1297612 - [E10S A11y] Various operations in Gmail noticeably slower with E10S on

Status: RESOLVED WORKSFORME

(Core :: Disability Access APIs, defect)

Description

[Marco Zehe (:MarcoZ)]

STR:
1. Force-enable E10S.
2. With NVDA on, start Nightly and log into Gmail. Preferably, because of bug 1297549, you just restart it with the Gmail tab auto-loading.
3. NVDA will switch to its focus mode, which means the virtual buffer is off. You'll land in the table of conversations.
4. Arrow up and down through the conversations.
5. Now, compare that to a build with E10S off.

Result: With E10S off, focus changes are instantaneously announced. With E10S on, there is at least a half second delay before the new item is spoken.

Consistently reproducible on my Surface Book with Windows 10 SR1 Pro X64.

Comment 1

[Marco Zehe (:MarcoZ)]

CC'ing Jamie, too.

Comment 2

[Marco Zehe (:MarcoZ)]

Note that this bug has changed slightly in the 2016-09-20 Nightly build, which has a fix for bug 1297549.

1. If, when starting Nightly in e10s mode, Gmail is the first tab, NVDA's focus mode gets enabled straight away, without first going into virtual buffer mode.
2. At this point, I found focus shifting to be extremely slow. Like two seconds between message threads where normally the reaction is instantaneous.
3. Press tab to move out of the messages, which invokes virtual buffer.
4. Shift-tab back and arrow up and down again.

Result: Now, the reaction is very snappy.

I'll leave this open, but again, notice that this problem is no longer permanent, but tied to a very specific condition, and then hits pretty badly.

Comment 3

[Marco Zehe (:MarcoZ)]

This bug has changed again with the 2016-10-06 build, which contains the fix for bug 1304449. Now, focus shifting between the message threads is OK, but opening a message takes a significant amount of time, while a build with E10S off on the same connection is very snappy. Half a second after pressing Enter on a thread with E10S off, about 3 to 5 seconds with E10S on, before NVDA starts reading the message thread.

Also, when returning from the message thread to the list of threads, NVDA's focus mode is no longer consistently switching back to focus mode, and it again takes significantly longer with E10S on.

Comment 4

[Jim Mathies [:jimm]]

Hey Marco, are you still seeing these gmail issues?

Comment 5

[Marco Zehe (:MarcoZ)]

Very occasionally, but it's now a more consistent general performance degradation when screen readers load documents in E10S mode vs. non-E10S mode. That very specific lag has disappeared.

Comment 6

[Marco Zehe (:MarcoZ)]

This is still there when E10S is turned on in 54. Nominating for tracking, hoping that the SmartProxy work will mittigate this somewhat, but need a working build before I can give any views on that.

Note that this is far broader than just Gmail, like also happening on FaceBook and other sites, so it's most likely a11y+e10s related rather than platform-rel. Suggesting to take this off the platform-rel radar, but leaving that up to the powers that be.

Comment 7

[David Bolter [:davidb] (NeedInfo me for attention)]

Jim, talking to Marco this certainly sounds like an aes+ -- what do you think?

(Not sure if our talos perf tests capture this; maybe)

Comment 8

[(No longer employed by Mozilla) Aaron Klotz]

I think we need to reevaluate this when the handler lands.

Comment 9

[Jim Mathies [:jimm]]

perf is acceptable now.