High CPU usage (~10%) on Pro 5 when idle (with screen on)

[Michał Sawicz]

It was reported that the Pro 5 is draining battery and I can confirm we're seeing unusually high CPU usage when the device is idle (with screen on).

Steps:
* turn the screen on
* monitor top output

Expected:
* unity8 under/around 1% CPU usage

Current:
* unity8 around 10% CPU usage

I've confirmed it's not rendering, will be looking at a perf report when I get it.

ProblemType: Bug
DistroRelease: Ubuntu 15.04
Package: unity8 8.12+15.04.20160504.2-0ubuntu1 [origin: LP-PPA-ci-train-ppa-service-stable-phone-overlay]
Uname: Linux 3.10.100-user-01767-gf5aa556 aarch64
ApportVersion: 2.17.2-0ubuntu1.3touch1
Architecture: armhf
Date: Fri May 6 13:46:56 2016
InstallationDate: Installed on 2016-05-05 (1 days ago)
InstallationMedia: Ubuntu 15.04 - armhf (20160505-020304)
SourcePackage: unity8
UpgradeStatus: No upgrade log present (probably fresh install)

[Albert Astals Cid (aacid)]

I know you say it is not rendering, but just in case this happens in previews can you try if https://code.launchpad.net/~aacid/unity8/fasterMovingFakeHighlight/+merge/295071 fixes it?

[Michał Sawicz (saviq)]

So no, the above landed and the CPU still is at at least 3.4% CPU when idling on the greeter screen.

[Albert Astals Cid (aacid)]

I think the other bug you're seeing now is https://bugs.launchpad.net/ubuntu/+source/unity8/+bug/1588873

[Michał Sawicz (saviq)]

Nope, what I'm seeing is screen *on* and also I have silo 36 installed that has a fix for the above.