Define thread priority enum and set thread priority for all threads in Engine

fml/concurrent_message_loop.cc

@@ -21,8 +21,8 @@ ConcurrentMessageLoop::ConcurrentMessageLoop(size_t worker_count)
     : worker_count_(std::max<size_t>(worker_count, 1ul)) {
   for (size_t i = 0; i < worker_count_; ++i) {
     workers_.emplace_back([i, this]() {
-      fml::Thread::SetCurrentThreadName(
-          std::string{"io.worker." + std::to_string(i + 1)});
+      fml::Thread::SetCurrentThreadName(fml::Thread::ThreadConfig(
+          std::string{"io.worker." + std::to_string(i + 1)}));
       WorkerMain();
     });
   }

fml/thread.cc

@@ -8,6 +8,7 @@
 
 #include <memory>
 #include <string>
+#include <utility>
 
 #include "flutter/fml/build_config.h"
 #include "flutter/fml/message_loop.h"
@@ -23,38 +24,6 @@
 
 namespace fml {
 
-Thread::Thread(const std::string& name) : joined_(false) {
-  fml::AutoResetWaitableEvent latch;
-  fml::RefPtr<fml::TaskRunner> runner;
-  thread_ = std::make_unique<std::thread>([&latch, &runner, name]() -> void {
-    SetCurrentThreadName(name);
-    fml::MessageLoop::EnsureInitializedForCurrentThread();
-    auto& loop = MessageLoop::GetCurrent();
-    runner = loop.GetTaskRunner();
-    latch.Signal();
-    loop.Run();
-  });
-  latch.Wait();
-  task_runner_ = runner;
-}
-
-Thread::~Thread() {
-  Join();
-}
-
-fml::RefPtr<fml::TaskRunner> Thread::GetTaskRunner() const {
-  return task_runner_;
-}
-
-void Thread::Join() {
-  if (joined_) {
-    return;
-  }
-  joined_ = true;
-  task_runner_->PostTask([]() { MessageLoop::GetCurrent().Terminate(); });
-  thread_->join();
-}
-
 #if defined(FML_OS_WIN)
 // The information on how to set the thread name comes from
 // a MSDN article: http://msdn2.microsoft.com/en-us/library/xcb2z8hs.aspx
@@ -67,7 +36,7 @@ typedef struct tagTHREADNAME_INFO {
 } THREADNAME_INFO;
 #endif
 
-void Thread::SetCurrentThreadName(const std::string& name) {
+void SetThreadName(const std::string& name) {
   if (name == "") {
     return;
   }
@@ -94,4 +63,46 @@ void Thread::SetCurrentThreadName(const std::string& name) {
 #endif
 }
 
+void Thread::SetCurrentThreadName(const Thread::ThreadConfig& config) {
+  SetThreadName(config.name);
+}
+
+Thread::Thread(const std::string& name)
+    : Thread(Thread::SetCurrentThreadName, ThreadConfig(name)) {}
+
+Thread::Thread(const ThreadConfigSetter& setter, const ThreadConfig& config)
+    : joined_(false) {
+  fml::AutoResetWaitableEvent latch;
+  fml::RefPtr<fml::TaskRunner> runner;
+
+  thread_ = std::make_unique<std::thread>(
+      [&latch, &runner, setter, config]() -> void {
+        setter(config);
+        fml::MessageLoop::EnsureInitializedForCurrentThread();
+        auto& loop = MessageLoop::GetCurrent();
+        runner = loop.GetTaskRunner();
+        latch.Signal();
+        loop.Run();
+      });
+  latch.Wait();
+  task_runner_ = runner;
+}
+
+Thread::~Thread() {
+  Join();
+}
+
+fml::RefPtr<fml::TaskRunner> Thread::GetTaskRunner() const {
+  return task_runner_;
+}
+
+void Thread::Join() {
+  if (joined_) {
+    return;
+  }
+  joined_ = true;
+  task_runner_->PostTask([]() { MessageLoop::GetCurrent().Terminate(); });
+  thread_->join();
+}
+
 }  // namespace fml

fml/thread.h

@@ -6,7 +6,9 @@
 #define FLUTTER_FML_THREAD_H_
 
 #include <atomic>
+#include <functional>
 #include <memory>
+#include <string>
 #include <thread>
 
 #include "flutter/fml/macros.h"
@@ -16,19 +18,52 @@ namespace fml {
 
 class Thread {
  public:
+  /// Valid values for priority of Thread.
+  enum class ThreadPriority : int {
+    /// Suitable for threads that shouldn't disrupt high priority work.
+    BACKGROUND,
+    /// Default priority level.
+    NORMAL,
+    /// Suitable for threads which generate data for the display.
+    DISPLAY,
+    /// Suitable for thread which raster data.
+    RASTER,
+  };
+
+  /// The ThreadConfig is the thread info include thread name, thread priority.
+  struct ThreadConfig {
+    ThreadConfig(const std::string& name, ThreadPriority priority)
+        : name(name), priority(priority) {}
+
+    explicit ThreadConfig(const std::string& name)
+        : ThreadConfig(name, ThreadPriority::NORMAL) {}
+
+    ThreadConfig() : ThreadConfig("", ThreadPriority::NORMAL) {}
+
+    std::string name;
+    ThreadPriority priority;
+  };
+
+  using ThreadConfigSetter = std::function<void(const ThreadConfig&)>;
+
   explicit Thread(const std::string& name = "");
 
