Registering a trace provider

Trace providers must register with the trace manager in order to participate in tracing. Drivers don't have to register as a trace provider since the devhost process does it through

To register a trace provider, you must do the following:

Note: For more information on the Fuchsia tracing system, see Fuchsia tracing system.

Register with the trace manager

To register as a trace provider, you can use the libtrace-provider library to provide an asynchronous loop in your component's code.

Note: For more information on tracing libraries, see Tracing libraries.

For example:

  • {C++}

    Note: This example uses fdio to set up the FIDL channel with Trace Manager. For more information, see fdio.

    #include <lib/async-loop/cpp/loop.h>
    #include <lib/async-loop/default.h>
    #include <lib/trace-provider/provider.h>
    // further includes
    int main(int argc, const char** argv) {
      // process argv
      async::Loop loop(&kAsyncLoopConfigAttachToCurrentThread);
      trace::TraceProviderWithFdio trace_provider(
          loop.dispatcher(), "my_trace_provider");
      // further setup
      return 0;
  • {C }

    #include <lib/async-loop/cpp/loop.h>
    #include <lib/async-loop/default.h>
    #include <lib/trace-provider/provider.h>
    int main(int argc, char** argv) {
      zx_status_t status;
      async_loop_t* loop;
      trace_provider_t* trace_provider;
      // Create a message loop.
      status = async_loop_create(&kAsyncLoopConfigNoAttachToCurrentThread, &loop);
      if (status != ZX_OK) exit(1);
      // Start a thread for the loop to run on.
      // Alternatively, use async_loop_run() to run on the current thread.
      status = async_loop_start_thread(loop, "loop", NULL);
      if (status != ZX_OK) exit(1);
      // Create the trace provider.
      async_dispatcher_t* dispatcher = async_loop_get_dispatcher(loop);
      trace_provider = trace_provider_create(dispatcher);
      if (!trace_provider) exit(1);
      // Do something...
      // Tear down.
      return 0;
  • {Rust}

    fn main() {
        // ...

Setup Routing

Ensure that your component requests the appropriate tracing capabilities by including the following in your component manifest:

  • {.cml file}

      include: [

This allows your component to communicate with trace_manager using the fuchsia.tracing.provider.Registry protocol as well as forward the offer to its children.

If your component uses a Chromium-based fuchsia.web service and you would like to be able to collect trace data from it, ensure that your Context is provided both the fuchsia.tracing.provider.Registry and fuchsia.tracing.perfetto.ProducerConnector capabilities.

Note: For more information on how capabilities are passed to the Context, see the documentation for fuchsia.web/CreateContextParams.service_directory.

Once you have registered your component as a trace provider, you can enable tracing in your code. For more information, see Adding tracing in your code.