Animating Icon eats up CPU and slows dows unity-panel-service

[Owais Lone]

[Impact]
Users running a Qt application with a systemtray icon which updates its icon frequently to produce an animation will get unity-panel-service to use all CPU.
This is because sni-qt continuously generate new images for the icon which unity-panel-service has to decode.

Skype is an example of application which triggers this bug.

[Development Fix]
Bug has been fixed upstream in sni-qt 0.2.6 by computing md4sums of the icon pixels, making it possible to reuse existing images instead of always generating new ones.

[Stable Fix]
debdiff attached to this report backports revision 88.1.4 of upstream, implementing the md4sum.

[Test Case]
1) Open Skype
2) Disconnect from internet. Skype icon starts to animate
3) Notice Skype unity-panel-service starts eating up the CPU and often making indicator menus unresponsive or lag like Ubuntu is running on a 200mhz cpu

[Regression Potential]
No regression expected. The fix has been tested from a PPA for a while now.

[Aurélien Gâteau (agateau)]

Thanks for your report.

I have an idea to fix this bug but it is non-trivial so I am not going to rush it for the Oneiric release. We will fix it with a SRU. I am probably going to provide the fix in the sni-qt PPA before though.

[Owais Lone (loneowais)]

Great News.

Thanks for the awesome work

[Aurélien Gâteau (agateau)]

Can you try version 0.2.6~bzr89 from the sni-qt ppa? It should fix this problem.

[Owais Lone (loneowais)]

Perfect! Reduces unity-panel-service cpu usage from 80-95% down to 0-5%

Thanks!

[Aurélien Gâteau (agateau)]

Here is a debdiff backporting the fix.

[Launchpad Janitor (janitor)]

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

[Chris Halse Rogers (raof)]

Hello Owais, or anyone else affected,

Accepted sni-qt into oneiric-proposed, the package will build now and be available in a few hours. Please test and give feedback here. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you in advance!

[Owais Lone (loneowais)]

I purged the ppa and downgraded to 0.2.5-0ubuntu3 from oneiric proposed.

I can confirm that the fix is working.

[Troex Nevelin (troex)]

I can confirm my CPU usage went down from 100% to 5% when skype icon rotating

[TomaszChmielewski (mangoo-wpkg)]

And what CPU usage is it when it doesn't rotate? Using 5% CPU to to animate a 25x25 px area is still quite high.

[Launchpad Janitor (janitor)]

This bug was fixed in the package sni-qt - 0.2.5-0ubuntu3

---------------
sni-qt (0.2.5-0ubuntu3) oneiric-proposed; urgency=low

  * Backport r88.1.4 from upstream trunk: avoid causing unity-panel-service to
    eat all CPU when an application uses an animated icon (LP: #865601)
 -- AurAlien GAteau <email address hidden> Tue, 25 Oct 2011 15:52:35 -0400