feat: add maui profile command for Android startup tracing#60
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simonrozsival wants to merge 3 commits intodotnet:mainfrom
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feat: add maui profile command for Android startup tracing#60simonrozsival wants to merge 3 commits intodotnet:mainfrom
maui profile command for Android startup tracing#60simonrozsival wants to merge 3 commits intodotnet:mainfrom
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Adds a new top-level `maui profile` command that collects a startup .nettrace for a .NET MAUI Android app using dotnet-trace + dotnet-dsrouter. ## What's new ### `maui profile` command (ProfileCommand.cs) - Two-phase build: compile-only phase 1, then deploy+launch in phase 2 so the APK is built once and the trace collector starts before the app. - Starts dotnet-trace with `--dsrouter android-emu` (emulator) or `--dsrouter android` (physical device) for startup tracing. - Passes `DiagnosticSuspend=true` and `--resume-runtime` so the beginning of app startup is never missed. - Supports `--stopping-event-provider-name` / `--stopping-event-event-name` for automatic stop when the app signals startup is complete. - Automatically injects `dotnet-common,dotnet-sampled-thread-time` profiles alongside the stopping event provider so runtime and CPU-sampling events are still collected (specifying `--providers` alone would suppress the dotnet-trace defaults). - Clears inherited MSBuild SDK env vars before spawning child builds to prevent SDK version pollution when invoked via `dotnet run`. - Resolves macOS `/tmp` symlinks to avoid MAUI SourceGen MAUIG1001 errors. ### `Microsoft.Maui.StartupProfiling` helper package - Tiny opt-in assembly: add the NuGet reference and call `StartupProfilingMarker.Complete()` at the logical end of startup. - `[ModuleInitializer]` pre-registers the EventSource provider so dotnet-trace sees it before any user code runs. - `MAUI_STARTUP_PROFILING_AUTO_EXIT=1` env var causes the app to call `Environment.Exit(0)` after emitting the marker — useful in CI. - `IsProfilingSession` property lets apps skip work that skews traces. ### ProcessRunner changes - Added `environmentVariablesToRemove` parameter to strip inherited env vars before spawning subprocesses. ### Diagnostic improvements - `SpectreOutputFormatter` now shows native error output in error messages. - New error codes for prerequisite and config validation failures. ## Key technical notes - `--profile cpu-sampling` is incompatible with `--dsrouter` (Linux kernel perf only); `dotnet-sampled-thread-time` uses EventPipe and works. - `--stopping-event-provider-name` configures the stop condition but does NOT add the provider to the EventPipe session; `--providers` must also include it explicitly for events to be delivered. - Default collection (dotnet-common + dotnet-sampled-thread-time) must be injected explicitly whenever `--providers` is specified, because any `--providers` arg suppresses the implicit defaults. Closes dotnet#54 Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
…SDK) Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
eng/Common.props packs the repo-root README into every package at '/README.md'. The StartupProfiling project also includes its own README at the same path, causing NU5118 (treated as error in CI via --ci). Suppress NU5118 so the package-specific README is used. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Closes #54
Summary
Adds a new
maui profilecommand that collects a startup.nettracefor a .NET MAUI Android app usingdotnet-trace+dotnet-dsrouter, both invoked viadnxso no pre-installation is required.How it works
Two-phase build approach:
dotnet build)dotnet build -t:RunwithDiagnosticSuspend=true)Tool invocation via
dnx:dnx -y dotnet-dsrouter -- android-emu(orandroidfor physical devices)pid=<N>to stdout on startup — we parse that to get the PIDdnx -y dotnet-trace -- collect --process-id <pid>dotnet tool installrequired; always uses the latest published versionAuto-stop support via
Microsoft.Maui.StartupProfiling:ProjectReference, callStartupProfilingMarker.Complete()at logical startup end[ModuleInitializer]+ EventSource (Microsoft.Maui.StartupProfiling, eventStartupComplete)--stopping-event-provider-name Microsoft.Maui.StartupProfiling --stopping-event-event-name StartupCompleteto auto-stop the traceKey technical notes
--stopping-event-provider-nameonly configures the stop condition — the provider must also be in--providersfor EventPipe to actually deliver events. The command handles this automatically.cpu-samplingprofile is Linux-only in dotnet-trace 9+;dotnet-common,dotnet-sampled-thread-timeis the EventPipe equivalent that works with dsrouter.--providersarg suppresses dotnet-trace's implicit defaults, so we explicitly injectdotnet-common,dotnet-sampled-thread-timewhen a stopping event is configured.Testing
Open the resulting
.nettracein PerfView or Visual Studio Performance Profiler.