Reland "Reland "[tracing] Use trace thread for gpu process to initialize tracing""

This is a reland of commit 972bef57b3
No change was made. LUCI Bisection misdiagnosed this CL as the
culprit of ASAN failures.

Original change's description:
> Reland "[tracing] Use trace thread for gpu process to initialize tracing"
>
> This is a reland of commit 44d8036a9d
>
> Previous CL was reverted because PostDelayedTask is dropped when
> Linux/ChromeOS sandboxing procedure stops the running thread. Such tasks
> need to be reposted. There're several places that PostDelayedTask to the
> trace_thread:
> - Some are through the PerfettoTaskRunner, that can be tracked easily.
> - One is directly posted by ConnectProducerSocketViaMojo, needs to be
>   special treated.
>
> This CL:
> - For trace_startup.h/.cc, add option to start tracing using the
>   trace_thread, and set will_trace_thread_restart to true on linux and
>   chromeos.
> - For perfetto_traced_process.h/.cc, postpone system tracing producer
>   socket connection to after sandbox entrance on linux & chromeos.
> - For perfetto_task_runner.h/.cc, store delayed tasks and post them when
>   internal taks_runner is reset.
>
> Original change's description:
> > [tracing] Use trace thread for gpu process to initialize tracing
> >
> > For non-zygote child gpu thread, start the trace thread in
> > ContentMainRunnerImpl() directly.
> >
> > For zygote child gpu thread, start the trace thread in RunZygote after
> > zygote fork and featurelist init.
> >
> > For Linux & ChromeOS, stop and restart the trace thread when entering
> > sandbox. Restarting trace thread has a caveat that delayed tasks would
> > will be lost unless we save them.
> >
> > This is [3/?] CL of enabling tracing prior to sandboxing.
> >
> > Bug: 380411640
> > Change-Id: I89fa94f63a709de0e3da4f8759098c9fff813bee
> > Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6180639
> > Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
> > Reviewed-by: Etienne Pierre-Doray <etiennep@chromium.org>
> > Commit-Queue: Kramer Ge <fangzhoug@chromium.org>
> > Cr-Commit-Position: refs/heads/main@{#1428704}
>
> Bug: 380411640, b/401194534
> Change-Id: I0f9172e48ee601f0236d84b0d8f784a11bd3d61a
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6462335
> Reviewed-by: Etienne Pierre-Doray <etiennep@chromium.org>
> Commit-Queue: Kramer Ge <fangzhoug@chromium.org>
> Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
> Reviewed-by: Zhenyao Mo <zmo@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#1451893}

Bug: 380411640, b/401194534
Change-Id: I32d42c00b0645783f00898ddc5167d655d773246
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6495650
Commit-Queue: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Zhenyao Mo <zmo@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Auto-Submit: Kramer Ge <fangzhoug@chromium.org>
Reviewed-by: Etienne Pierre-Doray <etiennep@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1453740}

base/tracing/perfetto_platform.cc

@@ -27,6 +27,7 @@ PerfettoPlatform::PerfettoPlatform(
     scoped_refptr<base::SequencedTaskRunner> task_runner,
     Options options)
     : process_name_prefix_(std::move(options.process_name_prefix)),
+      defer_delayed_tasks_(options.defer_delayed_tasks),
       task_runner_(std::move(task_runner)),
       thread_local_object_([](void* object) {
         delete static_cast<ThreadLocalObject*>(object);
@@ -49,7 +50,7 @@ std::unique_ptr<perfetto::base::TaskRunner> PerfettoPlatform::CreateTaskRunner(
   // TODO(b/242965112): Add support for the builtin task runner
   DCHECK(!perfetto_task_runner_);
   auto perfetto_task_runner =
-      std::make_unique<PerfettoTaskRunner>(task_runner_);
+      std::make_unique<PerfettoTaskRunner>(task_runner_, defer_delayed_tasks_);
   perfetto_task_runner_ = perfetto_task_runner->GetWeakPtr();
   return perfetto_task_runner;
 }

base/tracing/perfetto_platform.h

@@ -27,6 +27,10 @@ class BASE_EXPORT PerfettoPlatform : public perfetto::Platform {
     // TraceConfig.DataSource.producer_name_filter).
     std::string process_name_prefix = "org.chromium-";
 
