Scrolling through song list in music scope is very laggy

[Michi Henning]

Untar the attached archive into the Music folder. Go to the music scope and navigate through the tracks tab. Scrolling up and down the song list is very slow and jerky, and thumbnails take a long time to appear even after the cache is warm.

[Michał Sawicz (saviq)]

Something somewhere is likely blocking the UI thread when loading the images.

[Michi Henning (michihenning)]

Hmmm... That would rule out the scope itself, wouldn't it? It doesn't ever get access to the UI thread.

[Albert Astals Cid (aacid)]

Not sure if it's something blocking the UI, the CPU usage of unity8-dash goes to 99.99% according to top so it may be we're doing to much stuff in the main thread?

[Albert Astals Cid (aacid)]

The code at https://code.launchpad.net/~aacid/unity8/moreAsyncAudioCard makes things a bit better by making image more async so that it doesn't happen in the main thread.

It's not perfect yet but that's what i could find in a quick look.

[Launchpad Janitor (janitor)]

This bug was fixed in the package unity8 - 8.11+16.04.20160310.4-0ubuntu1

---------------
unity8 (8.11+16.04.20160310.4-0ubuntu1) xenial; urgency=medium

  [ Albert Astals Cid ]
  * Add context for Re-dock as asked by translators (LP: #1534608)
  * Add emblem to the preview header widget (LP: #1424720)
  * Add haptics to ScopesListCategoryItem buttons
  * Audio Cards: Make some of the image loading async (LP: #1533432)
  * Do not create fallback code for the card tool fake card (LP:
    #1545865)
  * Fix resizing the dash bringing temp scopes size out of sync (LP:
    #1543130)
  * Minor fixes for unity-scope-tool
  * Resolve title alignment on card creator time instead of on runtime
  * Use fixedHeaderHeight only in the non cardtool cards
  * Use the new undeprecated connectivityqt::Connectivity
  * asynchronous is only false on the fake card in cardtool
  * clazy fixes

  [ Albert Astals Cid, CI Train Bot ]
  * click scope: Add the else branch so we reset the card size in all
    situations

  [ Andrea Cimitan ]
  * PreviewSharing widget now accepts both string and array of
    widgetData["share-data"]["uri"] (LP: #1549056)
  * Update AP tests for new single preview
  * Use Text.Wrap for body notification text (LP: #1544909)

  [ Andrea Cimitan, Lukáš Tinkl, Michael Zanetti, Nick Dedekind ]
  * some fixes for the new palette (LP: #1554616)

  [ CI Train Bot ]
  * Resync trunk.
  * Update translation template

  [ CI Train Bot, Daniel d'Andrada ]
  * Ensure the QML engine doesn't delete our mock MirSurfaces on its
    own.

  [ Daniel d'Andrada ]
  * tst_Shell: Remove unused qml items

  [ Josh Arenson ]
  * Allow the shell to blacklist input devices and force the OSK shown.
    (LP: #1542224)

  [ Lukáš Tinkl ]
  * Disallow resizing windows up, past the Panel (LP: #1544766)
  * Elide the window title not to let it overflow into the indicators
    area (LP: #1535767)
  * Enable the PIN lockscreen to be used with a HW keyboard (LP:
    #1550359)
  * Fix tiny windows when switching stages
  * Provide a range of ports to QML JS Debugger
  * Watch for launcher item icon changes (LP: #1543290)

  [ Michael Terry ]
  * Proxy more mouse and touchpad properties to USC (LP: #1540398) (LP:
    #1543344, #1540398)
  * Refactor the AccountsService plugin and make it slightly faster.
  * To let the user log in if a mouse is connected, hide the greeter
    cover page on a mouse click (but NOT a touch click). (LP: #1540497)
  * Watch AccountsService for changes to the user's real name. This was
    preventing us from noticing when the user set their name in the
    welcome wizard.

  [ Michael Zanetti ]
  * Allow alt+tabbing in staged mode too (LP: #1540502)
  * Allow invoking the staged mode spreads by mouse right edge pushes
    too (LP: #1540392)
  * Allow loading the device configuration from an external file
  * Implement Launcher's keyboard navigation and updated pip design
  * Make launcher scalable, allow it locking (LP: #1511015)
  * Properly parent launcher items in all cases (LP: #1495732)
  * Read inputMethod surface from the new property int QtMir (LP:
    #1545286)
  * Some visual updates and rotation lock for the virtual touchpad (LP:
    ...