[Impeller] Add interface for submitting multiple command buffers at once. #50139

jonahwilliams · 2024-01-29T16:00:21Z

The Impeller Vulkan backend benefits from batching submission to the vk graphics queue. Managing this automatically is non-trivial and adds surprising/fragile thread based behavior, see: #49870

Instead, introduce an impeller::CommandQueue object that command buffers must be submitted to in lieu of CommandBuffer->Submit, which has been made private.

TLDR

old

buffer->Submit();

new

context.GetQueue()->Submit({buffer});

The Metal and GLES implementations internally just call the private CommandBuffer->Submit, though there may be future opportunities to simplify here. The Vulkan implementation is where the meat is.

Aiks takes advantage of this by storing all command buffers on the aiks context while rendering a frame, and then performing one submit in aiks_context render. I don't think this will introduce any thread safety problems, as we don't guarantee much about aiks context - nor do we use it in a multithreaded context as far as I know.

Other tasks such as image upload still just directly submit their command buffers via the queue.

Fixes flutter/flutter#141123

chinmaygarde

Approach looks good.

chinmaygarde · 2024-01-29T18:16:01Z

impeller/renderer/backend/vulkan/graphics_queue_vk.h

+                     const CompletionCallback& callback = {}) override;
+
+ private:
+  std::weak_ptr<ContextVK> context_;


Whatever FML_DISALLOW_COPY_ASSIGN_AND_MOVE expands to. Not having to depend on the base class for deletes avoid potential expensive copies in case that interface changes but we put an expensive to copy ivar here.

chinmaygarde · 2024-01-29T18:19:43Z

impeller/renderer/context.h

@@ -163,6 +162,9 @@ class Context {
  ///
  virtual std::shared_ptr<CommandBuffer> CreateCommandBuffer() const = 0;

+  /// @brief Return the graphics queue for submitting command buffers.
+  virtual const std::shared_ptr<GraphicsQueue>& GetQueue() const = 0;


GetGraphicsQueue?

Pending resolution about the comment later about the class name.

Conflicts with context_vk.h GetGraphicsQueue for the QueueVK class.

chinmaygarde · 2024-01-29T18:21:13Z

impeller/renderer/graphics_queue.h

+ public:
+  using CompletionCallback = std::function<void(CommandBuffer::Status)>;
+
+  GraphicsQueue() = default;


chinmaygarde · 2024-01-29T18:21:57Z

impeller/renderer/graphics_queue.h

+  ///        The order of the provided buffers determines the ordering in which
+  ///        they are submitted.
+  ///
+  ///        Optionally accepts a ccallback that will fire with an updated


"callback" misspelled.

chinmaygarde · 2024-01-29T18:24:03Z

impeller/renderer/graphics_queue.h

+
+/// @brief An interface for submitting command buffers to the GPU for
+///        encoding and execution.
+class GraphicsQueue {


From the name, I was expecting this to be akin to the graphics vs compute vs transfer queues. But this doesn't seem to be the case. How about just calling this CommandQueue instead?

CommandQueue SGTM, solves naming problems too.

Renamed, other stuff WIP

chinmaygarde · 2024-01-29T18:32:39Z

impeller/renderer/graphics_queue.h

+  ///        they are submitted.
+  ///
+  ///        Optionally accepts a ccallback that will fire with an updated
+  ///        status based on encoding state. Only the Metal and Vulkan backend


Perhaps a better way of putting this would be "The status only indicates if the command buffer was successfully submitted. Successful completion of the command buffer can only be checked in the completion callback.".

So, if the status is not OK, can the caller expect a completion callback invocation? Otherwise they might have to perform cleanup themselves if the callback is dropped on the floor.

Hmm, a better interface might be to guarantee that the callback always gets invoked but with CommandBuffer::Status::kError in case of failure to submit as well. This function can return void. This avoids burden on the caller to check for error and invoke the callback themselves in case the callback has cleanup they want to perform.

