[engine] move asset mapping copy to background thread #39918

jonahwilliams · 2023-02-27T19:36:03Z

Fixes flutter/flutter#121525
Fixes flutter/flutter#121351

Move asset open/copy to a background thread

See timeline trace:

flutter-dashboard · 2023-02-27T19:36:07Z

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chinmaygarde · 2023-02-28T04:08:42Z

lib/ui/painting/immutable_buffer.cc


-  auto size = data->GetSize();
-  const void* bytes = static_cast<const void*>(data->GetMapping());
-  auto sk_data = MakeSkDataWithCopy(bytes, size);


I was scratching my head about what was being decompressed and where. Is this copy doing the decompression via faults?

oh, I don't know why I called this decompression.

We need to open the file and then copy it into an SkData (due to potential lack of thread-safeness of asset mappings_.

dnfield · 2023-02-28T05:37:05Z

lib/ui/painting/immutable_buffer.cc

+          // -1 is used as a sentinel that the file could not be opened.
+          tonic::DartInvoke(buffer_callback->Get(), {tonic::ToDart(-1)});


You could also just use Dart_Null() to avoid a sentinel and the tonic conversion.

Then the receiving callback would have to be nullable and its still a sentinel value.

dnfield · 2023-03-01T04:48:14Z

lib/ui/painting/immutable_buffer.cc

+        tonic::DartInvoke(buffer_callback->Get(), {tonic::ToDart(buffer_size)});
+      });
+
+  dart_state->GetConcurrentTaskRunner()->PostTask(


nit: this isn't the IO thread either, this is the worker pool.

There should really be some kind of test for this. https://github.com/flutter/engine/pull/29016/files was a similar attempt that had a test.

will take a look at this

is there perhaps a better way to do this without mocking out so much functionality? I don't actually care that its done on a background worker either, just that its non blocking.

I spent some more time looking at this and I'm still scratching my head a bit. I can't mock/override things on the engine to implement this easily since immutable buffer itself is mostly using UIDartState.

@dnfield any ideas?

I thought you could basically use the test from the PR I linked.

It doesn't assert the copy is happening on the worker thread, but it does assert that assets are opened on the worker thread.

I could not, that PR predates us moving all of this logic to immutable_buffer

chinmaygarde · 2023-03-02T21:09:18Z

From Triage: Only the AAssetManager backed asset managers have thread safety issues. We should just ask the managers about their thread safety characteristics so that we can elide the copy where we can. I suspect everything except Android can.

jonahwilliams · 2023-03-07T19:31:18Z

tested!

jonahwilliams · 2023-03-07T20:42:20Z

tests worked locally but I was not building unopt, will double check again

dnfield · 2023-03-07T23:40:57Z

shell/common/shell_unittests.cc

+  EXPECT_EQ(leaked_resolver->mapping_requests[0], "DoesNotExist");
+
+  PlatformViewNotifyDestroyed(shell.get());
+  DestroyShell(std::move(shell));


I think you want DestroyShell(std::move(shell), task_runners) - the unopt crash is suggesting the shell is getting destroyed on the wrong thread.

Thank you for saving me hours of debugging

…ne into move_decompress_to_io

…ter/engine#39918)

This reverts commit 7684aa0.

…" (#40147) Revert "[engine] move asset mapping copy to background thread"

…ter/engine#39918)

jonahwilliams added 2 commits February 27, 2023 11:15

[engine] move asset mapping decompression to IO thread

ab5d7be

acquire on UI thread

4bb1999

jonahwilliams requested a review from dnfield February 27, 2023 19:36

flutter-dashboard bot added the needs tests label Feb 27, 2023

fix error handling

3fcc0bd

chinmaygarde reviewed Feb 28, 2023

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jonahwilliams changed the title ~~[engine] move asset decompression to IO thread~~ [engine] move asset mapping copy to IO thread Feb 28, 2023

jonahwilliams requested a review from chinmaygarde February 28, 2023 19:50

dnfield reviewed Mar 1, 2023

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jonahwilliams changed the title ~~[engine] move asset mapping copy to IO thread~~ [engine] move asset mapping copy to background thread Mar 1, 2023

jonahwilliams added 2 commits March 7, 2023 10:29

try a shell test

6505195

fix test

33a7117

jonahwilliams requested a review from dnfield March 7, 2023 18:57

Merge branch 'main' into move_decompress_to_io

36dcc82

jonahwilliams removed the needs tests label Mar 7, 2023

Update shell_unittests.cc

efe5617

dnfield reviewed Mar 7, 2023

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dnfield approved these changes Mar 7, 2023

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jonahwilliams added 2 commits March 7, 2023 15:44

fix shell destruction thread

ba10197

Merge branch 'move_decompress_to_io' of github.com:jonahwilliams/engi…

661ee40

…ne into move_decompress_to_io

jonahwilliams added the autosubmit Merge PR when tree becomes green via auto submit App label Mar 8, 2023

auto-submit bot merged commit 7684aa0 into flutter:main Mar 8, 2023

engine-flutter-autoroll mentioned this pull request Mar 8, 2023

Roll Flutter Engine from ab28c582f4f4 to 7684aa0e9847 (2 revisions) flutter/flutter#122156

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7684aa0e9 [engine] move asset mapping copy to background thread (flut…

c37b475

…ter/engine#39918)

engine-flutter-autoroll mentioned this pull request Mar 8, 2023

Roll Flutter Engine from ab28c582f4f4 to 694a14ca6e15 (3 revisions) flutter/flutter#122158

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7684aa0e9 [engine] move asset mapping copy to background thread (flut…

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…ter/engine#39918)

zanderso added a commit that referenced this pull request Mar 8, 2023

Revert "[engine] move asset mapping copy to background thread (#39918)"

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This reverts commit 7684aa0.

zanderso mentioned this pull request Mar 8, 2023

Revert "[engine] move asset mapping copy to background thread" #40147

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Revert "[engine] move asset mapping copy to background thread (#39918)…

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…" (#40147) Revert "[engine] move asset mapping copy to background thread"

engine-flutter-autoroll mentioned this pull request Mar 8, 2023

Roll Flutter Engine from ab28c582f4f4 to 431df2e9a8c1 (14 revisions) flutter/flutter#122228

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7684aa0e9 [engine] move asset mapping copy to background thread (flut…

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…ter/engine#39918)

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Roll Flutter Engine from ab28c582f4f4 to 098fd5884e55 (15 revisions) flutter/flutter#122234

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7684aa0e9 [engine] move asset mapping copy to background thread (flut…

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…ter/engine#39918)

jonahwilliams mentioned this pull request Mar 9, 2023

Reland: Move asset opening to background thread, fix dart persistent value destruction #40183

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HansMuller mentioned this pull request Mar 16, 2023

Flutter Framework Team: Notable Commits flutter/flutter#121415

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[engine] move asset mapping copy to background thread #39918

[engine] move asset mapping copy to background thread #39918

jonahwilliams commented Feb 27, 2023 •

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flutter-dashboard bot commented Feb 27, 2023

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dnfield Mar 7, 2023

jonahwilliams Mar 7, 2023

		// -1 is used as a sentinel that the file could not be opened.
		tonic::DartInvoke(buffer_callback->Get(), {tonic::ToDart(-1)});

[engine] move asset mapping copy to background thread #39918

[engine] move asset mapping copy to background thread #39918

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jonahwilliams commented Feb 27, 2023 •

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