1501442 - Add method of adding timing information for transaction contents

Status: RESOLVED FIXED

(Core :: Graphics, enhancement, P3)

Description

[Bas Schouten (:bas.schouten)]

As part of a transaction, and therefor as part of a composition, we generally submit a certain amount of visual data to the compositor that was generated at certain points in the past. By being able to associate this contents and the time it was generated with a composition we'd be able to fairly accurately determine the total latency from generation of the event (for example user input), to the result being shown on the screen (i.e. max one frame after composition takes place).

I've discussed this with Markus and I have some ideas on an infrastructure to do this.

Comment 1

[Bas Schouten (:bas.schouten)]

Attachment: Part 1: Add CompositionPayload struct and allow submission with transactions

Comment 2

[Bas Schouten (:bas.schouten)]

Attachment: Part 1: Add CompositionPayload struct and allow submission with transactionsadd-composition-payload v2

Comment 3

[Bas Schouten (:bas.schouten)]

Attachment: Part 1: Add the ability to register CompositionPayloads and forward through transactions v3

Comment 4

[Markus Stange [:mstange]]

Comment on attachment 9019504 [details] [diff] [review]
Part 1: Add the ability to register CompositionPayloads and forward through transactions v3

Review of attachment 9019504 [details] [diff] [review]:
-----------------------------------------------------------------

The approach looks good to me.

::: gfx/layers/Layers.h
@@ +730,5 @@
>  
>    virtual CompositorBridgeChild* GetCompositorBridgeChild() { return nullptr; }
>  
> +  void RegisterPayload(const CompositionPayload& aPayload) { mPayload.AppendElement(aPayload); MOZ_ASSERT(mPayload.Length() < 10000); }
> +  void RegisterPayload(const InfallibleTArray<CompositionPayload>& aPayload) { mPayload.AppendElements(aPayload); MOZ_ASSERT(mPayload.Length() < 10000); }

some long lines here

::: gfx/layers/LayersTypes.h
@@ +472,5 @@
> +  bool operator ==(const CompositionPayload& aOther) const {
> +    return mType == aOther.mType && mTimeStamp == aOther.mTimeStamp;
> +  }
> +  /* The type of payload that is in this composition */
> +  CompositionPayloadType mType; 

end-of-line whitespace

::: gfx/layers/ipc/LayersMessageUtils.h
@@ +666,5 @@
>  {};
>  
> +template <>
> +struct ParamTraits<mozilla::layers::CompositionPayload>
> +  : public PlainOldDataSerializer<mozilla::layers::CompositionPayload>

Let's actually handwrite the serialization for this. That'll give us protection against invalid enum values from compromised content processes, too, and it would make me feel better about correct TimeStamp serialization.

Comment 5

[Bas Schouten (:bas.schouten)]

Attachment: Part 1: Add the ability to register CompositionPayloads and forward through transactions v4

Carrying r+.

Comment 6

[Bas Schouten (:bas.schouten)]

Attachment: Part 1: Add the ability to register CompositionPayloads and forward through transactions v4

Carrying r+.

Comment 7

[Bas Schouten (:bas.schouten)]

Attachment: Part 2: Forward payload from client to host layer managers

WR will need some sort of equivelant of this.

Comment 8

[Bas Schouten (:bas.schouten)]

Attachment: Part 3: Add profiler markers for payload presentation.

This works, although perhaps something more specialized is desirable here where the payload is stored with the Composite trace marker and displayed in the profiler sidebar, I'll let you decide what you want to do here Markus, if you provide me with pointers I can implement something better.

Comment 9

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/4c1fade7ceeb
Part 1: Add CompositionPayload type and allow submitting it as part of a transaction. r=mstange
https://hg.mozilla.org/integration/mozilla-inbound/rev/76070b4feec3
Part 2: Propagate composition payload from clients to host. r=rhunt
https://hg.mozilla.org/integration/mozilla-inbound/rev/a123204b6b0d
Part 3: Add profiler markers for payload presentarion. r=mstange

Comment 10

[Daniel Varga [:dvarga]]

https://hg.mozilla.org/mozilla-central/rev/4c1fade7ceeb
https://hg.mozilla.org/mozilla-central/rev/76070b4feec3
https://hg.mozilla.org/mozilla-central/rev/a123204b6b0d