That change would make it much more difficult to detect immediate submission errors

chinmaygarde · 2024-01-29T18:41:20Z

impeller/renderer/backend/vulkan/graphics_queue_vk.cc

+  if (!added_fence) {
+    return fml::Status(fml::StatusCode::kCancelled, "Failed to add fence.");
+  }
+  fail_callback = false;


fml::ScopedCleanupClosure has a Release call that you can invoke instead of tracking the success case in a var.

chinmaygarde · 2024-01-29T18:43:13Z

impeller/renderer/backend/vulkan/graphics_queue_vk.cc

+fml::Status GraphicsQueueVK::Submit(
+    const std::vector<std::shared_ptr<CommandBuffer>>& buffers,
+    const CompletionCallback& callback) {
+  if (buffers.empty()) {


Don't know what if the "you'll always get the callback no matter what" behavior is, asked for clarification in the headerdoc. But if it is the case, you might need a success callback invocation here.

chinmaygarde · 2024-01-29T18:44:49Z

impeller/renderer/backend/vulkan/graphics_queue_vk.cc

+  }
+
+  vk::SubmitInfo submit_info;
+  submit_info.setCommandBuffers(vk_buffers);


Good stuff.

chinmaygarde · 2024-01-29T18:48:27Z

impeller/renderer/backend/vulkan/graphics_queue_vk.cc

+      [callback, tracked_objects = std::move(tracked_objects)]() mutable {
+        // Ensure tracked objects are destructed before calling any final
+        // callbacks.
+        for (auto& tracked_object : tracked_objects) {


tracked_objects.clear() is the same as individually resetting the items in a loop.

bdero · 2024-01-29T20:58:23Z

lib/gpu/command_buffer.cc

@@ -35,15 +37,18 @@ bool CommandBuffer::Submit() {
  for (auto& encodable : encodables_) {
    encodable->EncodeCommands();
  }
-  return command_buffer_->SubmitCommands();
+
+  return context_->GetCommandQueue()->Submit({command_buffer_}).ok();


So I'll just need to do this in a raster task to keep it safe, right?

this has the exact same threading guarantees as CommandBuffer->Submit. Its the AiksContext batching that is not necessarily thread safe.

jonahwilliams · 2024-01-29T23:07:12Z

I'm not quite sure how to fix this compilation error:

[7460/7463] LINK ./ui_unittests
FAILED: ui_unittests exe.unstripped/ui_unittests 
/b/s/w/ir/cache/goma/client/gomacc ../../buildtools/linux-x64/clang/bin/clang++ -Wl,--fatal-warnings -m64 -fPIC -Wl,-z,noexecstack -Wl,-z,now -Wl,-z,relro -Wl,-z,defs -pthread -Wl,--undefined-version --sysroot=../../build/linux/debian_sid_amd64-sysroot  -Wl,-O2 -Wl,--gc-sections -Wl,--as-needed -Wl,-rpath=\$ORIGIN/ -Wl,-rpath-link= -Wl,--disable-new-dtags -Wl,--dynamic-list=../../flutter/common/exported_symbols.sym -rdynamic  -o ./exe.unstripped/ui_unittests -Wl,--build-id=sha1 -Wl,--start-group @./ui_unittests.rsp  -Wl,--end-group  -ldl -lgtk-3 -lgdk-3 -lpangocairo-1.0 -lpango-1.0 -latk-1.0 -lcairo-gobject -lcairo -lgdk_pixbuf-2.0 -lgio-2.0 -lgobject-2.0 -lglib-2.0 -lpthread  && ../../buildtools/linux-x64/clang/bin/llvm-objcopy --strip-all ./exe.unstripped/ui_unittests ./ui_unittests
ld.lld: error: undefined symbol: std::_fl::shared_ptr<impeller::CommandQueue>::~shared_ptr[abi:v15000]()
>>> referenced by image_encoding_unittests.cc
>>>               obj/flutter/lib/ui/painting/ui_unittests.image_encoding_unittests.o:(std::_fl::__function::__func<flutter::testing::(anonymous namespace)::MakeConvertDlImageToSkImageContext(std::_fl::vector<unsigned char, std::_fl::allocator<unsigned char>>&)::$_0, std::_fl::allocator<flutter::testing::(anonymous namespace)::MakeConvertDlImageToSkImageContext(std::_fl::vector<unsigned char, std::_fl::allocator<unsigned char>>&)::$_0>, std::_fl::shared_ptr<impeller::CommandQueue> const& ()>::operator()())
clang++: error: linker command failed with exit code 1 (use -v to see invocation)
ninja: build stopped: subcommand failed.

