: Display: |LowLevelMemTracker.cpp:2596|Wrote LLM csv line 15 [2023.05.19-15.48.46:595][ 2079]LogHAL: Display: |LowLevelMemTracker.cpp:2596|Wrote LLM csv line 16 [2023.05.19-15.48.46:599][ 2079]LogHAL: Display: |LowLevelMemTracker.cpp:2596|Wrote LLM csv line 16 。。。
-LLMTAGSETS=Assets：显示每个资源分配的统计，不只是有大类别的数据。 注：需打开LLM_ALLOW_ASSETS_TAGS 宏
-LLMTAGSETS=AssetClasses：按UObject类别进行分类统计
注：写CSV时，如果开启了-LLMTAGSETS 命令行，CSV 文件可能会错乱。
因为写 CSV 文件时预留了第一行标题栏内容的缓冲区，当每个资源或资源类很多，会导致标题栏内容溢出，覆盖了后面的数据区域，所以这里需要自己按需求修改一下
具体的控制台命令为：LLM.LLMHeaderMaxSize 500000
运行时开关 LLM 的处理见 FLowLevelMemTracker::ProcessCommandLine 函数
在UE4CommandLine.txt文件中添加命令行参数：
../../../MyGame/MyGame.uproject -LLM -LLMCSV
Android需要将该文件push到手机的UE4Game/MyGame/UE4CommandLine.txt
iOS需要将ue4commandline.txt（注：需要全小写）放在如下目录中：
从csv生成html图表
PerfreportTool.exe -csv F:\UAGame\Saved\Profiling\LLM\LLM_Pid23989_2021.03.30-14.14.55.csv -o c:\LLMOutput -reporttype LLM -topng. -graphxml LLMReportGraphs.xml -reportxml LLMReportTypes.xml -nostripevents
PerfreportTool.exe -csv F:\UAGame\Saved\Profiling\LLM\LLMPlatform_Pid23989_2021.03.30-14.14.55.csv -o c:\LLMOutput -reporttype LLM -topng. -graphxml LLMReportGraphs.xml -reportxml LLMReportTypes.xml -nostripevents
生成的html文件如下：
统计项说明
Android
LLM_Pid23989_2021.03.30-14.14.55内容如下：
Untagged,RenderingThread,Audio/AudioMisc,EngineInit,Stats,LoadMapMisc,Audio/AudioMixer,GC,Audio,AsyncLoading,UObject,FileSystem,Materials,Shaders,TextureMetaData,InitUObject,UI,EnginePreInit,Textures,Meshes,SceneRender,RenderTargets,RHIMisc,Meshes/StaticMesh,FName,MaterialInstance,PSO,Particles,Localization,ConfigSystem,TaskGraphMiscTasks,Physics/PhysXAllocator,Physics,AssetRegistry,CsvProfiler,Audio/AudioMixerPlugins,Physics/PhysX,NavigationRecast,EngineMisc,ProgramSize,GenericPlatformMallocCrash,FMallocUnused,TrackedTotal,Total,Untracked,StreamingManager,Lua,Meshes/Landscape,Animation,Meshes/SkeletalMesh,Niagara,MediaStreaming,Meshes/InstancedMesh,Physics/PhysXLandscape,Audio/AudioSynthesis, 。。。 。。。 35.32,6.21,0.02,0.90,21.65,5.05,9.52,0.62,9.55,3.08,105.19,13.72,0.54,19.11,0.65,12.84,42.70,18.71,67.28,31.85,34.72,40.85,0.80,8.79,7.12,0.31,0.15,0.78,36.59,2.80,0.00,6.32,6.71,0.13,0.00,0.00,0.39,0.71,3.78,157.18,3.61,55.31,789.20,830.58,41.44,0.44,28.88,0.03,13.38,12.33,0.00,0.00,0.13,0.00,0.00, 35.32,6.21,0.02,0.90,21.52,5.05,9.52,0.62,9.55,3.08,105.22,13.72,0.54,19.11,0.65,12.84,42.71,18.71,67.28,31.78,34.25,40.85,0.80,8.79,7.12,0.31,0.15,0.78,36.59,2.80,0.00,6.33,6.71,0.13,0.00,0.00,0.39,0.71,3.78,157.18,3.61,56.45,789.74,842.68,52.88,0.44,28.91,0.03,13.38,12.27,0.00,0.00,0.13,0.00,0.00, 35.32,6.21,0.02,0.90,21.65,5.05,9.52,0.62,9.55,3.08,105.22,13.72,0.54,19.11,0.65,12.84,42.74,18.71,67.28,31.89,34.99,40.85,0.80,8.79,7.12,0.31,0.15,0.78,36.59,2.80,0.00,6.34,6.73,0.13,0.00,0.00,0.39,0.71,3.79,157.18,3.61,55.68,790.05,828.77,38.50,0.44,28.94,0.03,13.38,12.37,0.00,0.00,0.13,0.00,0.00, 35.32,6.21,0.02,0.90,21.59,5.05,9.52,0.62,9.55,3.08,105.25,13.72,0.54,19.11,0.65,12.84,42.72,18.71,67.28,31.86,35.13,40.85,0.80,8.79,7.12,0.31,0.15,0.78,36.59,2.80,0.00,6.32,6.71,0.13,0.00,0.00,0.39,0.71,3.81,157.18,3.61,55.56,790.05,841.99,52.15,0.44,28.96,0.03,13.44,12.34,0.00,0.00,0.13,0.00,0.00, 35.32,6.21,0.02,0.90,21.40,5.05,9.52,0.65,9.55,3.08,105.18,13.72,0.54,19.11,0.65,12.84,42.72,18.71,67.28,31.32,35.28,40.85,0.80,8.79,7.12,0.31,0.15,0.78,36.59,2.80,0.00,6.34,6.73,0.13,0.00,0.00,0.39,0.71,3.77,157.18,3.61,54.50,788.20,838.28,50.08,0.44,28.99,0.03,13.26,11.80,0.00,0.00,0.13,0.00,0.00, 35.32,6.21,0.02,0.90,21.84,5.05,9.52,0.65,9.55,3.08,105.18,13.72,0.54,19.11,0.65,12.84,42.74,18.71,67.28,31.59,35.64,40.85,0.80,8.79,7.12,0.31,0.15,0.78,36.59,2.80,0.00,6.34,6.73,0.13,0.00,0.00,0.39,0.71,3.77,157.18,3.61,55.04,789.89,837.26,46.91,0.44,29.02,0.03,13.26,12.07,0.00,0.00,0.13,0.00,0.00, 35.32,6.21,0.02,0.90,22.03,5.05,9.52,0.65,9.55,3.08,105.17,13.72,0.54,19.11,0.65,12.84,42.75,18.71,67.28,31.52,35.90,40.85,0.80,8.79,7.12,0.31,0.15,0.78,36.59,2.80,0.00,6.34,6.73,0.13,0.00,0.00,0.39,0.71,3.74,157.18,3.61,54.95,790.17,831.60,40.49,0.44,29.05,0.03,13.26,11.96,0.00,0.00,0.13,0.00,0.00, 35.32,6.21,0.02,0.90,21.46,5.05,9.52,0.65,9.55,3.08,105.19,13.72,0.54,19.11,0.65,12.84,42.73,18.71,67.28,31.74,35.36,40.85,0.80,8.79,7.12,0.31,0.15,0.78,36.59,2.80,0.00,6.34,6.73,0.13,0.00,0.00,0.39,0.71,3.75,157.18,3.61,55.90,790.32,843.07,53.02,0.44,29.07,0.03,13.31,12.22,0.00,0.00,0.13,0.00,0.00, 35.32,6.21,0.02,0.90,21.46,5.05,9.52,0.65,9.55,3.08,105.22,13.72,0.54,19.11,0.65,12.84,42.74,18.71,67.28,31.82,35.44,40.85,0.80,8.79,7.12,0.31,0.15,0.78,36.59,2.80,0.00,6.34,6.73,0.13,0.00,0.00,0.39,0.71,3.77,157.18,3.61,56.08,790.86,843.15,52.41,0.44,29.23,0.03,13.32,12.30,0.00,0.00,0.13,0.00,0.00, 35.32,6.21,0.02,0.90,21.78,5.05,9.52,0.65,9.55,3.08,105.23,13.72,0.54,19.11,0.65,12.84,42.75,18.71,67.28,31.71,36.19,40.85,0.80,8.79,7.12,0.31,0.15,0.78,36.59,2.80,0.00,6.33,6.72,0.13,0.00,0.00,0.39,0.71,3.77,157.18,3.61,55.50,791.27,842.89,51.62,0.44,29.26,0.03,13.32,12.18,0.00,0.00,0.13,0.00,0.00,
