Canonical System Image

When an application is suspended or closed it causes a large UI stutter

Bug #1518935 reported by Andrew Hayzen
76
This bug affects 17 people
Affects Status Importance Assigned to Milestone
Canonical System Image
Fix Released
High
Michał Sawicz
Canonical System Image 14 "OTA14"
qtmir (Ubuntu)
Invalid
High
Unassigned
ubuntu-app-launch (Ubuntu)
Fix Released
High
Ted Gould

Bug Description

When an application is suspended or closed it causes a large UI stutter.

What happened:
1) Open multiple applications (eg Browser and Music)
2) Switch from Browser to Music
3) Scroll up/down a listview
4) Around 2 seconds after switching from Browser to Music the process is suspended and it can be observed that a UI stutter occurs

What I expected to happen:
At step 4) for there to be no stutter in the UI

Note that this also occurs if you close an application, and happens when switching from an application to the scopes.

$ system-image-cli -i
current build number: 169
device name: mako
channel: ubuntu-touch/rc-proposed/bq-aquaris.en
last update: 2015-11-23 01:08:21
version version: 169
version ubuntu: 20151120.1
version device: 20150911
version custom: mako-1.1

Tags: performance

Related branches

lp://staging/~ted/ubuntu-app-launch/non-blocking-resume
Charles Kerr (community): Approve
unity-api-1-bot: Approve (continuous-integration)
Michał Sawicz: Needs Fixing
Diff: 470 lines (+158/-126)
6 files modified
libubuntu-app-launch/application-impl-base.cpp (+97/-75)
libubuntu-app-launch/application-impl-base.h (+15/-6)
libubuntu-app-launch/application-impl-libertine.cpp (+1/-2)
libubuntu-app-launch/registry-impl.cpp (+19/-26)
libubuntu-app-launch/snapd-info.cpp (+1/-1)
tests/libual-cpp-test.cc (+25/-16)
Michał Sawicz: Approve
Diff: 470 lines (+158/-126)
6 files modified
libubuntu-app-launch/application-impl-base.cpp (+97/-75)
libubuntu-app-launch/application-impl-base.h (+15/-6)
libubuntu-app-launch/application-impl-libertine.cpp (+1/-2)
libubuntu-app-launch/registry-impl.cpp (+19/-26)
libubuntu-app-launch/snapd-info.cpp (+1/-1)
tests/libual-cpp-test.cc (+25/-16)
Revision history for this message
Launchpad Janitor (janitor) wrote :

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

Changed in unity8 (Ubuntu):
status: New → Confirmed
Revision history for this message
Michael Zanetti (mzanetti) wrote :

This is the relevant debug output while the stuttering occurs.

qtmir.surfaces: MirSurface["webbrowser-app"]::stopFrameDropper()
qtmir.applications: Application::setInternalState - appId= "webbrowser-app" state= SuspendingWaitProcess
qtmir.applications: TaskController::suspend - appId= "webbrowser-app"
qtmir.applications: Application::setInternalState - appId= "webbrowser-app" state= Suspended
qtmir.applications: ApplicationManager::onAppDataChanged: Received "state" update "webbrowser-app"

affects: unity8 (Ubuntu) → qtmir (Ubuntu)
Michał Sawicz (saviq)
Changed in qtmir (Ubuntu):
status: Confirmed → Triaged
importance: Undecided → High
Pat McGowan (pat-mcgowan)
Changed in canonical-devices-system-image:
assignee: nobody → Michał Sawicz (saviq)
importance: Undecided → High
status: New → Confirmed
milestone: none → backlog
Revision history for this message
Andrea Bernabei (faenil) wrote :

I'm currently seeing many-seconds delay on rc-proposed r308 on Krillin...

Not sure how I got there (yet) but when I switched from one app to others, it was freezing for a few seconds every time...pretty annoying :)

Revision history for this message
Andrea Bernabei (faenil) wrote :

In my case, I was continuously switching between Telegram and Twitter apps (post a tweet, then switch, chat a bit, then switch, etc)...could it have something to do with the browser? (since it's also part of the usecase presented by the bug author)

Revision history for this message
Andrew Hayzen (ahayzen) wrote :

Agreed, from playing about with this for a while now, anything that is using oxide (webbrowser or webapp) seems to cause a very large and noticeable delay. Although it should be confirmed that other apps are not susceptible to this.

Revision history for this message
Albert Astals Cid (aacid) wrote :

Cut the rope (which is also oxied based) is also a big reproducer of this bug when switching from it to somewhere else (in case you need help with reproducing)

Revision history for this message
Michał Sawicz (saviq) wrote :

<ted> So I think that the answer is, yeah, we do that syncronously.
 We do a dbus call to cgmanager to get the list of pids and try to write their proc value.
 If we fail, then we need a setuid helper for things like oxide.
 So it could be that spawning that helper is part of what is causing a delay
 I'm not sure how to do it another way though.
 We're not blocking on it running, the overhead is just starting it.

Changed in qtmir (Ubuntu):
status: Triaged → Opinion
Daniel van Vugt (vanvugt)
tags: added: performance
Revision history for this message
Launchpad Janitor (janitor) wrote :

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

Changed in ubuntu-app-launch (Ubuntu):
status: New → Confirmed
Michał Sawicz (saviq)
Changed in ubuntu-app-launch (Ubuntu):
status: Confirmed → In Progress
Changed in qtmir (Ubuntu):
status: Opinion → Invalid
Changed in canonical-devices-system-image:
milestone: backlog → 14
status: Confirmed → In Progress
Changed in ubuntu-app-launch (Ubuntu):
assignee: nobody → Ted Gould (ted)
importance: Undecided → High
Revision history for this message
Daniel van Vugt (vanvugt) wrote :

Sounds like bug 1640443?

Revision history for this message
Pat McGowan (pat-mcgowan) wrote :

The silo works for me mx4 on proposed

Pat McGowan (pat-mcgowan)
Changed in canonical-devices-system-image:
status: In Progress → Fix Committed
Pat McGowan (pat-mcgowan)
Changed in canonical-devices-system-image:
status: Fix Committed → Fix Released
Ted Gould (ted)
Changed in ubuntu-app-launch (Ubuntu):
status: In Progress → Fix Released
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