Closed Bug 695448 (native_droid_panning) Opened 8 years ago Closed 6 years ago

[meta] Panning perf


(Firefox for Android :: General, defect, P1)




Tracking Status
fennec - ---


(Reporter: elan, Assigned: cwiiis)


(Depends on 1 open bug)


(Keywords: meta, Whiteboard: [birch [Product Approved])

Crash Data

No description provided.
OS: Mac OS X → Android
Priority: -- → P1
Hardware: x86 → ARM
Assignee: nobody →
Whiteboard: [birch]
Whiteboard: [birch] → [birch [Product Approved]
Depends on: 696398
Alias: native_droid_panning
Depends on: 699692
Depends on: 699351
Copy and pasting my comment from bug 695449, since it's equally relevant here.

The general design is that we have a Java compositor that renders a large (1024x2048) quad using OpenGL. This is our "display port". It mirrors the e10s separation in XUL Fennec, except that our equivalent of the chrome process is now a Java thread, and the equivalent of the content process is now a Gecko thread. Panning and zooming are in Java and fully asynchronous. The compositor is driven by a "layer client", which is a cached screenshot before Gecko loads and becomes Gecko itself after it's loaded. Thus pan and zoom work before Gecko is up. Gecko renders only in software; there are no GL layers involved on the Gecko side.

This approach mirrors what iOS used to do before version 4 and was chosen due to its combination of simplicity (to get it out the door faster) and good performance. Longer term, the general plan is to use the C++ layer manager decoupled from the rest of Gecko (see Chris Jones' messages to dev.planning for details).

An unresolved question is whether we want panning to be asynchronous or whether we want to sync on Gecko. The benefit of being asynchronous is that panning performance will be higher. The drawbacks are checkerboarding and breaking position:fixed. This approach will work with either choice. Although I'm inclined toward asynchronous panning due to the clear precedent set by other browsers and the excellent performance so far (60 fps for static pages on a range of devices), we should consider both options, because synchronous panning has some advantages and its performance is surprisingly good on fast devices.

Note that I don't believe there are any drawbacks to keeping zooming (this bug) asynchronous, however. Asynchronous zooming is a clear win over synchronous zooming because of the lack of reflows and the use of the GPU for texture scaling. Having position:fixed content "pop in" at the end of a zoom isn't a problem IMHO; most mobile browsers don't bother to redraw during zooming and users are used to that.

The current status is that the physics need work and there are some serious display port/resolution setting/page size issues that prevent this from landing.
Depends on: 700226
No longer blocks: 699303
Depends on: 699303
Blocks: 699939
Blocks: 699940
Depends on: 700403
Duplicate of this bug: 700836
Depends on: 701351
Depends on: 701381
Blocks: 694413
Depends on: 700406
Depends on: 701406
Depends on: 700481
Depends on: 700559
Depends on: 701408
There is no patch here, but the thing that landed was backed while investigating Talos failures.  Now that tests are green again, we will need to reland.
Depends on: 701586
Depends on: 701623
Depends on: 701627
Depends on: 701692
Depends on: 701690
Depends on: 701905
Crash Signature: :
Depends on: 701906
Depends on: 701697
Depends on: 701701
Depends on: 702412
Depends on: 702509
Depends on: 702907
Depends on: 702952
Depends on: 702633
Depends on: 702676
Depends on: 702950
Depends on: 702956
Depends on: 702983
Depends on: 703036
Blocks: 696330
Blocks: 696379
Depends on: 703311
Depends on: 703573
Depends on: 704978
Depends on: 705169
Depends on: 705170
Depends on: 705171
Depends on: 705217
Depends on: 703797
Blocks: 706594
Depends on: 708947
Duplicate of this bug: 708771
tracking-fennec: --- → 11+
blocking-fennec1.0: --- → ?
blocking-fennec1.0: ? → ---
Summary: Panning perf → [meta] Panning perf
Not tracking on metas.
tracking-fennec: 11+ → -
I don't believe this meta bug is useful anymore, closing. For what it's worth, panning performance on fennec is really rather good these days and we track this via our talos tests and eideticker.
Closed: 6 years ago
Resolution: --- → FIXED
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