Total（830.58） = TrackedTotal（789.2） + Untracked（41.44）
TrackedTotal（789.2） = Untagged（35.32） + RenderingThread（6.21） + EngineInit（0.9） + Stats（21.65） + LoadMapMisc（5.05） + GC（0.62） + Audio（9.55） + AsyncLoading（3.08） + UObject（105.19） + FileSystem（13.72）+ Materials（0.54）
+ Shaders（19.11） + TextureMetaData（0.65） + InitUObject（12.84） + UI（42.7） + EnginePreInit（18.71） + Textures（67.28） + Meshes（31.85） + SceneRender（34.72） + RenderTargets（40.85） + RHIMisc（0.8） + FName（7.12）
+ MaterialInstance（0.31） + PSO（0.15） + Particles（0.78） + Localization（36.59） + ConfigSystem（2.8） + TaskGraphMiscTasks（0）+ Physics（6.71） + AssetRegistry（0.13） + CsvProfiler（0） + NavigationRecast（0.71）
+ EngineMisc（3.78） + ProgramSize（157.18） + GenericPlatformMallocCrash（3.61） + FMallocUnused（55.31） + StreamingManager（0.44） + Lua（28.88） + Animation（13.38） + Niagara（0） + MediaStreaming（0）
Meshes（31.85） > Meshes/StaticMesh（8.79） + Meshes/Landscape（0.03） + Meshes/InstancedMesh（0.13） + Meshes/SkeletalMesh（12.33）
Physics（6.71） = Physics/PhysXAllocator（6.32） + Physics/PhysX（0.39） + Physics/PhysXLandscape（0）
Audio（9.55） = Audio/AudioMisc（0.02） + Audio/AudioMixer（9.52） + Audio/AudioMixerPlugins（0） + Audio/AudioSynthesis（0）
注1：Audio内存占用，可在DefaultEngine.ini中关闭掉
[Audio] UseAudioMixer=False
注2：带上-NoAudioMixer命令行参数
LLMPlatform_Pid23989_2021.03.30-14.14.55.csv内容如下：
Untagged,FMalloc,Graphics,ProgramSize,GenericPlatformMallocCrash,TrackedTotal,Total,Untracked,LLMOverhead,OSAvailable, 。。。 。。。 0.00,511.05,115.27,157.18,3.61,918.22,961.69,43.47,131.11,3389.45, 0.00,511.61,115.27,157.18,3.61,907.32,962.20,54.88,119.64,3388.55, 0.00,511.86,115.28,157.18,3.61,920.53,961.36,40.84,132.58,3387.90, 0.00,511.86,115.27,157.18,3.61,907.62,961.63,54.02,119.69,3386.14, 0.00,510.05,115.27,157.18,3.61,905.81,957.96,52.16,119.69,3389.23, 0.00,511.74,115.27,157.18,3.61,907.49,956.95,49.46,119.69,3387.49, 0.00,511.99,115.31,157.18,3.61,919.30,962.82,43.52,131.22,3385.75, 0.00,512.18,115.27,157.18,3.61,907.96,962.80,54.84,119.72,3388.29, 0.00,512.68,115.27,157.18,3.61,908.46,962.87,54.41,119.72,3386.87, 0.00,513.11,115.27,157.18,3.61,908.93,962.64,53.72,119.75,3386.62,
Total（961.69） = TrackedTotal（918.22） + Untracked（43.47）
TrackedTotal（918.22） = Untagged（0.00） + FMalloc（511.05） + Graphics（115.27） + ProgramSize（157.18） + GenericPlatformMallocCrash（3.61） + LLMOverhead（131.11）
IOS
LLM_Pid0_2021.09.27-19.41.13.csv内容如下：
Untagged,Stats,EngineInit,RenderingThread,AsyncLoading,UObject,FileSystem,Materials,Shaders,TextureMetaData,FName,InitUObject,Wwise,EnginePreInit,UI,Textures,Metal Textures,Metal Buffers,SceneRender,RenderTargets,RHIMisc,Meshes/StaticMesh,PSO,MaterialInstance,LoadMapMisc,Particles,GC,Meshes,Localization,ConfigSystem,TaskGraphMiscTasks,Physics/PhysXAllocator,AssetRegistry,CsvProfiler,Physics/PhysX,NavigationRecast,EngineMisc,Physics,ProgramSize,FMallocUnused,TrackedTotal,Total,Untracked,StreamingManager,Meshes/Landscape,Lua,Animation,UI/Font,Meshes/InstancedMesh,Meshes/SkeletalMesh,Audio/AudioSoundWaves,Niagara,MediaStreaming,GCloud,Networking,Textures/MergeTexture,Physics/PhysXLandscape, 。。。 。。。 9.39,12.94,1.13,1.22,4.16,93.28,17.82,0.28,20.41,0.53,11.50,13.35,8.13,2.47,34.46,0.56,0.10,0.12,2.62,0.01,0.65,1.23,14.10,0.29,0.97,2.05,7.74,13.00,12.56,3.55,0.00,25.29,0.89,0.00,0.46,0.07,10.36,25.76,29.87,-42.96,363.24,847.58,484.39,0.28,0.00,47.04,2.11,0.89,0.05,11.73,0.00,0.03,0.00,0.05,0.30,0.00,0.01, 9.39,13.13,1.13,1.22,4.16,93.28,17.82,0.28,20.41,0.53,11.50,13.35,8.13,2.47,34.46,0.56,0.10,0.12,2.62,0.01,0.65,1.24,14.10,0.29,0.97,2.05,7.74,13.01,12.56,3.55,0.00,25.29,0.89,0.00,0.46,0.07,10.36,25.76,29.87,-42.98,363.42,847.71,484.25,0.28,0.00,47.06,2.11,0.89,0.05,11.73,0.00,0.03,0.00,0.05,0.30,0.00,0.01, 9.39,12.88,1.13,1.22,4.16,93.28,17.82,0.28,20.41,0.53,11.50,13.35,8.13,2.47,34.47,0.56,0.10,0.12,2.59,0.01,0.65,1.20,14.10,0.29,0.97,2.05,7.74,12.95,12.56,3.55,0.00,25.29,0.89,0.00,0.46,0.07,10.36,25.75,29.87,-42.92,363.15,847.51,484.38,0.28,0.00,47.08,2.11,0.89,0.05,11.71,0.00,0.03,0.00,0.05,0.30,0.00,0.01, 9.39,13.00,1.13,1.22,4.16,93.28,17.82,0.28,20.41,0.53,11.50,13.35,8.13,2.47,34.47,0.56,0.10,0.12,2.66,0.01,0.65,1.20,14.10,0.29,0.97,2.05,7.74,12.97,12.56,3.55,0.00,25.29,0.89,0.00,0.46,0.07,10.36,25.75,29.87,-43.02,363.27,847.60,484.24,0.28,0.00,47.10,2.11,0.89,0.05,11.72,0.00,0.03,0.00,0.05,0.30,0.00,0.01, 