1250500 - Avoid copying BufferTextureHost if the compositor can sample directly from its memory

Status: RESOLVED FIXED

(Core :: Graphics: Layers, defect)

Description

[Nicolas Silva [:nical]]

BasicCompositor (but not BasicCompositorX11) can efficiently use pixels in memory directly as a source with RGB-style formats, so the copy between BufferTextureHost and DataTextureSource is pretty wasteful.
In this configuration BufferTextureClient/Host should be treated as a texture "without an internal buffer" so that it is used the same way Gralloc and D3D11 textures are used and provide a TextureSource that wraps the BufferTextureHost's memory directly.

Comment 1

[Nicolas Silva [:nical]]

Attachment: Allow buffer textures to be treated as not having an internal buffer.

This patch is implemented on top of bug 1249273.

Comment 2

[Sotaro Ikeda [:sotaro]]

Comment on attachment 8722497 [details] [diff] [review]
Allow buffer textures to be treated as not having an internal buffer.

Review of attachment 8722497 [details] [diff] [review]:
-----------------------------------------------------------------

Naming of HasInternalBuffer seems to become confusing. The flag is changed by compositor type. Can't we rename it to another one like HasIntermediateBuffer?

Comment 3

[Nicolas Silva [:nical]]

(In reply to Sotaro Ikeda [:sotaro] from comment #2)
> Comment on attachment 8722497 [details] [diff] [review]
> Allow buffer textures to be treated as not having an internal buffer.
> 
> Review of attachment 8722497 [details] [diff] [review]:
> -----------------------------------------------------------------
> 
> Naming of HasInternalBuffer seems to become confusing. The flag is changed
> by compositor type. Can't we rename it to another one like
> HasIntermediateBuffer?

HasIntermediateBuffer sounds like a better name, indeed. I filed bug 1250873.

Comment 4

[Sotaro Ikeda [:sotaro]]

Comment on attachment 8722497 [details] [diff] [review]
Allow buffer textures to be treated as not having an internal buffer.

Review of attachment 8722497 [details] [diff] [review]:
-----------------------------------------------------------------

The patch seems good in general:) You might want to clean up codes around "hasInternalBuffer" handling.

::: gfx/layers/BufferTexture.cpp
@@ +96,5 @@
>                            TextureAllocationFlags aAllocFlags,
>                            ISurfaceAllocator* aAllocator)
>  {
> +  // TODO[nical] eeeek
> +  auto fwd = aAllocator ? static_cast<CompositableForwarder*>(aAllocator) : nullptr;

Is there a case that aAllocator is nullptr?

@@ +100,5 @@
> +  auto fwd = aAllocator ? static_cast<CompositableForwarder*>(aAllocator) : nullptr;
> +
> +  bool hasInternalBuffer = fwd
> +                          ? fwd->GetCompositorBackendType() != LayersBackend::LAYERS_BASIC
> +                            || aFormat == gfx::SurfaceFormat::YUV

Do we need this check here? because CreateForYCbCr() should be used for YUV. MemoryTextureData::Create() and ShmemTextureData::Create() have "MOZ_ASSERT(aFormat != gfx::SurfaceFormat::YUV)"

@@ +107,5 @@
> +#ifdef MOZ_WIDGET_GTK
> +  if (!hasInternalBuffer && gfxPlatformGtk::GetPlatform()->UseXRender()) {
> +    hasInternalBuffer = true;
> +  }
> +#endif

It might be better to split the above hasInternalBuffer decision part to a different function to make clear the code.

@@ +418,5 @@
>  MemoryTextureData::Create(gfx::IntSize aSize, gfx::SurfaceFormat aFormat,
>                            gfx::BackendType aMoz2DBackend, TextureFlags aFlags,
>                            TextureAllocationFlags aAllocFlags,
> +                          ISurfaceAllocator*,
> +                          bool aHasInternalBuffer)

It seems like a bit wired to pass aHasInternalBuffer. It could be calculated internally.

::: gfx/layers/ipc/ISurfaceAllocator.cpp
@@ +146,5 @@
>  
>      bufferDesc = shmem;
>    }
>  
> +  *aBuffer = SurfaceDescriptorBuffer(RGBDescriptor(aSize, format, true), bufferDesc);

It seems better to add a comment why it is true.

Comment 5

[Nicolas Silva [:nical]]

New version of the patch coming in a minute.

(In reply to Sotaro Ikeda [:sotaro] from comment #4)
> Comment on attachment 8722497 [details] [diff] [review]
> Allow buffer textures to be treated as not having an internal buffer.
> > +  auto fwd = aAllocator ? static_cast<CompositableForwarder*>(aAllocator) : nullptr;
> 
> Is there a case that aAllocator is nullptr?

Currently only a gtest as far as I know. That test hasn't been any useful so I might just remove it someday but that's another story. 

> 
> @@ +100,5 @@
> > +  auto fwd = aAllocator ? static_cast<CompositableForwarder*>(aAllocator) : nullptr;
> > +
> > +  bool hasInternalBuffer = fwd
> > +                          ? fwd->GetCompositorBackendType() != LayersBackend::LAYERS_BASIC
> > +                            || aFormat == gfx::SurfaceFormat::YUV
> 
> Do we need this check here? because CreateForYCbCr() should be used for YUV.
> MemoryTextureData::Create() and ShmemTextureData::Create() have
> "MOZ_ASSERT(aFormat != gfx::SurfaceFormat::YUV)"

Right, I was being a over-cautious. I remved the check (and moved the whole thing as you suggest in another comment).


> 
> It might be better to split the above hasInternalBuffer decision part to a
> different function to make clear the code.
> 

Updated the patch.

> @@ +418,5 @@
> >  MemoryTextureData::Create(gfx::IntSize aSize, gfx::SurfaceFormat aFormat,
> >                            gfx::BackendType aMoz2DBackend, TextureFlags aFlags,
> >                            TextureAllocationFlags aAllocFlags,
> > +                          ISurfaceAllocator*,
> > +                          bool aHasInternalBuffer)
> 
> It seems like a bit wired to pass aHasInternalBuffer. It could be calculated
> internally.

I was initially trying to not duplicate this logic, but I moved the computation of hasInternalBuffer to its own function as you suggested, and now we call that function from the two constructors.

> >  
> > +  *aBuffer = SurfaceDescriptorBuffer(RGBDescriptor(aSize, format, true), bufferDesc);
> 
> It seems better to add a comment why it is true.

Updated the patch.

Comment 6

[Nicolas Silva [:nical]]

Attachment: Updated patch

Comment 7

[Sotaro Ikeda [:sotaro]]

Comment on attachment 8723497 [details] [diff] [review]
Updated patch

Good!

Comment 8

[Pulsebot]

https://hg.mozilla.org/integration/mozilla-inbound/rev/52e355f34371

Comment 9

[Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)]

https://hg.mozilla.org/mozilla-central/rev/52e355f34371