Bugzilla – Bug 11838
Idle drawing/ idle sleep uses a lot of CPU - could be a sucker of battery life
Last modified: 2009-04-27 10:02:24 UTC
Tested with 7.3 r3993 and 7.4r5226 , might be better to test with a newer 7.3. r3993 - A single line of scrolling text on the controller jumps /usr/bin/jive CPU usage (measured with top) from 6% to 26%. A NP screen with text that scroll takes about 36% cpu. Without scroll it uses about 10% Oddly, when the controller sleeps, the CPU usage goes UP to 26% while it is asleep. On 7.4 r5226, Idle NP (no scroll): 12% During sleep (from the NP screen): 26% I would think greater CPU% would use up more battery life, but I have no idea by how much.
Tom: is the Jive on battery or AC when you see this behavior? Richard: Your thoughts on this?
I'm fairly sure I tested on battery... I don't even think it goes into sleep on AC. I did a quick check with 7.4 on battery, and the results were the same as before. I don't see an easy way to determine whether this has battery life impact other than fixing the issue (removing the source of CPU during sleep) and comparing battery usage before and after.
Could this be related to the Controller battery bug 11619 ? or is this a different issue.
I don't think this is valid. When the entering sleep mode (normally after 1 minute) then the screen updates are turned off in SqueezeboxJiveApplet:_brightness() using: Framework:setUpdateScreen(lcdLevel ~= 0) Turning off screen updates prevents any rendering functions from working. The increase in CPU usage in sleep mode is due to the CPU being put in low power mode, running at 50MHz instead of 200MHz. I am concerned that the cpu usage generally seems higher than I remember it was, but that's a different bug.