+    // Defer delayed tasks to PerfettoTaskRunner until task runner resets after
+    // sandbox entry.
+    bool defer_delayed_tasks = false;
+
     // Work around https://bugs.llvm.org/show_bug.cgi?id=36684
     static Options Default() { return {}; }
   };
@@ -50,6 +54,7 @@ class BASE_EXPORT PerfettoPlatform : public perfetto::Platform {
 
  private:
   const std::string process_name_prefix_;
+  const bool defer_delayed_tasks_;
   WeakPtr<PerfettoTaskRunner> perfetto_task_runner_;
   scoped_refptr<base::SequencedTaskRunner> task_runner_;
   ThreadLocalStorage::Slot thread_local_object_;

base/tracing/perfetto_task_runner.cc

@@ -22,8 +22,10 @@
 namespace base::tracing {
 
 PerfettoTaskRunner::PerfettoTaskRunner(
-    scoped_refptr<base::SequencedTaskRunner> task_runner)
+    scoped_refptr<base::SequencedTaskRunner> task_runner,
-    : task_runner_(std::move(task_runner)) {
+    bool defer_delayed_tasks)
+    : task_runner_(std::move(task_runner)),
+      defer_delayed_tasks_(defer_delayed_tasks) {
   CHECK(task_runner_);
 }
 
@@ -40,6 +42,10 @@ void PerfettoTaskRunner::PostTask(std::function<void()> task) {
 
 void PerfettoTaskRunner::PostDelayedTask(std::function<void()> task,
                                          uint32_t delay_ms) {
+  if (defer_delayed_tasks_ && delay_ms) {
+    deferred_delayed_tasks_.emplace_back(task, delay_ms);
+    return;
+  }
   base::ScopedDeferTaskPosting::PostOrDefer(
       task_runner_, FROM_HERE,
       base::BindOnce(
@@ -117,6 +123,11 @@ void PerfettoTaskRunner::RemoveFileDescriptorWatch(
 void PerfettoTaskRunner::ResetTaskRunner(
     scoped_refptr<base::SequencedTaskRunner> task_runner) {
   task_runner_ = std::move(task_runner);
+  defer_delayed_tasks_ = false;
+  for (auto& task : deferred_delayed_tasks_) {
+    PostDelayedTask(task.task, task.delay);
+  }
+  deferred_delayed_tasks_.clear();
 }
 
 #if (BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_NACL)) || BUILDFLAG(IS_FUCHSIA)
@@ -127,4 +138,12 @@ PerfettoTaskRunner::FDControllerAndCallback::~FDControllerAndCallback() =
     default;
 #endif  // (BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_NACL)) || BUILDFLAG(IS_FUCHSIA)
 
+PerfettoTaskRunner::DeferredTask::DeferredTask(std::function<void()> task,
+                                               uint32_t delay)
+    : task(std::move(task)), delay(delay) {}
+
+PerfettoTaskRunner::DeferredTask::DeferredTask(DeferredTask&& task) = default;
+
+PerfettoTaskRunner::DeferredTask::~DeferredTask() = default;
+
 }  // namespace base::tracing

base/tracing/perfetto_task_runner.h

@@ -5,6 +5,8 @@
 #ifndef BASE_TRACING_PERFETTO_TASK_RUNNER_H_
 #define BASE_TRACING_PERFETTO_TASK_RUNNER_H_
 
+#include <vector>
+
 #include "base/base_export.h"
 #include "base/cancelable_callback.h"
 #include "base/memory/weak_ptr.h"
@@ -29,7 +31,8 @@ namespace tracing {
 // to provide it to Perfetto.
 class BASE_EXPORT PerfettoTaskRunner : public perfetto::base::TaskRunner {
  public:
-  explicit PerfettoTaskRunner(scoped_refptr<base::SequencedTaskRunner>);
+  explicit PerfettoTaskRunner(scoped_refptr<base::SequencedTaskRunner>,
+                              bool defer_delayed_tasks = false);
   ~PerfettoTaskRunner() override;
   PerfettoTaskRunner(const PerfettoTaskRunner&) = delete;
   void operator=(const PerfettoTaskRunner&) = delete;
@@ -58,6 +61,21 @@ class BASE_EXPORT PerfettoTaskRunner : public perfetto::base::TaskRunner {
  private:
   scoped_refptr<base::SequencedTaskRunner> task_runner_;
 
