Add EventPipe tracing support

Documentation/guides/tracing.md

@@ -0,0 +1,93 @@
+# Using a device connected via USB
+
+## Startup profiling
+### Set up reverse port forwarding:
+```
+$ adb reverse tcp:9000 tcp:9001
+```
+This will forward port 9000 on device to port 9001. Alternatively:
+```
+$ adb reverse tcp:0 tcp:9001
+43399
+```
+This will allocate a random port on remote and forward it to port 9001 on the host. The forwarded port is printed by adb
+
+### Configure the device so that the profiled app suspends until tracing utility connects
+
+```
+$ adb shell setprop debug.mono.profile '127.0.0.1:9000,suspend'
+```
+
+### Start the tracing router/proxy on host
+We assume ports as given above, in the first example.
+```
+$ dotnet-dsrouter client-server -tcps 127.0.0.1:9001 -ipcc /tmp/maui-app --verbose debug
+WARNING: dotnet-dsrouter is an experimental development tool not intended for production environments.
+
+info: dotnet-dsrounter[0]
+      Starting IPC client (/tmp/maui-app) <--> TCP server (127.0.0.1:9001) router.
+dbug: dotnet-dsrounter[0]
+      Trying to create a new router instance.
+dbug: dotnet-dsrounter[0]
+      Waiting for a new tcp connection at endpoint "127.0.0.1:9001".
+```
+
+This starts a `dsrouter` TCP/IP server on host port `9000` and an IPC (Unix socket on *nix machines) client with the socket name/path `/tmp/maui-app`
+
+### Start the tracing client
+
+Before starting the client make sure that the socket file does **not** exist.
+
+```
+$ dotnet-trace collect --diagnostic-port /tmp/maui-app --format speedscope -o /tmp/hellomaui-app-trace
+No profile or providers specified, defaulting to trace profile 'cpu-sampling'
+
+Provider Name                           Keywords            Level               Enabled By
+Microsoft-DotNETCore-SampleProfiler     0x0000F00000000000  Informational(4)    --profile 
+Microsoft-Windows-DotNETRuntime         0x00000014C14FCCBD  Informational(4)    --profile 
+
+Waiting for connection on /tmp/maui-app
+Start an application with the following environment variable: DOTNET_DiagnosticPorts=/tmp/maui-app
+```
+
+The `--format` argument is optional and it defaults to `nettrace`. However, `nettrace` files can be viewed only with
+Perfview on Windows, while the speedscope JSON files can be viewed "on" Unix by uploading them to https://speedscope.app
+
+### Compile and run the application
+
+```
+$ dotnet build -f net6.0-android \
+        /t:Install \
+        /bl \
+        /p:Configuration=Release \
+        /p:AndroidLinkResources=true \
+        /p:AndroidEnableProfiler=true
+```
+
+Once the application is installed and started, `dotnet-trace` should show something similar to:
+
+```
+Process        : $HOME/.dotnet/tools/dotnet-dsrouter
+Output File    : /tmp/hellomaui-app-trace
+[00:00:00:35]	Recording trace 1.7997   (MB)
+Press <Enter> or <Ctrl+C> to exit...812  (KB)
+```
+
+Once `<Enter>` is pressed, you should see:
+
+```
+Stopping the trace. This may take up to minutes depending on the application being traced.
+
+Trace completed.
+Writing:	/tmp/hellomaui-app-trace.speedscope.json
+```
+
+And the following files should be found in `/tmp`:
+
+```
+$ ls -h /tmp/hellomaui-app*|cat
+/tmp/hellomaui-app-trace
+/tmp/hellomaui-app-trace.speedscope.json
+```
+
+`/tmp/hellomaui-app-trace` is the nettrace file.

src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.AssemblyResolution.targets

@@ -168,8 +168,13 @@ _ResolveAssemblies MSBuild target.
     <ItemGroup>
       <_ResolvedNativeLibraries Include="@(ResolvedFileToPublish)" Condition=" '%(ResolvedFileToPublish.Extension)' == '.so' " />
     </ItemGroup>
+    <ItemGroup>
+      <_MonoComponent Condition=" '$(AndroidEnableProfiler)' == 'true' " Include="diagnostics_tracing" />
+      <_MonoComponent Condition=" '$(AndroidUseInterpreter)' == 'true' " Include="hot_reload" />
+    </ItemGroup>
     <ProcessNativeLibraries
         InputLibraries="@(_ResolvedNativeLibraries)"
+        Components="@(_MonoComponent->Distinct())"
         IncludeDebugSymbols="$(AndroidIncludeDebugSymbols)">
       <Output TaskParameter="OutputLibraries" ItemName="FrameworkNativeLibrary" />
     </ProcessNativeLibraries>

src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.DefaultProperties.targets

