Firefox 56.0.1 performance problems with a featured extension

Firefox Development
#1

Test environment

https://addons.mozilla.org/addon/enhancer-for-youtube/

  • version 2.0.43
  • FEATURED by Mozilla.

HP EliteBook 8570p notebook

  • 16 GB memory
  • four ACPI CPUs
  • KDE Plasma 5.11.0
  • KDE Frameworks 5.38.0
  • Qt 5.7.1
  • KWin
  • XRender
  • more than a thousand tabs (1,076 before the tab to the YouTube video is opened by a click in Thunderbird)
  • fewer than twenty tabs loaded
  • an unusual mix of extensions, but nothing that I associate with performance problems such as those seen in the screen recording above.
[grahamperrin@momh167-gjp4-hpelitebook8570p-freebsd] ~% date ; uname -v
Sun 15 Oct 2017 08:01:33 BST
FreeBSD 12.0-CURRENT #0 r320869: Mon Jul 10 13:57:55 UTC 2017     root@releng3.nyi.freebsd.org:/usr/obj/usr/src/sys/GENERIC 
[grahamperrin@momh167-gjp4-hpelitebook8570p-freebsd] ~% pkg info firefox | grep -i version
Version        : 56.0.1,1
[grahamperrin@momh167-gjp4-hpelitebook8570p-freebsd] ~%
  • Tier-3

Related

#2

tl;dr

Firefox performance problems involving the featured extension are observed not only when first attempting to view a YouTube video. In addition:

  • there are extraordinary delays when the extension is simply enabled (after launching Firefox with the extension disabled)

– most noticeable with my ‘everyday’ profile, with more than a thousand tabs and various legacy extensions.

Summary results from test sessions

One point was most peculiar:

  • with a 1,044-tab session and all legacy extensions disabled, I discovered a 214-tab window where Firefox showed only two tabs.

From a twenty-three minute screen recording:

2017-10-16 03:47:41 frame
2017-10-16 03:47:41 frame.jpg1354×768 312 KB

I closed that bugged window, leaving an 830-tab environment for subsequent test sessions.

I began a session with all extensions disabled. After enabling the extension, Firefox was almost completely non-responsive for around twenty seconds. Two frames from a 150-second recording:

2017-10-16 04:34:14 frame
2017-10-16 04:34:14 frame.jpg1354×768 299 KB

2017-10-16 04:34:36 frame
2017-10-16 04:34:36 frame.jpg1354×768 227 KB

Twenty seconds …

… enabling a single extension, with Firefox 56.x and around 830 tabs. To put that in context:

Quantum Flow perspective

I’d like to enable Gecko Profiler and provide a profile –

Top Line Goal: Support Quantum Flow

– however I’m on a Tier-3 platform that can not use the extension:

#3

Here’s that short recording. Firefox unresponsive for around twenty seconds (04:34:14–04:34:36):

https://photos.app.goo.gl/IFEELwg8vSqekKag2

– playback is accelerated in places (see the clock, bottom left, speeding) but truly, the delay was around twenty seconds.

Following a brief discussion in IRC I planned to copy the root directory and cache directory of the affected Firefox profile to a Tier-1 platform – an old MacBook Pro where Gecko Profiler is installed, and appears to usable, with Firefox 56.0 (64-bit) on pre-release Mac OS X 10.13.1.

OT (thinking this through): some testing with that particular Mac, where USB is limited to 2.0, is hindered by my use of Apple File System for the startup volume on a hard disk drive. if you’re interested in performance issues with APFS, follow https://framasphere.org/tags/apfs – there’ll be more from me when things are less busy. Back on topic …

It’ll probably be easiest for me to test data from the affected Firefox profile with 56.x on 10.9.5 (Mavericks).

#4

Further investigation suggests that it was normal, not peculiar. From test results today I see:

  • with Firefox in safe mode, hidden tabs are not shown

– by design, I guess.

Does https://bugzilla.mozilla.org/show_bug.cgi?id=1362595#c3 support that guess?