+  struct DeferredTask {
+    DeferredTask(std::function<void()> task, uint32_t delay);
+    DeferredTask(const DeferredTask&) = delete;
+    DeferredTask& operator=(const DeferredTask&) = delete;
+    DeferredTask(DeferredTask&& task);
+    ~DeferredTask();
+
+    std::function<void()> task;
+    uint32_t delay;
+  };
+
+  // Delayed tasks will be posted when `task_runner_` resets.
+  std::vector<DeferredTask> deferred_delayed_tasks_;
+  bool defer_delayed_tasks_;
+
 #if (BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_NACL)) || BUILDFLAG(IS_FUCHSIA)
   // FDControllerAndCallback keeps track of the state of FD watching:
   // * |controller| has value: FD watching is added. |callback| is nullopt.

content/app/content_main_runner_impl.cc

@@ -662,7 +662,18 @@ NO_STACK_PROTECTOR int RunZygote(ContentMainDelegate* delegate) {
 
   MainFunctionParams main_params(command_line);
   main_params.zygote_child = true;
-  main_params.needs_startup_tracing_after_mojo_init = true;
+
+  if (process_type == switches::kGpuProcess) {
+    // Once Zygote forks and feature list initializes we can start a thread to
+    // begin tracing immediately.
+    // TODO(https://crbug.com/380411640): Enable for more processes other than
+    // GPU process.
+    tracing::EnableStartupTracingIfNeeded(/*with_thread=*/true);
+    tracing::InitTracingPostFeatureList(/*enable_consumer=*/false);
+    main_params.needs_startup_tracing_after_mojo_init = false;
+  } else {
+    main_params.needs_startup_tracing_after_mojo_init = true;
+  }
 
   // The hang watcher needs to be created once the feature list is available
   // but before the IO thread is started.
@@ -892,15 +903,27 @@ int ContentMainRunnerImpl::Initialize(ContentMainParams params) {
 #if BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_ANDROID) && !BUILDFLAG(IS_MAC)
   // A sandboxed process won't be able to allocate the SMB needed for startup
   // tracing until Mojo IPC support is brought up, at which point the Mojo
-  // broker will transparently broker the SMB creation.
+  // broker will transparently broker the SMB creation. Unless the sandboxed
-  if (!sandbox::policy::IsUnsandboxedSandboxType(
+  // process stops the trace threads when entering sandbox.
+  // TODO(https://crbug.com/380411640): Implement for other processes other than
+  // GPU process.
+  if (process_type != switches::kGpuProcess &&
+      !sandbox::policy::IsUnsandboxedSandboxType(
           sandbox::policy::SandboxTypeFromCommandLine(command_line))) {
     enable_startup_tracing = false;
     needs_startup_tracing_after_mojo_init_ = true;
   }
 #endif  // BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_ANDROID) && !BUILDFLAG(IS_MAC)
   if (enable_startup_tracing) {
-    tracing::EnableStartupTracingIfNeeded();
+    if (process_type == switches::kGpuProcess) {
+      // Without Zygote and posix sandbox we can start a thread to begin tracing
+      // immediately.
+      // TODO(https://crbug.com/380411640): Enable for more processes other than
+      // GPU process.
+      tracing::EnableStartupTracingIfNeeded(/*with_thread=*/true);
+    } else {
+      tracing::EnableStartupTracingIfNeeded(/*with_thread=*/false);
+    }
   }
   TRACE_EVENT0("startup,benchmark,rail", "ContentMainRunnerImpl::Initialize");
 
