[Impeller] Encode directly to command buffer for Metal.

impeller/renderer/backend/metal/command_buffer_mtl.h

@@ -38,13 +38,6 @@ class CommandBufferMTL final : public CommandBuffer {
   // |CommandBuffer|
   void OnWaitUntilScheduled() override;
 
-  // |CommandBuffer|
-  bool EncodeAndSubmit(const std::shared_ptr<RenderPass>& render_pass) override;
-
-  // |CommandBuffer|
-  bool EncodeAndSubmit(const std::shared_ptr<BlitPass>& blit_ass,
-                       const std::shared_ptr<Allocator>& allocator) override;
-
   // |CommandBuffer|
   std::shared_ptr<RenderPass> OnCreateRenderPass(RenderTarget target) override;
 

impeller/renderer/backend/metal/command_buffer_mtl.mm

@@ -6,7 +6,6 @@
 
 #include "flutter/fml/make_copyable.h"
 #include "flutter/fml/synchronization/semaphore.h"
-#include "flutter/fml/trace_event.h"
 
 #include "impeller/renderer/backend/metal/blit_pass_mtl.h"
 #include "impeller/renderer/backend/metal/compute_pass_mtl.h"
@@ -183,90 +182,6 @@ static bool LogMTLCommandBufferErrorIfPresent(id<MTLCommandBuffer> buffer) {
   return true;
 }
 
-bool CommandBufferMTL::EncodeAndSubmit(
-    const std::shared_ptr<RenderPass>& render_pass) {
-  TRACE_EVENT0("impeller", "CommandBufferMTL::EncodeAndSubmit");
-  if (!IsValid() || !render_pass->IsValid()) {
-    return false;
-  }
-  auto context = context_.lock();
-  if (!context) {
-    return false;
-  }
-  [buffer_ enqueue];
-  auto buffer = buffer_;
-  buffer_ = nil;
-
-#ifdef IMPELLER_DEBUG
-  ContextMTL::Cast(*context).GetGPUTracer()->RecordCmdBuffer(buffer);
-#endif  // IMPELLER_DEBUG
-
-  auto worker_task_runner = ContextMTL::Cast(*context).GetWorkerTaskRunner();
-  auto mtl_render_pass = static_cast<RenderPassMTL*>(render_pass.get());
-
-  // Render command encoder creation has been observed to exceed the stack size
-  // limit for worker threads, and therefore is intentionally constructed on the
-  // raster thread.
-  auto render_command_encoder =
-      [buffer renderCommandEncoderWithDescriptor:mtl_render_pass->desc_];
-  if (!render_command_encoder) {
-    return false;
-  }
-
-  auto task = fml::MakeCopyable(
-      [render_pass, buffer, render_command_encoder, weak_context = context_]() {
-        auto context = weak_context.lock();
-        if (!context) {
-          [render_command_encoder endEncoding];
-          return;
-        }
-
-        auto mtl_render_pass = static_cast<RenderPassMTL*>(render_pass.get());
-        if (!mtl_render_pass->label_.empty()) {
-          [render_command_encoder setLabel:@(mtl_render_pass->label_.c_str())];
-        }
-
-        auto result = mtl_render_pass->EncodeCommands(
-            context->GetResourceAllocator(), render_command_encoder);
-        [render_command_encoder endEncoding];
-        if (result) {
-          [buffer commit];
-        } else {
-          VALIDATION_LOG << "Failed to encode command buffer";
-        }
-      });
-  worker_task_runner->PostTask(task);
-  return true;
-}
-
-bool CommandBufferMTL::EncodeAndSubmit(
-    const std::shared_ptr<BlitPass>& blit_pass,
-    const std::shared_ptr<Allocator>& allocator) {
-  if (!IsValid() || !blit_pass->IsValid()) {
-    return false;
-  }
-  auto context = context_.lock();
-  if (!context) {
-    return false;
-  }
-  [buffer_ enqueue];
-  auto buffer = buffer_;
-  buffer_ = nil;
-
-  auto worker_task_runner = ContextMTL::Cast(*context).GetWorkerTaskRunner();
-  auto task = fml::MakeCopyable(
-      [blit_pass, buffer, weak_context = context_, allocator]() {
-        auto context = weak_context.lock();
-        if (!blit_pass->EncodeCommands(allocator)) {
-          VALIDATION_LOG << "Failed to encode blit pass.";
-          return;
-        }
-        [buffer commit];
-      });
-  worker_task_runner->PostTask(task);
-  return true;
-}
-
 void CommandBufferMTL::OnWaitUntilScheduled() {}
 