jonahwilliams · 2024-01-30T07:02:08Z

this time its gonna work, I can feel it

…ffers at once. (flutter/engine#50139)

…142515) flutter/engine@438e9b4...0e586d1 2024-01-30 jonahwilliams@google.com [Impeller] Add interface for submitting multiple command buffers at once. (flutter/engine#50139) 2024-01-30 49699333+dependabot[bot]@users.noreply.github.com Bump actions/upload-artifact from 4.1.0 to 4.3.0 (flutter/engine#50165) 2024-01-30 skia-flutter-autoroll@skia.org Roll Skia from 083c1a4d9767 to 4e992fb3a9db (1 revision) (flutter/engine#50164) 2024-01-30 mbrase@google.com Use structured logging on Fuchsia (flutter/engine#49918) If this roll has caused a breakage, revert this CL and stop the roller using the controls here: https://autoroll.skia.org/r/flutter-engine-flutter-autoroll Please CC matanl@google.com,rmistry@google.com,zra@google.com on the revert to ensure that a human is aware of the problem. To file a bug in Flutter: https://github.com/flutter/flutter/issues/new/choose To report a problem with the AutoRoller itself, please file a bug: https://issues.skia.org/issues/new?component=1389291&template=1850622 Documentation for the AutoRoller is here: https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md

jonahwilliams · 2024-01-30T17:10:52Z

This is causing the animated backdrop blur integration test to fail on iOS in the framework. Will investigate.

…ers at once. (#50139)" This reverts commit 0e586d1.

…fers at once." (#50174) Reverts #50139 Initiated by: jonahwilliams This change reverts the following previous change: Original Description: The Impeller Vulkan backend benefits from batching submission to the vk graphics queue. Managing this automatically is non-trivial and adds surprising/fragile thread based behavior, see: #49870 Instead, introduce an impeller::CommandQueue object that command buffers must be submitted to in lieu of CommandBuffer->Submit, which has been made private. TLDR old ```c++ buffer->Submit(); ``` new ```c++ context.GetQueue()->Submit({buffer}); ``` The Metal and GLES implementations internally just call the private CommandBuffer->Submit, though there may be future opportunities to simplify here. The Vulkan implementation is where the meat is. Aiks takes advantage of this by storing all command buffers on the aiks context while rendering a frame, and then performing one submit in aiks_context render. I don't think this will introduce any thread safety problems, as we don't guarantee much about aiks context - nor do we use it in a multithreaded context as far as I know. Other tasks such as image upload still just directly submit their command buffers via the queue. Fixes flutter/flutter#141123

…ffers at once. (flutter/engine#50139)