@@ -1116,6 +1139,9 @@ NO_STACK_PROTECTOR int ContentMainRunnerImpl::Run() {
               ContentMainDelegate::InvokedInChildProcess())) {
         InitializeFieldTrialAndFeatureList();
       }
+      if (process_type == switches::kGpuProcess) {
+        tracing::InitTracingPostFeatureList(/*enable_consumer=*/false);
+      }
       if (delegate_->ShouldInitializeMojo(
               ContentMainDelegate::InvokedInChildProcess())) {
         InitializeMojoCore();

content/gpu/gpu_main.cc

@@ -28,6 +28,7 @@
 #include "base/task/single_thread_task_executor.h"
 #include "base/task/thread_pool/thread_pool_instance.h"
 #include "base/threading/platform_thread.h"
+#include "base/threading/thread.h"
 #include "base/time/time.h"
 #include "base/timer/hi_res_timer_manager.h"
 #include "base/trace_event/trace_event.h"
@@ -44,6 +45,7 @@
 #include "content/public/common/content_switches.h"
 #include "content/public/common/main_function_params.h"
 #include "content/public/common/result_codes.h"
+#include "content/public/common/zygote/zygote_buildflags.h"
 #include "content/public/gpu/content_gpu_client.h"
 #include "gpu/command_buffer/service/gpu_switches.h"
 #include "gpu/config/gpu_driver_bug_list.h"
@@ -59,6 +61,7 @@
 #include "media/gpu/buildflags.h"
 #include "mojo/public/cpp/bindings/interface_endpoint_client.h"
 #include "mojo/public/cpp/bindings/sync_call_restrictions.h"
+#include "services/tracing/public/cpp/perfetto/perfetto_traced_process.h"
 #include "services/tracing/public/cpp/trace_startup.h"
 #include "services/tracing/public/cpp/trace_startup_config.h"
 #include "third_party/angle/src/gpu_info_util/SystemInfo.h"
@@ -196,11 +199,8 @@ class ContentSandboxHelper : public gpu::GpuSandboxHelper {
 
 // Main function for starting the Gpu process.
 int GpuMain(MainFunctionParams parameters) {
-  if (tracing::TraceStartupConfig::GetInstance().IsEnabled()) {
+  TRACE_EVENT("gpu,startup", "GpuMain");
-    gl::StartupTrace::Startup();
-  }
 
-  TRACE_EVENT0("gpu", "GpuMain");
   base::CurrentProcess::GetInstance().SetProcessType(
       base::CurrentProcessType::PROCESS_GPU);
 
@@ -310,7 +310,6 @@ int GpuMain(MainFunctionParams parameters) {
             base::MessagePumpType::DEFAULT);
 #endif
   }
-  gl::StartupTrace::GetInstance()->BindToCurrentThread();
 
   base::PlatformThread::SetName("CrGpuMain");
   mojo::InterfaceEndpointClient::SetThreadNameSuffixForMetrics("GpuMain");
@@ -436,7 +435,6 @@ int GpuMain(MainFunctionParams parameters) {
   }
 
   DCHECK(tracing::IsTracingInitialized());
-  gl::StartupTrace::StarupDone();
 
   {
     TRACE_EVENT0("gpu", "Run Message Loop");
@@ -460,6 +458,14 @@ bool StartSandboxLinux(gpu::GpuWatchdogThread* watchdog_thread,
     sandbox::policy::SandboxLinux::GetInstance()->StopThread(watchdog_thread);
   }
 
+  base::Thread* trace_thread =
+      tracing::IsTracingInitialized()
+          ? tracing::PerfettoTracedProcess::GetTraceThread()
+          : nullptr;
+  if (trace_thread) {
+    sandbox::policy::SandboxLinux::GetInstance()->StopThread(trace_thread);
+  }
+
   // SandboxLinux::InitializeSandbox() must always be called
   // with only one thread.
   sandbox::policy::SandboxLinux::Options sandbox_options;
@@ -509,6 +515,10 @@ bool StartSandboxLinux(gpu::GpuWatchdogThread* watchdog_thread,
     watchdog_thread->Start();
   }
 
+  if (trace_thread) {
+    tracing::PerfettoTracedProcess::Get().RestartThreadInSandbox();
+  }
+
   return res;
 }
 #endif  // BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS)

services/tracing/public/cpp/perfetto/perfetto_traced_process.cc

@@ -108,7 +108,7 @@ void ConnectProducerSocketViaMojo(perfetto::CreateSocketCallback cb,
 
 // Wrapper for |ConnectProducerSocketViaMojo| to be used as a function pointer.
 void ConnectProducerSocketAsync(perfetto::CreateSocketCallback cb) {
-  ConnectProducerSocketViaMojo(std::move(cb), base::Milliseconds(100));
+  PerfettoTracedProcess::Get().DeferOrConnectProducerSocket(std::move(cb));
 }
 #endif
 
