772763 - Opening plugins stream blocks the browser for 70ms per stream (2 seconds with multiple videos)

Status: RESOLVED INCOMPLETE

(Core Graveyard :: Plug-ins, defect)

Description

[timbugzilla]

Browser responsiveness (with moz-central nightly builds) when opening pages with several flash video embeds seemed to become quite a lot worse a few weeks before flash 11.3 (stable builds) were released. The following pages (found on google by searching for 'youtube videos thread') reproduce those issues reliably, especially with less powerful hardware.

http://www.firefallthegame.com/community/threads/the-unofficial-official-thread-of-funny-youtube-videos.32427/

http://www.firefallthegame.com/community/threads/the-unofficial-official-thread-of-funny-youtube-videos.32427/page-2

The nightly profiler was used to examine opening the 1st URL. The full profile is here:

http://people.mozilla.com/~bgirard/cleopatra/?report=AMIfv95Cje7fa5piWaV-oNKE9IEVKnkgK40itgsHFKT0wX1D64PttdNMglwM6WCG1Nf-MGlWrfwWD5Tf0Vw-d1hrq3MEN6VUQraLtDff7INJNhNmEnvukex4XdALBMFcnKrDVufNS7pgVhLmwrZYsJI-APHa-v939g

A "view" of the jank (red) period is here:

 http://people.mozilla.com/~bgirard/cleopatra/?report=AMIfv97s3uecrnDSfG8OLoMPLFOO1ctGk4haS9Wi8Mq1VUCrzhblCeGsv6A-ucDjtYFIqlnbvLIHMofiGk2JZ7kgaI7kvnwLtCBCsCyBGEFWGEq-M_vwFFBLrwO9F6u2FViSfVAUbA-LOKFWzcbD5__nwfW_Lp_YBw

For this view > 85% of the time was spent in KiFastSystemCallRet from ntdll.dll.

Jank stats:

    Avg. Responsiveness:
    490.99ms
    Max Responsiveness:
    1886.75ms
    Real Interval: 10.13 ms +-30.11

A "Sync plugin constructor" icon was shown in this profile.

The profiling was done with a fresh default profile on the win32 2012-07-10 moz-central nightly build. System was 32bit Win7 on an AMD E-350 based with D3D9 compositing for layers forced in nightly. About:support is attached.

Hangs/jank were also seen (to a lesser degree) on an Intel E-8500/ATI HD4650 based system running win7 64bit, with D2D/D3D10 GPU acceleration. (Most time was spent in NtWaitForMultipleObjects and NtUserWaitMessage on this system.)

Comment 1

[timbugzilla]

Attachment: about:support for nightly on AMD E-350 based laptop

Comment 2

[Benoit Girard (:BenWa)]

The profiles shows that streams takes 70ms to open each and you're opening many streams so it quickly adds up to block the browser for over 1.8 seconds continuously, several seconds total.

Comment 3

[timbugzilla]

Thanks for the analysis! If I can help with any further profiling then please let me know.

Cheers,

Tim.

ps. Click-to-play is a nice work around.

Comment 4

[Benjamin Smedberg]

Resolving old bugs which are likely not relevant any more, since NPAPI plugins are deprecated.