 std::shared_ptr<RenderPass> CommandBufferMTL::OnCreateRenderPass(

impeller/renderer/backend/metal/context_mtl.h

@@ -93,8 +93,6 @@ class ContextMTL final : public Context,
 
   id<MTLCommandBuffer> CreateMTLCommandBuffer(const std::string& label) const;
 
-  const std::shared_ptr<fml::ConcurrentTaskRunner> GetWorkerTaskRunner() const;
-
   std::shared_ptr<const fml::SyncSwitch> GetIsGpuDisabledSyncSwitch() const;
 
 #ifdef IMPELLER_DEBUG
@@ -122,7 +120,6 @@ class ContextMTL final : public Context,
   std::shared_ptr<SamplerLibrary> sampler_library_;
   std::shared_ptr<AllocatorMTL> resource_allocator_;
   std::shared_ptr<const Capabilities> device_capabilities_;
-  std::shared_ptr<fml::ConcurrentMessageLoop> raster_message_loop_;
   std::shared_ptr<const fml::SyncSwitch> is_gpu_disabled_sync_switch_;
 #ifdef IMPELLER_DEBUG
   std::shared_ptr<GPUTracerMTL> gpu_tracer_;

impeller/renderer/backend/metal/context_mtl.mm

@@ -88,24 +88,6 @@ static bool DeviceSupportsComputeSubgroups(id<MTLDevice> device) {
   sync_switch_observer_.reset(new SyncSwitchObserver(*this));
   is_gpu_disabled_sync_switch_->AddObserver(sync_switch_observer_.get());
 
-  // Worker task runner.
-  {
-    raster_message_loop_ = fml::ConcurrentMessageLoop::Create(
-        std::min(4u, std::thread::hardware_concurrency()));
-    raster_message_loop_->PostTaskToAllWorkers([]() {
-      // See https://github.com/flutter/flutter/issues/65752
-      // Intentionally opt out of QoS for raster task workloads.
-      [[NSThread currentThread] setThreadPriority:1.0];
-      sched_param param;
-      int policy;
-      pthread_t thread = pthread_self();
-      if (!pthread_getschedparam(thread, &policy, &param)) {
-        param.sched_priority = 50;
-        pthread_setschedparam(thread, policy, &param);
-      }
-    });
-  }
-
   // Setup the shader library.
   {
     if (shader_libraries == nil) {
@@ -330,21 +312,14 @@ new ContextMTL(device, command_queue,
 }
 
 // |Context|
-void ContextMTL::Shutdown() {
-  raster_message_loop_.reset();
-}
+void ContextMTL::Shutdown() {}
 
 #ifdef IMPELLER_DEBUG
 std::shared_ptr<GPUTracerMTL> ContextMTL::GetGPUTracer() const {
   return gpu_tracer_;
 }
 #endif  // IMPELLER_DEBUG
 
-const std::shared_ptr<fml::ConcurrentTaskRunner>
-ContextMTL::GetWorkerTaskRunner() const {
-  return raster_message_loop_->GetTaskRunner();
-}
-
 std::shared_ptr<const fml::SyncSwitch> ContextMTL::GetIsGpuDisabledSyncSwitch()
     const {
   return is_gpu_disabled_sync_switch_;