@@ -171,19 +171,22 @@ void PerfettoTracedProcess::DataSourceBase::ResetTaskRunner(
   GetDataSourceTaskRunner() = task_runner;
 }
 
-// static
 void PerfettoTracedProcess::RestartThreadInSandbox() {
-  base::Thread* trace_thread = PerfettoTracedProcess::GetTraceThread();
+  CHECK(trace_process_thread_->StartWithOptions(
-  if (trace_thread->StartWithOptions(
+      base::Thread::Options(base::MessagePumpType::IO, 0)));
-          base::Thread::Options(base::MessagePumpType::IO, 0))) {
+  DETACH_FROM_SEQUENCE(sequence_checker_);
-    DETACH_FROM_SEQUENCE(PerfettoTracedProcess::Get().sequence_checker_);
+  task_runner_ = trace_process_thread_->task_runner();
-    PerfettoTracedProcess::Get().task_runner_ = trace_thread->task_runner();
+  platform_->ResetTaskRunner(trace_process_thread_->task_runner());
-    PerfettoTracedProcess::Get().platform_->ResetTaskRunner(
+  DataSourceBase::ResetTaskRunner(trace_process_thread_->task_runner());
-        trace_thread->task_runner());
+  tracing_backend_->DetachFromMuxerSequence();
-    DataSourceBase::ResetTaskRunner(trace_thread->task_runner());
+  CustomEventRecorder::GetInstance()->DetachFromSequence();
-    PerfettoTracedProcess::Get().tracing_backend_->DetachFromMuxerSequence();
+  will_trace_thread_restart_ = false;
-    CustomEventRecorder::GetInstance()->DetachFromSequence();
+#if BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_ANDROID)
+  if (system_tracing_producer_socket_cb_) {
+    task_runner_->PostTask(FROM_HERE,
+                           std::move(system_tracing_producer_socket_cb_));
   }
+#endif  // BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_ANDROID)
 }
 
 // static
@@ -200,8 +203,10 @@ PerfettoTracedProcess& PerfettoTracedProcess::MaybeCreateInstance() {
 }
 
 // static
-PerfettoTracedProcess& PerfettoTracedProcess::MaybeCreateInstanceWithThread() {
+PerfettoTracedProcess& PerfettoTracedProcess::MaybeCreateInstanceWithThread(
-  static base::NoDestructor<PerfettoTracedProcess> traced_process{};
+    bool will_trace_thread_restart) {
+  static base::NoDestructor<PerfettoTracedProcess> traced_process(
+      will_trace_thread_restart);
   return *traced_process;
 }
 
@@ -217,15 +222,18 @@ PerfettoTracedProcess& PerfettoTracedProcess::Get() {
   return *g_instance;
 }
 
-PerfettoTracedProcess::PerfettoTracedProcess()
+PerfettoTracedProcess::PerfettoTracedProcess(bool will_trace_thread_restart)
     : trace_process_thread_(std::make_unique<base::Thread>("PerfettoTrace")),
       task_runner_(trace_process_thread_->StartWithOptions(
                        base::Thread::Options(base::MessagePumpType::IO, 0))
                        ? trace_process_thread_->task_runner()
                        : nullptr),
-      platform_(
+      will_trace_thread_restart_(will_trace_thread_restart),
-          std::make_unique<base::tracing::PerfettoPlatform>(task_runner_)),
       tracing_backend_(std::make_unique<PerfettoTracingBackend>()) {
+  base::tracing::PerfettoPlatform::Options options{
+      .defer_delayed_tasks = will_trace_thread_restart_};
+  platform_ =
+      std::make_unique<base::tracing::PerfettoPlatform>(task_runner_, options);
   DETACH_FROM_SEQUENCE(sequence_checker_);
   CHECK_EQ(g_instance, nullptr);
   CHECK(task_runner_);
@@ -366,6 +374,20 @@ void PerfettoTracedProcess::SetupClientLibrary(bool enable_consumer) {
   CustomEventRecorder::GetInstance();
 }
 
