unity8+Mir draws more current and wakes up 100 times more often than unity8 with surfaceflinger
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
Mir |
Expired
|
High
|
Unassigned | ||
The Ubuntu Power Consumption Project |
Expired
|
Undecided
|
Unassigned | ||
unity-mir |
Incomplete
|
Medium
|
Unassigned | ||
unity8 (Ubuntu) |
Expired
|
Medium
|
Unassigned |
Bug Description
I've looked at the CPU, wakeup event and current drawn on a LG Nexus 4 comparing the Mir enabled and non-Mir versions of Unity8 with today's image + updates (at 18:00 UTC, 7th Oct 2013).
I ran a 5 minute idle soak test with the screen set to be un-blanked at full brightness and measured the current drawn at 0.5 second intervals. The Mir enabled version of Unity is drawing on average ~143.7mA where as the non-Mir version is drawing 138.7mA, or around 5mA less current (~3.6% difference)
Measuring CPU load (just Mir)
Mir:
0.70% user, 0.63% system, 1.33% total CPU usage
Non-Mir:
0.17% user, 0.07% system, 0.23% total CPU usage
Context Switches:
Mir:
219.24 context switches/sec
Non-Mir:
22.32 context switches/sec
poll/epoll/
Mir:
4.9664/sec
Non-Mir:
3.1333/sec
Total CPU of system:
Mir:
0.87%
Non-Mir:
0.70%
So it seems that the Mir variant of Unity8 is busier and consumes more power than the non-Mir variety when idle.
affects: | ubuntu → unity8 (Ubuntu) |
no longer affects: | unity8 |
Changed in ubuntu-power-consumption: | |
status: | New → Incomplete |
You'd need to take surfaceflinger into account when comparing those, as there's no separate display server process now.