UCUnits::resolveResource takes up to 23% of unity8-dash's CPU time when scrolling a long scope

I have no magic fix for this though, suggestions include:
 * Remove this fuzzy matching of filenames
 * Somehow give the hability of opting out of this fuzzy filename matching
 * Caching the last X dirs, so at least repeat queries (like going up/down the same scope) are a bit faster.

This might be a direct duplicate of bug 1494795.

Because that was about 100% CPU on arale, which might be the same as only 23% CPU on a desktop or whatever you're using.

No, it's not a direct duplicate.

Status changed to 'Confirmed' because the bug affects multiple users.

Can we verify the following assertion? if you specify "foo.png" and rely on scaling, on disk it will have to be "foo@18.png" (replace 18 with any number(s)) and NEVER "foo.png". So why doesn't the lookup skip all the suffix search if the file "foo.png" exists verbatim?

This bug was fixed in the package ubuntu-ui-toolkit - 1.3.2060+16.10.20160814

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ubuntu-ui-toolkit (1.3.2060+16.10.20160814) yakkety; urgency=medium

  [ Zoltan Balogh ]
  * Fix OptionSelectorTestCase tests.
  * Fix more OptionSelector autopilot tests

  [ Timo Jyrinki ]
  * Disable documentation building for GLES builds. Fixes LP: #1606222.
  * Replace abs with qFabs due to GCC6 breakage. Fixes LP: #1610943.
  * Limit s390x dependencies more due to upstart/s390x problems and removed
    packages in archives. Fixes LP: #1610951

  [ Andrea Bernabei ]
  * ListItemLayout doc: add elide mode change example and add section about
    labels default properties values. Fixes LP: #1603450.
  * ListItemLayout doc: add explicit note about the need to bind ListItem's
    height to layout's height.
  * More Scrollbar optimizations: 20% faster creation time. Fixes LP: #1606451
  * Scrollbar: fix wrong thumb color on tap/mouse release and increase coverage
    of hover states unit tests. Fixes LP: #1608897

  [ Zsombor Egri ]
  * Fix null pointer property initializer used with 1.3 PageWrapper.
    Fixes LP: #1604780.
  * Fix BottomEdge content URL preloading. Fixes LP: #1604509.

  [Albert Astals Cid ]
  * UCUnits::resolveResource: Prefer image path if it exists. This saves
    searching the disk for @gu images, which is a big speedup. According to
    callgrind loading 100 images from a folder that contains 380 images goes
    from around 3 million instructions per UCUnits::resolveResource call down
    to around 10 thousand. This optimization is ok since it is not correct to
    ship both image.png and image@20.png. You either have to ship gu-enabled
    files or not, but mixing them is not allowed. Searched for cases in which
    that may be happening in my phone and found none. Fixes LP: #1604029.

  [ Tim Peeters ]
  * Configure colors of the buttons in the ActionBar and PageHeader through
    their Styles. Fixes LP: #1597774.
  * Fix assigning of constant values to a grouped property in StyleHints.
    Fixes LP: #1602836.
  * Fix list view keyboard navigation for RightToLeft and BottomToTop
    directions. Fixes LP: #1605634
  * Use external QML files instead of embedded QML strings for autopilot tests.
    Fixes LP: #1578319
  * Fix failing autopilot header tests.
  * Fix ActionSelectionPopover Autopilot CPO tests.

  [Christian Dywan ]
  * Include indexes in "offline" docs and filter out link errors.
    Fixes LP: #1603937.
  * Increase focus ring thickness from 1dp to 2dp. Fixes LP: #1602690.
  * Add a snippet about tests to the toplevel README
  * Enter/Return to trigger, Space to expand ComboButton. Fixes LP: #1523817.
  * Initialize engine variable before using it in the _engine case.
  * Use Qt.rgba instead of #0000 checking ListItem default color.
    Fixes LP: #1560004
  * Don't use a different .desktop file in the gallery tests.
    Fixes LP: #1578319
  * Update scaling docs, set QT_SCALE_FACTOR and unset GRID_UNIT_PX.
    Fixes LP: #1610208

  [ Florian Boucault ]
  * Sections: load Icons asynchronously.

 -- Zoltán Balogh <email address hidden> Sun, 14 Aug 2016 09:06:46 +0000