+#if BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_ANDROID)
+void PerfettoTracedProcess::DeferOrConnectProducerSocket(
+    perfetto::CreateSocketCallback cb) {
+  CHECK(!system_tracing_producer_socket_cb_);
+  // Hold off the attempts to get socket fd until trace thread restarts.
+  if (will_trace_thread_restart_) {
+    system_tracing_producer_socket_cb_ = base::BindOnce(
+        ConnectProducerSocketViaMojo, cb, base::Milliseconds(100));
+  } else {
+    ConnectProducerSocketViaMojo(cb, base::Milliseconds(100));
+  }
+}
+#endif  // BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_ANDROID)
+
 void PerfettoTracedProcess::OnThreadPoolAvailable(bool enable_consumer) {
   thread_pool_started_ = true;
   SetupClientLibrary(enable_consumer);

services/tracing/public/cpp/perfetto/perfetto_traced_process.h

@@ -97,6 +97,9 @@ class COMPONENT_EXPORT(TRACING_CPP) PerfettoTracedProcess final
     // By default, data source callbacks (e.g., Start/StopTracingImpl) are
     // called on PerfettoTracedProcess::GetTaskRunner()'s sequence. This method
     // allows overriding that task runner.
+    // Note: The task_runner's thread may stop and restart for Linux/ChromeOS
+    // sandboxing so the task_runner can change and delayed tasks posted to it
+    // may be silently dropped.
     virtual base::SequencedTaskRunner* GetTaskRunner();
 
     static void ResetTaskRunner(
@@ -152,8 +155,8 @@ class COMPONENT_EXPORT(TRACING_CPP) PerfettoTracedProcess final
     perfetto::DataSourceConfig data_source_config_;
   };
 
-  // Restart the trace thread and replace the task_runner for tracing.
+  // Restarts the trace thread and replaces the task_runner for tracing.
-  static void RestartThreadInSandbox();
+  void RestartThreadInSandbox();
 
   // Returns the process-wide ptr to the trace thread, returns nullptr if the
   // task_runner for tracing is from the thread-pool.
@@ -161,7 +164,8 @@ class COMPONENT_EXPORT(TRACING_CPP) PerfettoTracedProcess final
 
   // Creates the process-wide instance of the PerfettoTracedProcess.
   static PerfettoTracedProcess& MaybeCreateInstance();
-  static PerfettoTracedProcess& MaybeCreateInstanceWithThread();
+  static PerfettoTracedProcess& MaybeCreateInstanceWithThread(
+      bool will_trace_thread_restart);
   static PerfettoTracedProcess& MaybeCreateInstanceForTesting();
 
   // Returns the process-wide instance of the PerfettoTracedProcess.
@@ -228,11 +232,15 @@ class COMPONENT_EXPORT(TRACING_CPP) PerfettoTracedProcess final
       const perfetto::TraceConfig& config,
       const perfetto::Tracing::SetupStartupTracingOpts& opts);
 
+#if BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_ANDROID)
+  void DeferOrConnectProducerSocket(perfetto::CreateSocketCallback cb);
+#endif  // BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_ANDROID)
+
  private:
   friend class base::NoDestructor<PerfettoTracedProcess>;
 
   // Default constructor would create a dedicated thread for tracing
-  PerfettoTracedProcess();
+  explicit PerfettoTracedProcess(bool will_trace_thread_restart);
   explicit PerfettoTracedProcess(
       scoped_refptr<base::SequencedTaskRunner> task_runner);
 
@@ -261,6 +269,11 @@ class COMPONENT_EXPORT(TRACING_CPP) PerfettoTracedProcess final
   std::unique_ptr<base::Thread> trace_process_thread_;
   scoped_refptr<base::SequencedTaskRunner> task_runner_;
 
+  bool will_trace_thread_restart_ = false;
+#if BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_ANDROID)
+  base::OnceClosure system_tracing_producer_socket_cb_;
+#endif  // BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_ANDROID)
+
   // Platform implementation for the Perfetto client library.
   std::unique_ptr<base::tracing::PerfettoPlatform> platform_;
   std::unique_ptr<PerfettoTracingBackend> tracing_backend_;

services/tracing/public/cpp/trace_startup.cc

@@ -46,17 +46,15 @@ using base::trace_event::TraceLog;
 }  // namespace
 
 bool g_tracing_initialized_after_featurelist = false;
+bool g_tracing_with_thread = false;
 
 bool IsTracingInitialized() {
   return g_tracing_initialized_after_featurelist;
 }
 
