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

Author: JsouLiang

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"
@@ -23,11 +24,26 @@
 
 namespace fml {
 
-Thread::Thread(const std::string& name) : joined_(false) {
+Thread::ThreadConfig::ThreadConfig(const std::string& name,
+                                   ThreadPriority priority)
+    : thread_name_(name), thread_priority_(priority) {}
+
+void Thread::ThreadConfig::SetCurrentThreadName() {
+  Thread::SetCurrentThreadName(thread_name_);
+}
+
+void Thread::ThreadConfig::SetCurrentThreadPriority() {}
+
+Thread::Thread(const std::string& name)
+    : Thread(ThreadConfig::DefaultConfigure(name)) {}
+
+Thread::Thread(std::unique_ptr<Thread::ThreadConfig> configurer)
+    : thread_config_(std::move(configurer)), joined_(false) {
   fml::AutoResetWaitableEvent latch;
   fml::RefPtr<fml::TaskRunner> runner;
-  thread_ = std::make_unique<std::thread>([&latch, &runner, name]() -> void {
-    SetCurrentThreadName(name);
+  thread_ = std::make_unique<std::thread>([&]() -> void {
+    thread_config_->SetCurrentThreadName();
+    thread_config_->SetCurrentThreadPriority();
     fml::MessageLoop::EnsureInitializedForCurrentThread();
     auto& loop = MessageLoop::GetCurrent();
     runner = loop.GetTaskRunner();

fml/thread.h

@@ -7,6 +7,7 @@
 
 #include <atomic>
 #include <memory>
+#include <string>
 #include <thread>
 
 #include "flutter/fml/macros.h"
@@ -16,18 +17,65 @@ namespace fml {
 
 class Thread {
  public:
-  explicit Thread(const std::string& name = "");
+  // 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 used for setting thread perorities
+  class ThreadConfig {
+   public:
+    explicit ThreadConfig(const std::string& name = "",
+                          ThreadPriority priority = ThreadPriority::NORMAL);
+
+    static std::unique_ptr<ThreadConfig> DefaultConfigure(
+        const std::string& name = "") {
+      return std::make_unique<ThreadConfig>(name);
+    }
+
+    ThreadPriority thread_priority() const { return thread_priority_; }
+
+    const std::string& thread_name() const { return thread_name_; }
+
+    /// Set current thread name
+    virtual void SetCurrentThreadName();
+
+    /// default do nothing, which mean user can use platform api to set priority
+    /// example: iOS might use pthread_qos set thread priority, Android might
+    /// use ::setPriority set thread priority
+    virtual void SetCurrentThreadPriority();
+
+    virtual ~ThreadConfig() = default;
+
+   private:
+    const std::string thread_name_;
+    ThreadPriority thread_priority_;
+  };
+
+  explicit Thread(const std::string& name);
+
+  explicit Thread(std::unique_ptr<ThreadConfig> configurer =
+                      ThreadConfig::DefaultConfigure());
 
   ~Thread();
 
   fml::RefPtr<fml::TaskRunner> GetTaskRunner() const;
 
-  void Join();
-
   static void SetCurrentThreadName(const std::string& name);
 
+  void Join();
+
  private:
   std::unique_ptr<std::thread> thread_;
+  /// ThreadConfigure is used for setting thread configure some like `priority`
+  std::unique_ptr<ThreadConfig> thread_config_;
   fml::RefPtr<fml::TaskRunner> task_runner_;
   std::atomic_bool joined_;
 

fml/thread_unittests.cc

@@ -4,6 +4,8 @@
 
 #include "flutter/fml/thread.h"
 
+#include <pthread.h>
+#include <memory>
 #include "gtest/gtest.h"
 
 TEST(Thread, CanStartAndEnd) {
@@ -24,3 +26,77 @@ TEST(Thread, HasARunningMessageLoop) {
   thread.Join();
   ASSERT_TRUE(done);
 }
+
+TEST(Thread, ThreadNameCreatedWithConfig) {
+  const std::string name = "Thread1";
+  fml::Thread thread(fml::Thread::ThreadConfig::DefaultConfigure(name));
+
+  bool done = false;
+  constexpr int NAMELEN = 8;
+  thread.GetTaskRunner()->PostTask([&done, &name]() {
+    done = true;
+    char thread_name[NAMELEN];
+    pthread_t current_thread = pthread_self();
+    pthread_getname_np(current_thread, thread_name, NAMELEN);
+    ASSERT_EQ(thread_name, name);
+  });
+  thread.Join();
+  ASSERT_TRUE(done);
+}
+
+class MockThreadConfig : public fml::Thread::ThreadConfig {
+ public:
+  using fml::Thread::ThreadConfig::ThreadConfig;
+
+  /// Using iOS platform thread API to configure thread priority
+  void SetCurrentThreadPriority() override {
+    pthread_t tid = pthread_self();
+    struct sched_param param;
+    int policy = SCHED_OTHER;
+    switch (thread_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(std::make_unique<MockThreadConfig>(
+      thread1_name, fml::Thread::ThreadPriority::NORMAL));
+
+  bool done = false;
+  constexpr int NAMELEN = 8;
+  struct sched_param param;
+  int policy;
+  thread.GetTaskRunner()->PostTask([&]() {
+    done = true;
+    char thread_name[NAMELEN];
+    pthread_t current_thread = pthread_self();
+    pthread_getname_np(current_thread, thread_name, NAMELEN);
+    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(std::make_unique<MockThreadConfig>(
+      thread2_name, fml::Thread::ThreadPriority::DISPLAY));
+  thread2.GetTaskRunner()->PostTask([&]() {
+    done = true;
+    char thread_name[NAMELEN];
+    pthread_t current_thread = pthread_self();
+    pthread_getname_np(current_thread, thread_name, NAMELEN);
+    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);
+}

shell/common/thread_host.cc

@@ -4,32 +4,73 @@
 
 #include "flutter/shell/common/thread_host.h"
 