+  explicit Thread(const ThreadConfigSetter& setter,
+                  const ThreadConfig& config = ThreadConfig());
+
   ~Thread();
 
   fml::RefPtr<fml::TaskRunner> GetTaskRunner() const;
 
   void Join();
 
-  static void SetCurrentThreadName(const std::string& name);
+  static void SetCurrentThreadName(const ThreadConfig& config);
 
  private:
   std::unique_ptr<std::thread> thread_;
+
   fml::RefPtr<fml::TaskRunner> task_runner_;
+
   std::atomic_bool joined_;
 
   FML_DISALLOW_COPY_AND_ASSIGN(Thread);

fml/thread_unittests.cc

@@ -4,6 +4,18 @@
 
 #include "flutter/fml/thread.h"
 
+#if defined(OS_MACOSX) || defined(OS_LINUX) || defined(OS_ANDROID)
+#define FLUTTER_PTHREAD_SUPPORTED 1
+#else
+#define FLUTTER_PTHREAD_SUPPORTED 0
+#endif
+
+#if FLUTTER_PTHREAD_SUPPORTED
+#include <pthread.h>
+#else
+#endif
+
+#include <memory>
 #include "gtest/gtest.h"
 
 TEST(Thread, CanStartAndEnd) {
@@ -24,3 +36,77 @@ TEST(Thread, HasARunningMessageLoop) {
   thread.Join();
   ASSERT_TRUE(done);
 }
+
+#if FLUTTER_PTHREAD_SUPPORTED
+TEST(Thread, ThreadNameCreatedWithConfig) {
+  const std::string name = "Thread1";
+  fml::Thread thread(name);
+
+  bool done = false;
+  thread.GetTaskRunner()->PostTask([&done, &name]() {
+    done = true;
+    char thread_name[8];
+    pthread_t current_thread = pthread_self();
+    pthread_getname_np(current_thread, thread_name, 8);
+    ASSERT_EQ(thread_name, name);
+  });
+  thread.Join();
+  ASSERT_TRUE(done);
+}
+
+static void MockThreadConfigSetter(const fml::Thread::ThreadConfig& config) {
+  // set thread name
+  fml::Thread::SetCurrentThreadName(config);
+
+  pthread_t tid = pthread_self();
+  struct sched_param param;
+  int policy = SCHED_OTHER;
+  switch (config.priority) {
+    case fml::Thread::ThreadPriority::DISPLAY:
+      param.sched_priority = 10;
+      break;
+    default:
+      param.sched_priority = 1;
+  }
+  pthread_setschedparam(tid, policy, &param);
+}
+
+TEST(Thread, ThreadPriorityCreatedWithConfig) {
+  const std::string thread1_name = "Thread1";
+  const std::string thread2_name = "Thread2";
+
+  fml::Thread thread(MockThreadConfigSetter,
+                     fml::Thread::ThreadConfig(
+                         thread1_name, fml::Thread::ThreadPriority::NORMAL));
+  bool done = false;
+
+  struct sched_param param;
+  int policy;
+  thread.GetTaskRunner()->PostTask([&]() {
+    done = true;
+    char thread_name[8];
+    pthread_t current_thread = pthread_self();
+    pthread_getname_np(current_thread, thread_name, 8);
+    pthread_getschedparam(current_thread, &policy, &param);
+    ASSERT_EQ(thread_name, thread1_name);
+    ASSERT_EQ(policy, SCHED_OTHER);
+    ASSERT_EQ(param.sched_priority, 1);
+  });
+
+  fml::Thread thread2(MockThreadConfigSetter,
+                      fml::Thread::ThreadConfig(
+                          thread2_name, fml::Thread::ThreadPriority::DISPLAY));
+  thread2.GetTaskRunner()->PostTask([&]() {
+    done = true;
+    char thread_name[8];
+    pthread_t current_thread = pthread_self();
+    pthread_getname_np(current_thread, thread_name, 8);
+    pthread_getschedparam(current_thread, &policy, &param);
+    ASSERT_EQ(thread_name, thread2_name);
+    ASSERT_EQ(policy, SCHED_OTHER);
+    ASSERT_EQ(param.sched_priority, 10);
+  });
+  thread.Join();
+  ASSERT_TRUE(done);
+}
+#endif

lib/ui/ui_benchmarks.cc

@@ -20,9 +20,9 @@ class Fixture : public testing::FixtureTest {
 };
 
