bug or feature? XO hogs CPU trying to find Mesh while already connected to Access Point
|Reported by:||thomaswamm||Owned by:||marco|
|Component:||sugar||Version:||Development build as of this date|
|Keywords:||relnote blocks-:8.2.0 cjbfor9.1.0||Cc:||mstone, marco, mtd, gregorio, dsd|
|Blocked By:||#4074, #6944||Blocking:|
|Deployments affected:||Action Needed:||diagnose|
Testing beta build 8.2-760. Found a situation that hogs CPU time. There seem to be multiple variations, but I will try to simplify:
When I resume from suspend (using power button), my XO tries first to find a mesh. I am impatient to get back online, so in Neighborhood view I click on my WiFi Access Point, which then connects within a few seconds. The frame then shows both the AP icon (connected) and the Mesh icon (still searching for a connection, and pulsating for hours). Is this a bug, or a feature?
This situation correlates with increased & prolonged CPU usage by sugar-shell, shown by 'top' in Terminal. Even more, multiple repetitions of (disconnect AP, then connect AP) will increase CPU usage by sugar-shell even more, up to around 50%, which makes the XO more sluggish.
I also got into a situation (maybe by double-clicking my Access Point icon) where both AP icon and Mesh icon were both pulsating grey and trying to connect. It sat like that for 2 hours (no change), and 'top' showed 75% CPU usage by sugar-shell. Then with some trial & error clicking it went almost back to normal (only 10% CPU) and AP connected normally.
Logs and screenshots coming. This ticket might help explain #8098.
By the way, normal behaviour for my XO is to be only connected to my AP (and not trying to also connect to Mesh). And sugar-shell normally only uses a few % of CPU. 'Normal' logs also coming.
Now that I understand the behaviour, I can avoid this bug (or feature?). I don't know if it will be a nuisance for other users (G1G1 or schools). It can waste CPU cycles.
Sugar might be wasting CPU cycles while misrepresenting what Network Manager is doing (but I am usually wrong).
Change History (33)
comment:1 Changed 7 years ago by cjb
- Cc mstone marco added
- Component changed from performance to sugar
- Owner changed from cjb to marco
comment:5 Changed 7 years ago by marco
- Action Needed changed from reproduce to diagnose
- Milestone changed from Not Triaged to 8.2.1
Changed 7 years ago by mtd
comment:21 Changed 6 years ago by mstone-xmlrpc
- Keywords cjbfor9.1.0 added
- Milestone changed from 8.2.1 to 9.1.0