9.39,12.88,1.13,1.22,4.16,93.28,17.82,0.28,20.41,0.53,11.50,13.35,8.13,2.47,34.47,0.56,0.10,0.12,2.62,0.01,0.65,1.24,14.10,0.29,0.97,2.05,7.74,13.01,12.56,3.55,0.00,25.29,0.89,0.00,0.46,0.07,10.36,25.76,29.87,-43.05,363.18,847.52,484.31,0.28,0.00,47.12,2.11,0.89,0.05,11.74,0.00,0.03,0.00,0.05,0.30,0.00,0.01, 9.39,13.10,1.13,1.22,4.17,99.00,17.82,0.28,20.41,0.54,11.50,13.76,8.19,2.48,44.66,0.57,0.10,0.12,2.61,0.01,0.65,1.27,14.10,0.29,0.97,2.05,7.74,13.03,14.75,3.55,0.00,25.29,0.89,0.00,0.46,0.07,10.42,25.75,29.87,-53.73,373.40,858.88,485.47,0.28,0.00,49.14,2.11,0.89,0.05,11.72,0.00,0.03,0.00,0.05,0.30,0.00,0.01, 9.39,13.04,1.13,1.22,4.17,99.02,17.82,0.28,20.41,0.54,11.50,13.76,8.16,2.48,44.67,0.57,0.10,0.12,2.65,0.01,0.65,1.20,14.10,0.29,0.97,2.05,7.74,12.96,14.75,3.55,0.00,25.29,0.89,0.00,0.46,0.07,10.46,25.75,29.87,-53.91,373.50,861.30,487.85,0.28,0.00,49.49,2.11,0.89,0.05,11.72,0.00,0.03,0.00,0.05,0.30,0.00,0.01, 9.39,12.79,1.13,1.22,4.17,99.10,17.82,0.28,20.41,0.54,11.50,13.76,8.13,2.48,44.87,0.57,0.10,0.12,2.65,0.01,0.65,1.27,14.10,0.29,0.97,2.05,7.74,13.04,14.79,3.55,0.00,25.29,0.89,0.00,0.46,0.07,10.50,25.76,29.87,-55.87,373.64,861.69,488.01,0.28,0.00,51.43,2.11,0.89,0.05,11.72,0.00,0.03,0.00,0.05,0.30,0.00,0.01, 9.39,12.98,1.13,1.22,4.17,99.10,17.82,0.28,20.41,0.54,11.50,13.76,8.14,2.48,44.86,0.57,0.10,0.12,2.65,0.01,0.65,1.25,14.10,0.29,0.97,2.05,7.74,13.01,14.79,3.55,0.00,25.29,0.89,0.00,0.46,0.07,10.50,25.76,29.87,-55.93,373.84,861.91,488.08,0.28,0.00,51.52,2.11,0.89,0.05,11.72,0.00,0.03,0.00,0.05,0.30,0.00,0.01,
Total（847.58） = TrackedTotal（363.24） + Untracked（484.39）
TrackedTotal（363.24） = Untagged（9.39） + Stats（12.94） + EngineInit（1.13） + RenderingThread（1.22） + AsyncLoading（4.16） + UObject（93.28） + FileSystem（17.82） + Materials（0.28） + Shaders（20.41） + TextureMetaData（0.53）
+ FName（11.5）+ InitUObject（13.35） + Wwise（8.13） + EnginePreInit（2.47） + UI（34.46） + Textures（0.56） + Metal Textures（0.1） + Metal Buffers（0.12） + SceneRender（2.62） + RenderTargets（0.01） + RHIMisc（0.65） + PSO（14.1）
+ MaterialInstance（0.29）+ LoadMapMisc（0.97）+ Particles（2.05）+ GC（7.74）+ Meshes（13）+ Localization（12.56）+ ConfigSystem（3.55）+ TaskGraphMiscTasks（0）+ AssetRegistry（0.89）+ CsvProfiler（0）+ NavigationRecast（0.07）
+ EngineMisc（10.36） + Physics（25.76） + ProgramSize（29.87） + FMallocUnused（-42.96） + StreamingManager（0.28） + Lua（47.04） + Animation（2.11） + Niagara（0.03） + MediaStreaming（0） + GCloud（0.05） + Networking（0.3）
Meshes（13） = Meshes/StaticMesh（1.23） + Meshes/Landscape（0） + Meshes/InstancedMesh（0.05） + Meshes/SkeletalMesh（11.73）
Physics（25.76） = Physics/PhysXAllocator（25.29） + Physics/PhysX（0.46） + Physics/PhysXLandscape（0.01）
LLMPlatform_Pid0_2021.09.27-19.41.13.csv内容如下：
Virtual Memory,Untagged,FMalloc,Metal Textures,Metal Buffers,Metal Render Targets,ProgramSize,TrackedTotal,Total,Untracked,LLMOverhead,OSAvailable,MMIO, 。。。 。。。 400460.56,1.05,333.55,87.24,17.30,156.70,29.87,800.97,1010.75,209.78,163.04,1088.45,12.22, 400451.62,1.05,333.30,87.24,17.30,156.70,29.87,800.72,1010.55,209.83,163.04,1088.65,12.22, 400450.56,1.05,333.42,87.24,17.30,156.70,29.87,800.84,1010.64,209.80,163.04,1088.56,12.22, 400450.50,1.05,333.30,87.24,17.34,156.70,29.87,800.76,1010.56,209.80,163.04,1088.64,12.22, 400456.47,1.05,343.53,87.82,17.25,156.70,29.87,811.49,1021.92,210.43,163.04,1077.28,12.22, 400458.53,1.05,343.62,87.82,17.34,156.70,29.87,808.43,1021.09,212.67,159.79,1078.11,12.22, 400460.06,1.05,343.77,87.82,17.34,156.70,29.87,808.57,1021.48,212.92,159.79,1077.72,12.22, 400453.75,1.05,343.97,87.82,17.34,156.70,29.87,808.77,1021.70,212.93,159.79,1077.50,12.22, 400454.81,1.05,343.78,87.82,17.30,156.70,29.87,808.54,1021.56,213.03,159.79,1077.64,12.22, 400459.12,1.05,343.66,87.82,17.30,156.70,29.87,808.46,1021.39,212.93,159.81,1077.81,12.22, 400459.06,1.05,344.19,87.82,17.30,156.70,29.87,808.96,1021.91,212.95,159.81,1077.29,12.22,
Total（1010.75） = TrackedTotal（800.97） + Untracked（209.78）
TrackedTotal（800.97） = Untagged（1.05） + FMalloc（333.55） + Metal Textures（87.24） + Metal Buffers（17.3） + Metal Render Targets（156.7） + ProgramSize（29.87） + LLMOverhead（163.04） + MMIO（12.22）
以第1条采集的值为例（单位MB），说明各统计项含义：
Untagged // 未分类的内存，即分配内存时候不在 LLM_SCOPE 宏范围内
ELLMTag::Untagged（Default Tracker）： 35.32
ELLMTag::Untagged（Platform Tracker）： 0
LLMOverhead // LLM本身消耗的内存
（Default Tracker）： 无
ELLMTag::PlatformOverhead（Platform Tracker）: 119.64
TrackedTotal // 通过调用 LLM OnLowLevelAlloc/OnLowLevelFree 统计到的所有内存 即：LLM跟踪到的所有内存
ELLMTag::TrackedTotal（Default Tracker）：789.74
ELLMTag::PlatformTrackedTotal（Platform Tracker）：907.32
注：统计到的内存值ELLMTag::PlatformTrackedTotal比ELLMTag::TrackedTotal要大
Total // 总内存
ELLMTag::PlatformTotal（Platform Tracker）：962.2
从操作系统获得的实际内存，不从llm获得。在Android上为RSS，Resident Set Size 实际使用物理内存（包含共享库占用的内存）
在iOS上为Resident（Wired），物理内存，即常驻内存，含干净页（代码、文件）和dirty页。