…142543) flutter/engine@438e9b4...0e4342c 2024-01-30 98614782+auto-submit[bot]@users.noreply.github.com Reverts "[Impeller] Add interface for submitting multiple command buffers at once." (flutter/engine#50174) 2024-01-30 skia-flutter-autoroll@skia.org Roll Skia from a3d46fac53be to 7df4d35e11cf (3 revisions) (flutter/engine#50173) 2024-01-30 skia-flutter-autoroll@skia.org Roll Skia from c2fada52fdc4 to a3d46fac53be (2 revisions) (flutter/engine#50171) 2024-01-30 skia-flutter-autoroll@skia.org Roll Skia from 7dc9ba2e8c90 to c2fada52fdc4 (1 revision) (flutter/engine#50170) 2024-01-30 skia-flutter-autoroll@skia.org Roll Skia from 1c0eae94fc09 to 7dc9ba2e8c90 (1 revision) (flutter/engine#50169) 2024-01-30 skia-flutter-autoroll@skia.org Roll Skia from 4e992fb3a9db to 1c0eae94fc09 (3 revisions) (flutter/engine#50167) 2024-01-30 skia-flutter-autoroll@skia.org Roll Fuchsia Linux SDK from Hqi_x_A9lYsY58VSn... to Z-xFM2ILZJw22eU8q... (flutter/engine#50166) 2024-01-30 jonahwilliams@google.com [Impeller] Add interface for submitting multiple command buffers at once. (flutter/engine#50139) 2024-01-30 49699333+dependabot[bot]@users.noreply.github.com Bump actions/upload-artifact from 4.1.0 to 4.3.0 (flutter/engine#50165) 2024-01-30 skia-flutter-autoroll@skia.org Roll Skia from 083c1a4d9767 to 4e992fb3a9db (1 revision) (flutter/engine#50164) 2024-01-30 mbrase@google.com Use structured logging on Fuchsia (flutter/engine#49918) Also rolling transitive DEPS: fuchsia/sdk/core/linux-amd64 from Hqi_x_A9lYsY to Z-xFM2ILZJw2 If this roll has caused a breakage, revert this CL and stop the roller using the controls here: https://autoroll.skia.org/r/flutter-engine-flutter-autoroll Please CC matanl@google.com,rmistry@google.com,zra@google.com on the revert to ensure that a human is aware of the problem. To file a bug in Flutter: https://github.com/flutter/flutter/issues/new/choose To report a problem with the AutoRoller itself, please file a bug: https://issues.skia.org/issues/new?component=1389291&template=1850622 Documentation for the AutoRoller is here: https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md

…ers at once. (#50180) Reland of: #50139 Metal does not seem to like it when we collect 50+ command buffers at once. Adjust the aiks context logic to regularly flush the cmd buffers.

[Impeller] introduce queue abstraction to allow aiks to batch submit.

4c362b2

github-actions bot added platform-android e: impeller labels Jan 29, 2024

++

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jonahwilliams force-pushed the queue_based_submitter branch from 84d79a6 to f6f72f5 Compare January 29, 2024 16:15

jonahwilliams added 4 commits January 29, 2024 10:08

mock and license fixes.

2ac8d59

add missing include.

7ff7cab

++

0a92952

Add dtor.

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chinmaygarde reviewed Jan 29, 2024

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jonahwilliams added 2 commits January 29, 2024 12:13

rename to command queue.

1eac589

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48220a9

bdero reviewed Jan 29, 2024

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jonahwilliams added 4 commits January 29, 2024 13:06

Remove initializer list.

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fix image decoder unittests.

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fix licenses.

e591b05

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jonahwilliams added 2 commits January 29, 2024 18:29

thanks Jason.

559016a

fix mocks

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jonahwilliams mentioned this pull request Jan 30, 2024

[Impeller] Join Vulkan queue submissions. #49870

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jonahwilliams added 7 commits January 29, 2024 20:15

fix testing.

355bb94

++

4fb5548

++

f7b7306

maybe this works on CI.

b4d81fb

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f33a4b6

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2c82ff4

remove uh oh

66f9d96

Merge branch 'main' into queue_based_submitter

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…ers at once. (#50139)" This reverts commit 0e586d1.

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Reverts "[Impeller] Add interface for submitting multiple command buffers at once." #50174

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[Impeller] Reland: add interface for submitting multiple command buffers at once. #50180

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[Impeller] Add interface for submitting multiple command buffers at once. #50139

[Impeller] Add interface for submitting multiple command buffers at once. #50139

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