1367665 - [Input Latency] Firefox is 31% (53 ms) slower than Chrome in case GMail - Open Email

Status: RESOLVED INVALID

(Core :: JavaScript Engine, defect, P3)

Description

[Walter Chen[:ypwalter][:wachen]]

STR:
1. Open Gmail in logged in state.
2. Mouse click the first email in the inbox

Reports: https://goo.gl/pdMRw9
Notes: https://docs.google.com/spreadsheets/d/1MsTK1FW88wuLd25A18HG2KqpjYJnvrxGM9a6MeZp35w/edit#gid=256706414

Firefox Profile and Chrome Tracing will be attached in the following.

Comment 1

[Walter Chen[:ypwalter][:wachen]]

Firefox Profile:
https://perfht.ml/2qmxr0I
Chrome Tracing:
https://goo.gl/gV2ExC

Comment 2

[Jeff Muizelaar [:jrmuizel]]

This looks like it's dominated by big blocks of js running.

Comment 3

[MarkYen]

Short Gecko Profile(cover only Input Lantency action):
https://perfht.ml/2rizrv2

Comment 5

[Bobby Chien]

Catalin, could you help to profile this bug? Thanks.

Comment 6

[Cătălin Badea (:catalinb)]

I think someone that's more experienced with the js engine should have a look at this.

The click event takes, 30ms, running js with nothing obvious showing up in the profiler.

After the click event we execute a huge chunk of js ~400ms.
https://perf-html.io/public/2152988fd4471adbdfafdea0d6e9d5a0d4324b5c/calltree/?hiddenThreads=&range=3.9053_4.8623&thread=5&threadOrder=0-2-3-5-1-4

The stack looks to be missing the frames calling js::RunScript. On a local profile this is executed inside a promise microtask checkpoint.

Local profile: https://perf-html.io/public/cf321decb79c072d3994fa56142fe2630ee2fb5c/calltree/?hiddenThreads=&range=2.4113_2.7467&thread=4&threadOrder=0-2-3-4-1

Next, we spend time in nsRefreshDriver::DoTick, but this doesn't look out of the ordinary.
https://perf-html.io/public/2152988fd4471adbdfafdea0d6e9d5a0d4324b5c/calltree/?hiddenThreads=&range=5.0565_5.1672&thread=5&threadOrder=0-2-3-5-1-4

Comment 7

[Bobby Chien]

tracking under qf.

Comment 8

[Naveed Ihsanullah [:naveed]]

Ted can you please profile this

Comment 9

[Mike Conley (:mconley) (:⚙️)]

The new Gmail UI is going to come along and probably invalidate most if not all of the analysis in here. I'm going to close this as INVALID (or maybe I should use INCOMPLETE - I don't really know), and if the new Gmail ends up being non-performant in the same way, we should file a new bug I think.