ELLMTag::Total（Default Tracker）：842.68
PlatformTotal - LLMOverhead。即为上面的内存减去 LLM 本身消耗的内存，这个内存值可以认为是在不打开 LLM 功能下的进程内存值
Untracked // 未知的内存分配，即 LLM 无法追踪的内存，比如第三方库里的内存分配
ELLMTag::PlatformUntracked（Platform Tracker）： 54.88 // PlatformTotal - PlatformTrackedTotal
ELLMTag::Untracked（Default Tracker）：52.88 // Total - TrackedTotal
FMalloc // 通过FMemory内存分配器分配的内存，也就是一般意义上引擎分配的内存，比如各种UObject，纹理，动画等占用的内存
（Default Tracker）： 无
ELLMTag::FMalloc（Platform Tracker）: 511.61
FMallocUnused // ELLMTag::FMalloc内存分配器的内存 - 通过FMemory得到的内存。即内存分配器中未使用的内存
ELLMTag::FMallocUnused（Default Tracker）： 56.45
（Platform Tracker）: 无
注：LLM追踪的内存有2种ELLMAllocType::FMalloc和ELLMAllocType::System
ProgramSize // 程序刚起来时占用的内存（具体时机是初始化某个static FName变量，在进入main函数之前），用来弥补LLM初始化之前没有跟踪到的部分
ELLMTag::ProgramSize（Default Tracker）：157.18
ELLMTag::ProgramSizePlatform（Platform Tracker）：157.18
Graphics // 显存
（Default Tracker）： 无
ELLMTag::GraphicsPlatform（Platform Tracker）: 115.27
GenericPlatformMallocCrash // 预分配的 crash 相关的内存，当 crash 发生时用来替换GMalloc
ELLMTag::GenericPlatformMallocCrash（Default Tracker）：3.61
ELLMTag::GenericPlatformMallocCrashPlatform（Platform Tracker）：3.61
OSAvailable // 系统当前可用的物理内存
（Default Tracker）： 无
ELLMTag::PlatformOSAvailable（Platform Tracker）: 3388.55
OOMBackupPool // Out of memory 备用内存池
ELLMTag::BackupOOMMemoryPool（Default Tracker）：未统计
ELLMTag::BackupOOMMemoryPoolPlatform（Platform Tracker）: 未统计
Default Tracker详细的统计项
ELLMTag::EngineMisc 3.78 // 在以下函数执行过程中分配的内存
AActor::ProcessEvent
UPackageMapClient::SerializeNewActor
FEngineLoop::Tick
ELLMTag::TaskGraphTasksMisc 0 // FTaskThreadAnyThread::ProcessTasks 函数执行过程中分配的内存
Audio 9.52 // 音频相关的内存，包括音频资源，音频线程中分配的内存，具体还包含以下子类别
ELLMTag::AudioMisc 0.02
ELLMTag::AudioSoundWaves
ELLMTag::AudioMixer 9.52
ELLMTag::AudioPrecache
ELLMTag::AudioDecompress
ELLMTag::AudioRealtimePrecache
ELLMTag::AudioFullDecompress
ELLMTag::AudioVoiceChat
ELLMTag::FName 7.12 // FName占用的内存
ELLMTag::Networking // 网络相关的内存，包含网络包处理，连接对象内存等
ELLMTag::Meshes 31.85 // Mesh 的顶点缓存，顶点索引缓存占用的内存，还有以下子类别 注：包括VertexBuffer相关在cpu这边的内存+估算的gpu内存
ELLMTag::StaticMesh 8.79 // StaticMesh 相关的内存，包含 StaticMesh 资源，StaticMeshComponent
ELLMTag::SkeletalMesh 12.33 // SkeletalMeshComponent, SkinnedMeshComponent, SkeletalMesh内存
ELLMTag::InstancedMesh 0.13 // InstancedStaticMeshComponent, HierarchicalInstancedStaticMeshComponent内存
ELLMTag::Landscape // LandscapeComponent, LandscapeProxy, LandscapeComponentSceneProxy内存
ELLMTag::Stats 21.65 // stat 统计相关的内存占用
ELLMTag::Shaders 19.11 // 各种类型 Shander 的内存占用
ELLMTag::PSO 0.15 // Pipeline State Object 缓存的内存占用
ELLMTag::Textures 67.28 // 纹理相关的内存占用 注：包括texture相关在cpu这边的内存+估算的gpu内存
ELLMTag::TextureMetaData 0.65 // UTexture2D::Serialize 函数执行过程中分配的内存
ELLMTag::RenderTargets 40.85 // RT 相关的内存，包含在 Viewport 中渲染使用的内存
ELLMTag::SceneRender 34.72 // 场景渲染相关的内存占用，包含 Slate RHI Render 的窗口渲染
ELLMTag::RHIMisc 0.8 // 其它渲染相关的内存占用，如各种渲染状态，RHI Thread 运行过程中的内存
ELLMTag::AsyncLoading 3.08 // 异步资源加载过程中的内存占用，包含 AsyncLoadingThread, Event Driven Loader
ELLMTag::UObject 105.19 // UObject 占用的内存，包含 UClass 等
ELLMTag::Animation 13.38 // 动画相关的内存，包含 AnimInstance, AnimSequence, AnimationAsset, AnimBlueprint, MorphTarget
ELLMTag::Materials 0.54 // 材质相关的内存，包含 MaterialInterface, MaterialFunction
ELLMTag::Particles 0.78 // 特效相关的内存，包含 ParticleSystemComponent
ELLMTag::GC 0.62 // GC 过程中的内存，分别为以下两个函数
CollectGarbageInternal
PerformReachabilityAnalysis
ELLMTag::UI 42.7 // Slate 相关的内存，包含字体，TextureAtlas 注：TextureAltas为slate内部的altas，不是TEXTGROUP为UI的贴图
ELLMTag::PhysX // PhysX 物理相关的内存
ELLMTag::EnginePreInitMemory 18.71 // FEngineLoop::PreInit 函数执行过程中的内存
ELLMTag::EngineInitMemory 0.9 // FEngineLoop::Init 函数执行过程中的内存
ELLMTag::RenderingThreadMemory 6.21 // 渲染线程(RenderingThreadMain)执行过程中的内存
ELLMTag::LoadMapMisc 5.05 // 地图加载过程中的内存，分别为以下两个函数
UEngine::LoadMap
UWorld::UpdateLevelStreaming
ELLMTag::StreamingManager 0.44 // StreamableManager 相关的内存，主要是资源 streaming 函数执行过程中的内存
ELLMTag::FileSystem 13.72 // 文件系统相关的内存，主要是文件读取时的缓冲区，比如Pak 文件
ELLMTag::Localization 36.59 // 本地化相关的内存
ELLMTag::AssetRegistry 0.13 // AssetRegistryModule 内存
ELLMTag::ConfigSystem 2.8 // 配置文件相关的内存
ELLMTag::InitUObject 12.84 // InitUObject函数执行过程中的内存
ELLMTag::MaterialInstance 0.31 // MaterialInstance, MaterialInstanceDynamic包括材质参数内存占用
ELLMTag::Lua 28.88 // Lua 内存
Windows下特有统计项
ELLMTag::WorkingSetSize // 进程物理内存，可用这个值替代上面的PlatformTotal
ELLMTag::PagefileUsed // 进程虚拟内存
ThreadStack // Windows 线程栈内存
ELLMTag::ThreadStack（Platform Tracker）
ELLMTag::ThreadStackPlatform（Default Tracker）
IOS下特有统计项
Metal Buffers
ELLMTagMetal::Buffers（Platform Tracker） 17.30
ELLMTagMetal::Buffers（Default Tracker） 0.12
Metal Textures
ELLMTagMetal::Textures（Platform Tracker）87.24
ELLMTagMetal::Textures（Default Tracker）0.1
Metal RenderTargets
ELLMTagMetal::RenderTargets（Platform Tracker）156.70