+#include <algorithm>
+#include <memory>
+#include <string>
+#include <utility>
+
 namespace flutter {
 
+std::string ThreadHost::ThreadName(Type type, const std::string& prefix) {
+  switch (type) {
+    case Type::Platform:
+      return prefix + ".platform";
+    case Type::UI:
+      return prefix + ".ui";
+    case Type::IO:
+      return prefix + ".io";
+    case Type::RASTER:
+      return prefix + ".raster";
+    case Type::Profiler:
+      return prefix + ".profiler";
+  }
+}
+
+std::unique_ptr<fml::Thread> ThreadHost::CreateThread(
+    Type type,
+    ThreadHost::ThreadConfig configure) {
+  std::string name = ThreadName(type, name_prefix);
+  if (configure != nullptr) {
+    return std::make_unique<fml::Thread>(std::move(configure));
+  }
+  return std::make_unique<fml::Thread>(
+      fml::Thread::ThreadConfig::DefaultConfigure(name));
+}
+
 ThreadHost::ThreadHost() = default;
 
 ThreadHost::ThreadHost(ThreadHost&&) = default;
 
-ThreadHost::ThreadHost(std::string name_prefix_arg, uint64_t mask)
+ThreadHost::ThreadHost(std::string name_prefix_arg,
+                       uint64_t mask,
+                       ThreadHostConfig configure_host)
     : name_prefix(name_prefix_arg) {
   if (mask & ThreadHost::Type::Platform) {
-    platform_thread = std::make_unique<fml::Thread>(name_prefix + ".platform");
+    platform_thread =
+        CreateThread(ThreadHost::Type::Platform,
+                     std::move(configure_host.platform_configure));
   }
 
   if (mask & ThreadHost::Type::UI) {
-    ui_thread = std::make_unique<fml::Thread>(name_prefix + ".ui");
+    ui_thread = CreateThread(ThreadHost::Type::UI,
+                             std::move(configure_host.ui_configure));
   }
 
   if (mask & ThreadHost::Type::RASTER) {
-    raster_thread = std::make_unique<fml::Thread>(name_prefix + ".raster");
+    raster_thread = CreateThread(ThreadHost::Type::RASTER,
+                                 std::move(configure_host.raster_configure));
   }
 
   if (mask & ThreadHost::Type::IO) {
-    io_thread = std::make_unique<fml::Thread>(name_prefix + ".io");
+    io_thread = CreateThread(ThreadHost::Type::IO,
+                             std::move(configure_host.io_configure));
   }
 
   if (mask & ThreadHost::Type::Profiler) {
-    profiler_thread = std::make_unique<fml::Thread>(name_prefix + ".profiler");
+    profiler_thread =
+        CreateThread(ThreadHost::Type::Profiler,
+                     std::move(configure_host.profiler_configure));
+    ;
   }
 }
 

shell/common/thread_host.h

@@ -6,6 +6,7 @@
 #define FLUTTER_SHELL_COMMON_THREAD_HOST_H_
 
 #include <memory>
+#include <string>
 
 #include "flutter/fml/macros.h"
 #include "flutter/fml/thread.h"
@@ -22,6 +23,19 @@ struct ThreadHost {
     Profiler = 1 << 4,
   };
 
+  static std::string ThreadName(Type type, const std::string& prefix = "");
+
+  using ThreadConfig = std::unique_ptr<fml::Thread::ThreadConfig>;
+  /// The collection of all the thread configures, and we create custom thread
+  /// configure in engine to info the thread.
+  struct ThreadHostConfig {
+    ThreadConfig platform_configure;
+    ThreadConfig ui_configure;
+    ThreadConfig raster_configure;
+    ThreadConfig io_configure;
+    ThreadConfig profiler_configure;
+  };
+
   std::string name_prefix;
   std::unique_ptr<fml::Thread> platform_thread;
   std::unique_ptr<fml::Thread> ui_thread;
@@ -35,9 +49,14 @@ struct ThreadHost {
 
   ThreadHost& operator=(ThreadHost&&) = default;
 
-  ThreadHost(std::string name_prefix, uint64_t type_mask);
+  ThreadHost(std::string name_prefix,
+             uint64_t type_mask,
+             ThreadHostConfig configure_host = ThreadHostConfig());
 
   ~ThreadHost();
+
+ private:
+  std::unique_ptr<fml::Thread> CreateThread(Type type, ThreadConfig configure);
 };
 
 }  // namespace flutter