@@ -25,6 +25,9 @@
     -->
     <_GetChildProjectCopyToPublishDirectoryItems>false</_GetChildProjectCopyToPublishDirectoryItems>
     <UseMonoRuntime Condition=" '$(UseMonoRuntime)' == '' ">true</UseMonoRuntime>
+
+    <!-- Mono components -->
+    <AndroidEnableProfiler Condition=" '$(AndroidEnableProfiler)' == ''">false</AndroidEnableProfiler>
   </PropertyGroup>
 
   <!--  User-facing configuration-specific defaults -->
@@ -82,6 +85,8 @@
     <!-- XA feature switches defaults -->
     <VSAndroidDesigner Condition="'$(VSAndroidDesigner)' == ''">false</VSAndroidDesigner>
 
+    <!-- profiler won't work without internet permission, we must thus force it -->
+    <AndroidNeedsInternetPermission Condition=" '$(AndroidEnableProfiler)' == 'true' ">True</AndroidNeedsInternetPermission>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(AndroidApplication)' == 'true' and '$(GenerateApplicationManifest)' == 'true' ">
     <ApplicationVersion Condition=" '$(ApplicationVersion)' == '' ">1.0</ApplicationVersion>

src/Xamarin.Android.Build.Tasks/Tasks/ProcessNativeLibraries.cs

@@ -13,19 +13,19 @@ namespace Xamarin.Android.Tasks
 	/// </summary>
 	public class ProcessNativeLibraries : AndroidTask
 	{
+		const string MonoComponentPrefix = "libmono-component-";
+
 		public override string TaskPrefix => "PRNL";
 
-		static readonly HashSet<string> DebugNativeLibraries = new HashSet<string> {
+		static readonly HashSet<string> DebugNativeLibraries = new HashSet<string> (StringComparer.OrdinalIgnoreCase) {
 			"libxamarin-debug-app-helper",
-			// TODO: eventually we should have a proper mechanism for including/excluding Mono components
-			"libmono-component-diagnostics_tracing",
-			"libmono-component-hot_reload",
 		};
 
 		/// <summary>
 		/// Assumed to be .so files only
 		/// </summary>
 		public ITaskItem [] InputLibraries { get; set; }
+		public ITaskItem [] Components { get; set; }
 
 		public bool IncludeDebugSymbols { get; set; }
 
@@ -37,6 +37,13 @@ public override bool RunTask ()
 			if (InputLibraries == null || InputLibraries.Length == 0)
 				return true;
 
+			var wantedComponents = new HashSet<string> (StringComparer.OrdinalIgnoreCase);
+			if (Components != null && Components.Length > 0) {
+				foreach (ITaskItem item in Components) { ;
+					wantedComponents.Add ($"{MonoComponentPrefix}{item.ItemSpec}");
+				}
+			}
+
 			var output = new List<ITaskItem> (InputLibraries.Length);
 
 			foreach (var library in InputLibraries) {
@@ -69,7 +76,12 @@ public override bool RunTask ()
 						Log.LogDebugMessage ($"Excluding '{library.ItemSpec}' for release builds.");
 						continue;
 					}
+				} else if (fileName.StartsWith (MonoComponentPrefix, StringComparison.OrdinalIgnoreCase)) {
+					if (!wantedComponents.Contains (fileName)) {
+						continue;
+					}
 				}
+
 				output.Add (library);
 			}
 

src/monodroid/jni/monodroid-glue.cc

@@ -1475,6 +1475,25 @@ MonodroidRuntime::set_trace_options (void)
 	mono_jit_set_trace_options (value.get ());
 }
 
+#if defined (NET6)
+inline void
+MonodroidRuntime::set_profile_options ()
+{
+	// We want to avoid dynamic allocation, thus let’s create a buffer that can take both the property value and a
+	// path without allocation
+	dynamic_local_string<SENSIBLE_PATH_MAX + PROPERTY_VALUE_BUFFER_LEN> value;
+	{
+		dynamic_local_string<PROPERTY_VALUE_BUFFER_LEN> prop_value;
+		if (androidSystem.monodroid_get_system_property (Debug::DEBUG_MONO_PROFILE_PROPERTY, prop_value) == 0)
+			return;
+
+		value.assign (prop_value.get (), prop_value.length ());
+	}
+
+	// setenv(3) makes copies of its arguments
+	setenv ("DOTNET_DiagnosticPorts", value.get (), 1);
+}
+#else // def NET6
 inline void
 MonodroidRuntime::set_profile_options ()
 {
@@ -1566,6 +1585,7 @@ MonodroidRuntime::set_profile_options ()
 	log_warn (LOG_DEFAULT, "Initializing profiler with options: %s", value.get ());
 	debug.monodroid_profiler_load (androidSystem.get_runtime_libdir (), value.get (), output_path.get ());
 }
+#endif // ndef NET6
 
 /*
 Disable LLVM signal handlers.