MMIO
ELLMTag::PlatformMMIO（Platform Tracker，mmap / munmap文件映射）12.22
llm stat控制台命令
stat llm // 显示 Default Tracker 分组的简要内存统计信息
stat llmfull // 显示 Default Tracker 分组的所有内存统计信息
注1：默认一个Group最多显示的行数为25，可通过执行控制台变量stats.MaxPerGroup xx来指定新的最大行数为xx
注2：为了能查看显示不下的内容，自定义开发了stat scroll控制台命令
stat scroll 1 // 向下滚动1行
stat scroll -1 // 向上滚动1行
stat scroll 999 // 滚动到底部
stat scroll -999 // 滚动到顶部
stat scroll restore //恢复初始
Stat LLMPlatform // 显示 Platform Tracker 分组的内存统计信息
Stat LLMOverhead // 显示 LLM 本身使用的内存信息
新增统计项标签
可以通过以下方式新增一个ELLMTag::ANR的统计项标签
/*** UnrealEngine\Engine\Source\Runtime\Core\Public\HAL\LowLevelMemTracker.h ***/ #define LLM_ENUM_GENERIC_TAGS(macro) \ // 枚举名 用于显示的名称 显示在stat llmfull命令的输出结果中 显示在stat llm命令的输出结果中 父llm类别 macro(Untagged, "Untagged", NAME_None, NAME_None, -1)\ //0 macro(Paused, "Paused", NAME_None, NAME_None, -1)\ //1 macro(Total, "Total", GET_STATFNAME(STAT_TotalLLM), GET_STATFNAME(STAT_TrackedTotalSummaryLLM), -1)\ //2 macro(Untracked, "Untracked", GET_STATFNAME(STAT_UntrackedLLM), GET_STATFNAME(STAT_TrackedTotalSummaryLLM), -1)\ //3 macro(PlatformTotal, "Total", GET_STATFNAME(STAT_PlatformTotalLLM), NAME_None, -1)\ //4 macro(TrackedTotal, "TrackedTotal", GET_STATFNAME(STAT_TrackedTotalLLM), GET_STATFNAME(STAT_TrackedTotalSummaryLLM), -1)\ //5 macro(UntaggedTotal, "Untagged", GET_STATFNAME(STAT_UntaggedTotalLLM), NAME_None, -1)\ //6 macro(WorkingSetSize, "WorkingSetSize", GET_STATFNAME(STAT_WorkingSetSizeLLM), GET_STATFNAME(STAT_TrackedTotalSummaryLLM), -1)\ //7 macro(PagefileUsed, "PagefileUsed", GET_STATFNAME(STAT_PagefileUsedLLM), GET_STATFNAME(STAT_TrackedTotalSummaryLLM), -1)\ //8 macro(PlatformTrackedTotal, "TrackedTotal", GET_STATFNAME(STAT_PlatformTrackedTotalLLM), NAME_None, -1)\ //9 macro(PlatformUntaggedTotal, "Untagged", GET_STATFNAME(STAT_PlatformUntaggedTotalLLM), NAME_None, -1)\ //10 macro(PlatformUntracked, "Untracked", GET_STATFNAME(STAT_PlatformUntrackedLLM), NAME_None, -1)\ //11 macro(PlatformOverhead, "LLMOverhead", GET_STATFNAME(STAT_PlatformOverheadLLM), NAME_None, -1)\ //12 macro(PlatformOSAvailable, "OSAvailable", GET_STATFNAME(STAT_PlatformOSAvailableLLM), NAME_None, -1)\ //13 macro(FMalloc, "FMalloc", GET_STATFNAME(STAT_FMallocLLM), NAME_None, -1)\ //14 macro(FMallocUnused, "FMallocUnused", GET_STATFNAME(STAT_FMallocUnusedLLM), GET_STATFNAME(STAT_EngineSummaryLLM), -1)\ //15 macro(ThreadStack, "ThreadStack", GET_STATFNAME(STAT_ThreadStackLLM), GET_STATFNAME(STAT_EngineSummaryLLM), -1)\ //16 macro(ThreadStackPlatform, "ThreadStack", GET_STATFNAME(STAT_ThreadStackPlatformLLM), NAME_None, -1)\ //17 macro(ProgramSizePlatform, "ProgramSize", GET_STATFNAME(STAT_ProgramSizePlatformLLM), NAME_None, -1)\ //18 macro(ProgramSize, "ProgramSize", GET_STATFNAME(STAT_ProgramSizeLLM), GET_STATFNAME(STAT_EngineSummaryLLM), -1)\ //19 macro(BackupOOMMemoryPoolPlatform, "OOMBackupPool", GET_STATFNAME(STAT_OOMBackupPoolPlatformLLM), NAME_None, -1)\ //20 macro(BackupOOMMemoryPool, "OOMBackupPool", GET_STATFNAME(STAT_OOMBackupPoolLLM), GET_STATFNAME(STAT_EngineSummaryLLM), -1)\ //21 macro(GenericPlatformMallocCrash, "GenericPlatformMallocCrash", GET_STATFNAME(STAT_GenericPlatformMallocCrashLLM), GET_STATFNAME(STAT_EngineSummaryLLM), -1)\ //22 macro(GenericPlatformMallocCrashPlatform, "GenericPlatformMallocCrash", GET_STATFNAME(STAT_GenericPlatformMallocCrashPlatformLLM), GET_STATFNAME(STAT_EngineSummaryLLM), -1)\ //23 macro(EngineMisc, "EngineMisc", GET_STATFNAME(STAT_EngineMiscLLM), GET_STATFNAME(STAT_EngineSummaryLLM), -1)\ //24 macro(TaskGraphTasksMisc, "TaskGraphMiscTasks", GET_STATFNAME(STAT_TaskGraphTasksMiscLLM), GET_STATFNAME(STAT_EngineSummaryLLM), -1)\ //25 macro(Audio, "Audio", GET_STATFNAME(STAT_AudioLLM), GET_STATFNAME(STAT_AudioSummaryLLM), -1)\ //26 macro(AudioMisc, "AudioMisc", GET_STATFNAME(STAT_AudioMiscLLM), GET_STATFNAME(STAT_AudioSummaryLLM), ELLMTag::Audio)\ //27 macro(AudioSoundWaves, "AudioSoundWaves", GET_STATFNAME(STAT_AudioSoundWavesLLM), GET_STATFNAME(STAT_AudioSummaryLLM), ELLMTag::Audio)\ //28 macro(AudioMixer, "AudioMixer", GET_STATFNAME(STAT_AudioMixerLLM), GET_STATFNAME(STAT_AudioSummaryLLM), ELLMTag::Audio)\ //29 macro(AudioMixerPlugins, "AudioMixerPlugins", GET_STATFNAME(STAT_AudioMixerPluginsLLM), GET_STATFNAME(STAT_AudioSummaryLLM), ELLMTag::Audio)\ //30 macro(AudioPrecache, "AudioPrecache", GET_STATFNAME(STAT_AudioPrecacheLLM), GET_STATFNAME(STAT_AudioSummaryLLM), ELLMTag::Audio)\ //31 macro(AudioDecompress, "AudioDecompress", GET_STATFNAME(STAT_AudioDecompressLLM), GET_STATFNAME(STAT_AudioSummaryLLM), ELLMTag::Audio)\ //32 macro(AudioRealtimePrecache, "AudioRealtimePrecache", GET_STATFNAME(STAT_AudioRealtimePrecacheLLM), GET_STATFNAME(STAT_AudioSummaryLLM), ELLMTag::Audio)\ //33 macro(AudioFullDecompress, "AudioFullDecompress", GET_STATFNAME(STAT_AudioFullDecompressLLM), GET_STATFNAME(STAT_AudioSummaryLLM), ELLMTag::Audio)\ //34 macro(AudioVoiceChat, "AudioVoiceChat", GET_STATFNAME(STAT_AudioVoiceChatLLM), GET_STATFNAME(STAT_AudioSummaryLLM), ELLMTag::Audio)\ //35 macro(AudioStreamCache, "AudioStreamCache", GET_STATFNAME(STAT_AudioStreamCacheLLM), GET_STATFNAME(STAT_AudioSummaryLLM), ELLMTag::Audio)\ //36 macro(AudioStreamCacheCompressedData, "AudioStreamCacheCompressedData",GET_STATFNAME(STAT_AudioStreamCacheCompressedDataLLM), GET_STATFNAME(STAT_AudioSummaryLLM), ELLMTag::Audio)\ //37 macro(AudioSynthesis, "AudioSynthesis", GET_STATFNAME(STAT_AudioSynthesisLLM), GET_STATFNAME(STAT_AudioSummaryLLM), ELLMTag::Audio)\ //38 macro(FName, "FName", GET_STATFNAME(STAT_FNameLLM), GET_STATFNAME(STAT_EngineSummaryLLM), -1)\ //39 macro(Networking, "Networking", GET_STATFNAME(STAT_NetworkingLLM), GET_STATFNAME(STAT_EngineSummaryLLM), -1)\ //40 macro(Meshes, "Meshes", GET_STATFNAME(STAT_MeshesLLM), GET_STATFNAME(STAT_MeshesSummaryLLM), -1)\ //41 macro(Stats, "Stats", GET_STATFNAME(STAT_StatsLLM), GET_STATFNAME(STAT_EngineSummaryLLM), -1)\ //42 macro(Shaders, "Shaders", GET_STATFNAME(STAT_ShadersLLM), GET_STATFNAME(STAT_EngineSummaryLLM), -1)\ //43 macro(PSO, "PSO", GET_STATFNAME(STAT_PSOLLM), GET_STATFNAME(STAT_EngineSummaryLLM), -1)\ //44 macro(Textures, "Textures", GET_STATFNAME(STAT_TexturesLLM), GET_STATFNAME(STAT_TexturesSummaryLLM), -1)\ //45 macro(TextureMetaData, "TextureMetaData", GET_STATFNAME(STAT_TextureMetaDataLLM), GET_STATFNAME(STAT_TexturesSummaryLLM), -1)\ //46 macro(VirtualTextureSystem, "VirtualTextureSystem", GET_STATFNAME(STAT_VirtualTextureSystemLLM), GET_STATFNAME(STAT_TexturesSummaryLLM), -1)\ //47 macro(RenderTargets, "RenderTargets", GET_STATFNAME(STAT_RenderTargetsLLM), GET_STATFNAME(STAT_EngineSummaryLLM), -1)\ //48 macro(SceneRender, "SceneRender", GET_STATFNAME(STAT_SceneRenderLLM), GET_STATFNAME(STAT_EngineSummaryLLM), -1)\ //49 macro(RHIMisc, "RHIMisc", GET_STATFNAME(STAT_RHIMiscLLM), GET_STATFNAME(STAT_EngineSummaryLLM), -1)\ //50 macro(AsyncLoading, "AsyncLoading", GET_STATFNAME(STAT_AsyncLoadingLLM), GET_STATFNAME(STAT_EngineSummaryLLM), -1)\ //51 macro(UObject, "UObject", GET_STATFNAME(STAT_UObjectLLM), GET_STATFNAME(STAT_UObjectSummaryLLM), -1)\ //52 macro(Animation, "Animation", GET_STATFNAME(STAT_AnimationLLM), GET_STATFNAME(STAT_AnimationSummaryLLM), -1)\ //53 macro(StaticMesh, "StaticMesh", GET_STATFNAME(STAT_StaticMeshLLM), GET_STATFNAME(STAT_StaticMeshSummaryLLM), ELLMTag::Meshes)\ //54 macro(Materials, "Materials", GET_STATFNAME(STAT_MaterialsLLM), GET_STATFNAME(STAT_MaterialsSummaryLLM), -1)\ //55 macro(Particles, "Particles", GET_STATFNAME(STAT_ParticlesLLM), GET_STATFNAME(STAT_ParticlesSummaryLLM), -1)\ //56 macro(Niagara, "Niagara", GET_STATFNAME(STAT_NiagaraLLM), GET_STATFNAME(STAT_NiagaraSummaryLLM), -1)\ //57 macro(GPUSort, "GPUSort", GET_STATFNAME(STAT_GPUSortLLM), GET_STATFNAME(STAT_EngineSummaryLLM), -1)\ //58 macro(GC, "GC", GET_STATFNAME(STAT_GCLLM), GET_STATFNAME(STAT_EngineSummaryLLM), -1)\ //59 macro(UI, "UI", GET_STATFNAME(STAT_UILLM), GET_STATFNAME(STAT_UISummaryLLM), -1)\ //60 macro(NavigationRecast, "NavigationRecast", GET_STATFNAME(STAT_NavigationRecastLLM), GET_STATFNAME(STAT_NavigationSummaryLLM), -1)\ //61 macro(Physics, "Physics", GET_STATFNAME(STAT_PhysicsLLM), GET_STATFNAME(STAT_PhysicsSummaryLLM), -1)\ //62 macro(PhysX, "PhysX", GET_STATFNAME(STAT_PhysXLLM), GET_STATFNAME(STAT_PhysXSummaryLLM), ELLMTag::Physics)\ //63 macro(PhysXGeometry, "PhysXGeometry", GET_STATFNAME(STAT_PhysXGeometryLLM), GET_STATFNAME(STAT_PhysXSummaryLLM), ELLMTag::Physics)\ //64 macro(PhysXTrimesh, "PhysXTrimesh", GET_STATFNAME(STAT_PhysXTrimeshLLM), GET_STATFNAME(STAT_PhysXSummaryLLM), ELLMTag::Physics)\ //65 macro(PhysXConvex, "PhysXConvex", GET_STATFNAME(STAT_PhysXConvexLLM), GET_STATFNAME(STAT_PhysXSummaryLLM), ELLMTag::Physics)\ //66 macro(PhysXAllocator, "PhysXAllocator", GET_STATFNAME(STAT_PhysXAllocatorLLM), GET_STATFNAME(STAT_PhysXSummaryLLM), ELLMTag::Physics)\ //67 macro(PhysXLandscape, "PhysXLandscape", GET_STATFNAME(STAT_PhysXLandscapeLLM), GET_STATFNAME(STAT_PhysXSummaryLLM), ELLMTag::Physics)\ //68 macro(Chaos, "Chaos", GET_STATFNAME(STAT_ChaosLLM), GET_STATFNAME(STAT_ChaosSummaryLLM), ELLMTag::Physics)\ //69 macro(ChaosGeometry, "ChaosGeometry", GET_STATFNAME(STAT_ChaosGeometryLLM), GET_STATFNAME(STAT_ChaosSummaryLLM), ELLMTag::Physics)\ //70 macro(ChaosAcceleration, "ChaosAcceleration", GET_STATFNAME(STAT_ChaosAccelerationLLM), GET_STATFNAME(STAT_ChaosSummaryLLM), ELLMTag::Physics)\ //71 