Adds flush to metal screenshotter.#183758
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This pull request adds a GPU flush to the Metal screenshotter before capturing a screenshot. This is achieved by submitting an empty command buffer and waiting for its completion, which should prevent capturing incomplete frames. The change also refactors how the Context is obtained, now consistently using the one from AiksContext.
| if (auto cmd_buffer = context->CreateCommandBuffer()) { | ||
| if (context->GetCommandQueue() | ||
| ->Submit({cmd_buffer}, | ||
| [&latch](CommandBuffer::Status status) { | ||
| FML_CHECK(status == CommandBuffer::Status::kCompleted); | ||
| latch.Signal(); | ||
| }) | ||
| .ok()) { | ||
| latch.Wait(); | ||
| } | ||
| } |
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The current implementation silently ignores failures when creating or submitting the flush command buffer. If CreateCommandBuffer returns nullptr or Submit fails, the code proceeds to take a screenshot without waiting for GPU commands to finish. This could lead to capturing an incomplete or incorrect frame, causing flaky tests.
It's better to explicitly handle these failures. Using FML_CHECK would make the failure obvious and prevent proceeding with a likely incorrect state.
if (auto cmd_buffer = context->CreateCommandBuffer()) {
if (context->GetCommandQueue()
->Submit({cmd_buffer},
[&latch](CommandBuffer::Status status) {
FML_CHECK(status == CommandBuffer::Status::kCompleted);
latch.Signal();
})
.ok()) {
latch.Wait();
} else {
FML_CHECK(false && "Failed to submit flush command buffer.");
}
} else {
FML_CHECK(false && "Failed to create command buffer for flush.");
}
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Any value in the bot's suggestion? I'm guessing it's pretty hard to get here if there is no command queue or if it will fail to Submit?
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It would turn a failed test into a crash. I don't know that that is necessary. It doesn't seem that likely, probably best to just print something out?
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return nullptr and let the caller fail the test?
That would require too much re-plumbing throughout the unit and golden tests...
|
Golden file changes have been found for this pull request. Click here to view and triage (e.g. because this is an intentional change). If you are still iterating on this change and are not ready to resolve the images on the Flutter Gold dashboard, consider marking this PR as a draft pull request above. You will still be able to view image results on the dashboard, commenting will be silenced, and the check will not try to resolve itself until marked ready for review. For more guidance, visit Writing a golden file test for Reviewers: Read the Tree Hygiene page and make sure this patch meets those guidelines before LGTMing. |
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LGTM with questions that are probably moot...
| AiksContext& aiks_context, | ||
| const std::shared_ptr<Texture> texture) { | ||
| @autoreleasepool { | ||
| std::shared_ptr<Context> context = aiks_context.GetContext(); |
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I'll take your word that this is the same as the context returned from the playground (where it used to be fetched from below).
| if (auto cmd_buffer = context->CreateCommandBuffer()) { | ||
| if (context->GetCommandQueue() | ||
| ->Submit({cmd_buffer}, | ||
| [&latch](CommandBuffer::Status status) { | ||
| FML_CHECK(status == CommandBuffer::Status::kCompleted); | ||
| latch.Signal(); | ||
| }) | ||
| .ok()) { | ||
| latch.Wait(); | ||
| } | ||
| } |
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Any value in the bot's suggestion? I'm guessing it's pretty hard to get here if there is no command queue or if it will fail to Submit?
|
Oh wow, look at the golden changes. There was a test before that would reliably create a magenta image it seems. I wonder how that happened. |
|
It looks like the new flushes caught an old test that was failing to return an answer every time it ran. (Oops, comments crossed in the ether...) |
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It's a huge downscale of a huge saveLayer content. It probably took a long time to run and didn't return an answer before we pushed the golden result... |
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2 participants
fixes: #183746
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