 static void BM_PlatformMessageResponseDartComplete(benchmark::State& state) {
-  ThreadHost thread_host("test",
-                         ThreadHost::Type::Platform | ThreadHost::Type::RASTER |
-                             ThreadHost::Type::IO | ThreadHost::Type::UI);
+  ThreadHost thread_host(ThreadHost::ThreadHostConfig(
+      "test", ThreadHost::Type::Platform | ThreadHost::Type::RASTER |
+                  ThreadHost::Type::IO | ThreadHost::Type::UI));
   TaskRunners task_runners("test", thread_host.platform_thread->GetTaskRunner(),
                            thread_host.raster_thread->GetTaskRunner(),
                            thread_host.ui_thread->GetTaskRunner(),
@@ -68,9 +68,9 @@ static void BM_PlatformMessageResponseDartComplete(benchmark::State& state) {
 }
 
 static void BM_PathVolatilityTracker(benchmark::State& state) {
-  ThreadHost thread_host("test",
-                         ThreadHost::Type::Platform | ThreadHost::Type::RASTER |
-                             ThreadHost::Type::IO | ThreadHost::Type::UI);
+  ThreadHost thread_host(ThreadHost::ThreadHostConfig(
+      "test", ThreadHost::Type::Platform | ThreadHost::Type::RASTER |
+                  ThreadHost::Type::IO | ThreadHost::Type::UI));
   TaskRunners task_runners("test", thread_host.platform_thread->GetTaskRunner(),
                            thread_host.raster_thread->GetTaskRunner(),
                            thread_host.ui_thread->GetTaskRunner(),

shell/common/shell_benchmarks.cc

@@ -43,10 +43,10 @@ static void StartupAndShutdownShell(benchmark::State& state,
       };
     }
 
-    thread_host = std::make_unique<ThreadHost>(
+    thread_host = std::make_unique<ThreadHost>(ThreadHost::ThreadHostConfig(
         "io.flutter.bench.", ThreadHost::Type::Platform |
                                  ThreadHost::Type::RASTER |
-                                 ThreadHost::Type::IO | ThreadHost::Type::UI);
+                                 ThreadHost::Type::IO | ThreadHost::Type::UI));
 
     TaskRunners task_runners("test",
                              thread_host->platform_thread->GetTaskRunner(),

shell/common/shell_unittests.cc

@@ -264,9 +264,10 @@ TEST_F(ShellTest, InitializeWithInvalidThreads) {
 TEST_F(ShellTest, InitializeWithDifferentThreads) {
   ASSERT_FALSE(DartVMRef::IsInstanceRunning());
   Settings settings = CreateSettingsForFixture();
-  ThreadHost thread_host("io.flutter.test." + GetCurrentTestName() + ".",
-                         ThreadHost::Type::Platform | ThreadHost::Type::RASTER |
-                             ThreadHost::Type::IO | ThreadHost::Type::UI);
+  ThreadHost thread_host(ThreadHost::ThreadHostConfig(
+      "io.flutter.test." + GetCurrentTestName() + ".",
+      ThreadHost::Type::Platform | ThreadHost::Type::RASTER |
+          ThreadHost::Type::IO | ThreadHost::Type::UI));
   TaskRunners task_runners("test", thread_host.platform_thread->GetTaskRunner(),
                            thread_host.raster_thread->GetTaskRunner(),
                            thread_host.ui_thread->GetTaskRunner(),
@@ -3112,8 +3113,9 @@ TEST_F(ShellTest, UpdateAssetResolverByTypeAppends) {
 TEST_F(ShellTest, UpdateAssetResolverByTypeNull) {
   ASSERT_FALSE(DartVMRef::IsInstanceRunning());
   Settings settings = CreateSettingsForFixture();
-  ThreadHost thread_host("io.flutter.test." + GetCurrentTestName() + ".",
-                         ThreadHost::Type::Platform);
+  ThreadHost thread_host(ThreadHost::ThreadHostConfig(
+      "io.flutter.test." + GetCurrentTestName() + ".",
+      ThreadHost::Type::Platform));
   auto task_runner = thread_host.platform_thread->GetTaskRunner();
   TaskRunners task_runners("test", task_runner, task_runner, task_runner,
                            task_runner);
@@ -3149,8 +3151,9 @@ TEST_F(ShellTest, UpdateAssetResolverByTypeNull) {
 TEST_F(ShellTest, UpdateAssetResolverByTypeDoesNotReplaceMismatchType) {
   ASSERT_FALSE(DartVMRef::IsInstanceRunning());
   Settings settings = CreateSettingsForFixture();
-  ThreadHost thread_host("io.flutter.test." + GetCurrentTestName() + ".",
-                         ThreadHost::Type::Platform);
+  ThreadHost thread_host(ThreadHost::ThreadHostConfig(
+      "io.flutter.test." + GetCurrentTestName() + ".",
+      ThreadHost::Type::Platform));
   auto task_runner = thread_host.platform_thread->GetTaskRunner();
   TaskRunners task_runners("test", task_runner, task_runner, task_runner,
                            task_runner);