macro(ChaosParticles, "ChaosParticles", GET_STATFNAME(STAT_ChaosParticlesLLM), GET_STATFNAME(STAT_ChaosSummaryLLM), ELLMTag::Physics)\ //72 macro(ChaosLandscape, "ChaosLandscape", GET_STATFNAME(STAT_ChaosLandscapeLLM), GET_STATFNAME(STAT_ChaosSummaryLLM), ELLMTag::Physics)\ //73 macro(ChaosTrimesh, "ChaosTrimesh", GET_STATFNAME(STAT_ChaosTrimeshLLM), GET_STATFNAME(STAT_ChaosSummaryLLM), ELLMTag::Physics)\ //74 macro(ChaosConvex, "ChaosConvex", GET_STATFNAME(STAT_ChaosConvexLLM), GET_STATFNAME(STAT_ChaosSummaryLLM), ELLMTag::Physics)\ //75 macro(EnginePreInitMemory, "EnginePreInit", GET_STATFNAME(STAT_EnginePreInitLLM), GET_STATFNAME(STAT_EngineSummaryLLM), -1)\ //76 macro(EngineInitMemory, "EngineInit", GET_STATFNAME(STAT_EngineInitLLM), GET_STATFNAME(STAT_EngineSummaryLLM), -1)\ //77 macro(RenderingThreadMemory, "RenderingThread", GET_STATFNAME(STAT_RenderingThreadLLM), GET_STATFNAME(STAT_EngineSummaryLLM), -1)\ //78 macro(LoadMapMisc, "LoadMapMisc", GET_STATFNAME(STAT_LoadMapMiscLLM), GET_STATFNAME(STAT_EngineSummaryLLM), -1)\ //79 macro(StreamingManager, "StreamingManager", GET_STATFNAME(STAT_StreamingManagerLLM), GET_STATFNAME(STAT_EngineSummaryLLM), -1)\ //80 macro(GraphicsPlatform, "Graphics", GET_STATFNAME(STAT_GraphicsPlatformLLM), NAME_None, -1)\ //81 macro(FileSystem, "FileSystem", GET_STATFNAME(STAT_FileSystemLLM), GET_STATFNAME(STAT_EngineSummaryLLM), -1)\ //82 macro(Localization, "Localization", GET_STATFNAME(STAT_LocalizationLLM), GET_STATFNAME(STAT_EngineSummaryLLM), -1)\ //83 macro(AssetRegistry, "AssetRegistry", GET_STATFNAME(STAT_AssetRegistryLLM), GET_STATFNAME(STAT_EngineSummaryLLM), -1)\ //84 macro(ConfigSystem, "ConfigSystem", GET_STATFNAME(STAT_ConfigSystemLLM), GET_STATFNAME(STAT_EngineSummaryLLM), -1)\ //85 macro(InitUObject, "InitUObject", GET_STATFNAME(STAT_InitUObjectLLM), GET_STATFNAME(STAT_EngineSummaryLLM), -1)\ //86 macro(VideoRecording, "VideoRecording", GET_STATFNAME(STAT_VideoRecordingLLM), GET_STATFNAME(STAT_EngineSummaryLLM), -1)\ //87 macro(Replays, "Replays", GET_STATFNAME(STAT_ReplaysLLM), GET_STATFNAME(STAT_EngineSummaryLLM), -1)\ //88 macro(MaterialInstance, "MaterialInstance", GET_STATFNAME(STAT_MaterialInstanceLLM), GET_STATFNAME(STAT_EngineSummaryLLM), -1)\ //89 macro(SkeletalMesh, "SkeletalMesh", GET_STATFNAME(STAT_SkeletalMeshLLM), GET_STATFNAME(STAT_EngineSummaryLLM), ELLMTag::Meshes)\ //90 macro(InstancedMesh, "InstancedMesh", GET_STATFNAME(STAT_InstancedMeshLLM), GET_STATFNAME(STAT_EngineSummaryLLM), ELLMTag::Meshes)\ //91 macro(Landscape, "Landscape", GET_STATFNAME(STAT_LandscapeLLM), GET_STATFNAME(STAT_EngineSummaryLLM), ELLMTag::Meshes)\ //92 macro(CsvProfiler, "CsvProfiler", GET_STATFNAME(STAT_CsvProfilerLLM), GET_STATFNAME(STAT_EngineSummaryLLM), -1)\ // 93 macro(MediaStreaming, "MediaStreaming", GET_STATFNAME(STAT_MediaStreamingLLM), GET_STATFNAME(STAT_MediaStreamingSummaryLLM), -1)\ // 94 macro(ElectraPlayer, "ElectraPlayer", GET_STATFNAME(STAT_ElectraPlayerLLM), GET_STATFNAME(STAT_MediaStreamingSummaryLLM), ELLMTag::MediaStreaming)\ // 95 macro(WMFPlayer, "WMFPlayer", GET_STATFNAME(STAT_WMFPlayerLLM), GET_STATFNAME(STAT_MediaStreamingSummaryLLM), ELLMTag::MediaStreaming)\ // 96 macro(PlatformMMIO, "MMIO", GET_STATFNAME(STAT_PlatformMMIOLLM), NAME_None, -1)\ // 97 macro(PlatformVM, "Virtual Memory", GET_STATFNAME(STAT_PlatformVMLLM), NAME_None, -1)\ // 98 macro(Lua, "Lua", GET_STATFNAME(STAT_LuaLLM), GET_STATFNAME(STAT_LuaSummaryLLM), -1)\ // 99 macro(Font, "Font", GET_STATFNAME(STAT_FontLLM), NAME_None, ELLMTag::UI)\ // 100 macro(Wwise, "Wwise", GET_STATFNAME(STAT_WwiseLLM), NAME_None, -1)\ // 101 macro(GCloud, "GCloud", GET_STATFNAME(STAT_GCloudLLM), NAME_None, -1)\ // 102 macro(MergeTexture, "MergeTexture", GET_STATFNAME(STAT_MergeTextureLLM), GET_STATFNAME(STAT_TexturesSummaryLLM), ELLMTag::Textures)\ // 103 macro(SlateGenerateByClass, "SlateGenerateByClass", GET_STATFNAME(STAT_SlateGenerateByClassLLM), NAME_None, ELLMTag::UI)\ // 104 /* 自定义一个llm分类标签 */ macro(ANR, "Application Not Respond", GET_STATFNAME(STAT_ANRLLM), GET_STATFNAME(STAT_ANRSummaryLLM), -1)\ // 105 macro(MemoryTestType, "MemoryTestType", NAME_None, NAME_None, -1)\ macro(MemoryTestSubType, "MemoryTestSubType", NAME_None, NAME_None, ELLMTag::MemoryTestType)\ /*** UnrealEngine\Engine\Source\Runtime\Core\Private\HAL\LowLevelMemTracker.cpp ***/ DECLARE_LLM_MEMORY_STAT(TEXT("ANR"), STAT_ANRLLM, STATGROUP_LLMFULL); // ANR显示在stat llmfull的统计中 注：这个STAT分类定义不是必须的 DECLARE_LLM_MEMORY_STAT(TEXT("ANR"), STAT_ANRSummaryLLM, STATGROUP_LLM); // ANR显示在stat llm的统计中 注：这个STAT分类定义不是必须的 /*** 统计 LLMPlatform_Pid100956_2022.03.28-17.52.11.csv ***/ { LLM_PLATFORM_SCOPE(ELLMTag::ANR); // Do Something } /*** LLM_Pid100956_2022.03.28-17.52.11.csv ***/ { LLM_SCOPE(ELLMTag::ANR); // Do Something }