-void EnableStartupTracingIfNeeded() {
+void EnableStartupTracingIfNeeded(bool with_thread) {
   RegisterTracedValueProtoWriter();
 
-  // Create the PerfettoTracedProcess.
-  PerfettoTracedProcess::MaybeCreateInstance();
-
   // Initialize the client library's TrackRegistry to support trace points
   // during startup tracing. We don't setup the client library completely here
   // yet, because we don't have field trials loaded yet (which influence which
@@ -65,6 +63,20 @@ void EnableStartupTracingIfNeeded() {
   // setting up the client library?
   perfetto::internal::TrackRegistry::InitializeInstance();
 
+  // Create the PerfettoTracedProcess.
+  if (with_thread) {
+    g_tracing_with_thread = true;
+#if BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS)
+    PerfettoTracedProcess::MaybeCreateInstanceWithThread(
+        /*will_trace_thread_restart=*/true);
+#else
+    PerfettoTracedProcess::MaybeCreateInstanceWithThread(
+        /*will_trace_thread_restart=*/false);
+#endif
+  } else {
+    PerfettoTracedProcess::MaybeCreateInstance();
+  }
+
   // Ensure TraceLog is initialized first.
   // https://crbug.com/764357
   TraceLog::GetInstance();
@@ -105,7 +117,9 @@ void InitTracingPostFeatureList(bool enable_consumer) {
   DCHECK(base::FeatureList::GetInstance());
 
   // Create the PerfettoTracedProcess.
-  PerfettoTracedProcess::MaybeCreateInstance();
+  if (!g_tracing_with_thread) {
+    PerfettoTracedProcess::MaybeCreateInstance();
+  }
   PerfettoTracedProcess::Get().OnThreadPoolAvailable(enable_consumer);
 #if BUILDFLAG(IS_WIN)
   tracing::EnableETWExport();

services/tracing/public/cpp/trace_startup.h

@@ -35,7 +35,8 @@ bool COMPONENT_EXPORT(TRACING_CPP) IsTracingInitialized();
 // TODO(eseckler): Consider allocating the SMB in parent processes outside the
 // sandbox and supply it via the command line. Then, we can revert to call this
 // earlier and from fewer places again.
-void COMPONENT_EXPORT(TRACING_CPP) EnableStartupTracingIfNeeded();
+void COMPONENT_EXPORT(TRACING_CPP)
+    EnableStartupTracingIfNeeded(bool with_thread = false);
 
 // Enable startup tracing for the current process with the provided config. Sets
 // up ProducerClient and trace event and/or sampler profiler data sources, and

ui/gl/startup_trace.h

@@ -77,20 +77,6 @@ class GL_EXPORT StartupTrace {
 
 }  // namespace gl
 
-// Generate a unique variable name with a given prefix.
+#define GPU_STARTUP_TRACE_EVENT(name) TRACE_EVENT("gpu,startup", name);
-#define GPU_STARTUP_TRACE_INTERNAL_CONCAT2(a, b) a##b
-#define GPU_STARTUP_TRACE_INTERNAL_CONCAT(a, b) \
-  GPU_STARTUP_TRACE_INTERNAL_CONCAT2(a, b)
-#define GPU_STARTUP_TRACE_UID(prefix) \
-  GPU_STARTUP_TRACE_INTERNAL_CONCAT(prefix, __LINE__)
-
-#define GPU_STARTUP_TRACE_EVENT(name)                                       \
-  gl::StartupTrace::ScopedStage GPU_STARTUP_TRACE_UID(scoped_gpu_trace){0}; \
-  if (gl::StartupTrace::IsEnabled()) {                                      \
-    GPU_STARTUP_TRACE_UID(scoped_gpu_trace) =                               \
-        gl::StartupTrace::GetInstance()->AddStage(name);                    \
-  } else {                                                                  \
-    TRACE_EVENT0("gpu,startup", name);                                      \
-  }
 
 #endif  // UI_GL_STARTUP_TRACE_H_