嵌套统计：
LLM_SCOPE(ELLMTag::ANR); // 统计ANR作用域范围内的独占内存（Exclusive）：2MB + 5 MB = 7MB int8* p1 = new int8[2*1024*1024]; // 2MB { LLM_SCOPE(ELLMTag::MemoryTestType); // 统计MemoryTestType作用域范围内的独占内存（Exclusive）：3MB int8* p2 = new int8[3*1024*1024]; // 3MB } int8* p3 = new int8[5 * 1024 * 1024]; // 5MB
子分类统计：上面的示例代码中，MemoryTestSubType是MemoryTestType的子分类，当执行LLM_SCOPE(ELLMTag::MemoryTestSubType)统计时，ELLMTag::MemoryTestType会自动进行统计累加。
如果要将ANR的统计写入csv文件，需要在开始写csv文件之前，触发LLM_SCOPE(ELLMTag::ANR)一次，且在其作用域内触发堆内存分配。
/*** LLM_Pid100956_2022.03.28-17.52.11.csv ***/ { LLM_SCOPE(ELLMTag::ANR); TUniquePtr<int32> up1(new int32(5)); // 内部会触发堆内存分配 // Do Something }
LLM_SCOPE(InheritedLLMTag)
使用当前ActiveTag来统计。在AsyncWork.h、TaskGraphInterfaces.h中有使用到该动态Tag。
以TaskGraphInterfaces为例，具体实现方式是在构造Task任务时，获取当前ActiveTag来动态设置InheritedLLMTag的值
FBaseGraphTask(int32 InNumberOfPrerequistitesOutstanding) : ThreadToExecuteOn(ENamedThreads::AnyThread) , NumberOfPrerequistitesOutstanding(InNumberOfPrerequistitesOutstanding + 1) // + 1 is not a prerequisite, it is a lock to prevent it from executing while it is getting prerequisites, one it is safe to execute, call PrerequisitesComplete { checkThreadGraph(LifeStage.Increment() == int32(LS_Contructed)); LLM(InheritedLLMTag = FLowLevelMemTracker::bIsDisabled ? ELLMTag::Untagged : (ELLMTag)FLowLevelMemTracker::Get().GetActiveTag(ELLMTracker::Default)); }
设置后，就可以在相应逻辑中使用该Tag进行内存统计
放置LLM_SCOPE的函数如果发生了内联，统计分类将放到调用处的函数中
如UnrealEngine\Engine\Source\Runtime\Core\Public\Async\TaskGraphInterfaces.h文件中的FBaseGraphTask.Execute函数
FORCEINLINE void Execute(TArray<FBaseGraphTask*>& NewTasks, ENamedThreads::Type CurrentThread) { LLM_SCOPE(InheritedLLMTag); checkThreadGraph(LifeStage.Increment() == int32(LS_Executing)); ExecuteTask(NewTasks, CurrentThread); }
导致在非Debug包下，在堆栈中看不到这个函数名：
0x000000748C7CB524 libUE4.so(0x0000000014747524)!FLLMScope::FLLMScope(ELLMTag, ELLMTagSet, ELLMTracker) [] 0x000000748C6EBECC libUE4.so(0x0000000014667ECC)!FNamedTaskThread::ProcessTasksNamedThread(int, bool) [] // FBaseGraphTask.Execute函数被inline到了FNamedTaskThread::ProcessTasksNamedThread函数中了 0x000000748C6E8DFC libUE4.so(0x0000000014664DFC)!FNamedTaskThread::ProcessTasksUntilQuit(int) [] 0x000000748DF66740 libUE4.so(0x0000000015EE2740)!FRHIThread::Run() [] 0x000000748C81D65C libUE4.so(0x000000001479965C)!FRunnableThreadPThread::Run() [] 0x000000748C6E2940 libUE4.so(0x000000001465E940)!FRunnableThreadPThread::_ThreadProc(void*) [] 0x000000759D609868 libc.so(0x00000000000EB868)![Unknown]() [] 0x000000759D5A9A88 libc.so(0x000000000008BA88)![Unknown]() []
在Debug包中，则能看到FBaseGraphTask.Execute函数的栈帧：
引擎写csv文件的时机
打印某类tag的内存分配Stack
如下：在FLLMTracker::TrackAllocation函数中，打印DefaultTriacker所有Untaged标签的线程栈到log文件
static bool GIsStackDumping = false; // 防止在Dump的过程中，分配内存被TrackAllocation，造成死循环 void FLLMTracker::TrackAllocation(const void* Ptr, uint64 Size, ELLMTag DefaultTag, ELLMTracker Tracker, ELLMAllocType AllocType, bool bTrackInMemPro) { if (IsPaused(AllocType)) { return; } // track the total quickly FPlatformAtomics::InterlockedAdd(&TrackedMemoryOverFrames, (int64)Size); FLLMThreadState* State = GetOrCreateState(); // track on the thread state, and get the tag State->TrackAllocation(Ptr, Size, DefaultTag, Tracker, AllocType, bTrackInMemPro); // tracking a nullptr with a Size is allowed, but we don't need to remember it, since we can't free it ever if (Ptr != nullptr) { // remember the size and tag info int64 Tag = State->GetTopTag(); if (Tag == (int64)ELLMTag::Untagged) { Tag = (int64)DefaultTag; } // 打印DefaultTriacker所有Untaged标签的线程栈到log文件 if (Tag == (int64)ELLMTag::Untagged && Tracker == ELLMTracker::Default) { #if PLATFORM_ANDROID static bool bDumpStack = (access("/storage/emulated/0/UE4Game/dumpstack.txt", 0) == 0); #elif PLATFORM_IOS NSString* DocumentsPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0]; NSString* FlagFilePath = [DocumentsPath stringByAppendingPathComponent : @"/dumpstack.txt"]; static bool bDumpStack = (access([FlagFilePath UTF8String], 0) == 0); #else static bool bDumpStack = false; #endif if (bDumpStack && !GIsStackDumping) { GIsStackDumping = true; UE_LOG(LogTemp, Display, TEXT("Track Size: %lld"), Size); FDebug::DumpStackTraceToLog(ELogVerbosity::Display); GIsStackDumping = false; } } FLLMTracker::FLowLevelAllocInfo AllocInfo; #if LLM_USE_ALLOC_INFO_STRUCT AllocInfo.Tag = Tag; #if LLM_ALLOW_ASSETS_TAGS AllocInfo.AssetTag = State->GetTopAssetTag(); #endif #else LLMCheck(Tag >= 0 && Tag < (int64)LLM_TAG_COUNT); AllocInfo = (ELLMTag)Tag; #endif LLMCheck(Size <= 0xffffffffu); GetAllocationMap().Add(Ptr, (uint32)Size, AllocInfo); } }
参考
UE4 Low Level Memory Tracker 使用（知乎）
UE4 Low Level Memory Tracker 使用
