[Defy Android Development] YetAnotherForumUser:
Did you get the 'ringtone' bug in Quarx 20130220? With kernel 2.6.32.9?

If your phone is starting to exhibit lag try to find out why that is happening. Run procrank and procmem on the highest ranking processes in procrank. Run top to find cpu hogs, look for runaway native processes. Check vmstat and /proc/meminfo for memory use. Check /proc/overclock/info to check whether your phone is running at the expected speed(s). Run logcat in a remote terminal, cat /proc/kmsg (needs root) in another and watch for anomalies (segfaults, forced restarts, runaway OOM killer, etc). Observe, record and publish your finds. Don't forget to include your phone model, distribution, kernel, modifications, configuration, whether you installed from a clean slate or on top of a creaky stock rom without wiping anything - or anything in between, etc...

---------- Post added at 01:30 AM ---------- Previous post was at 12:34 AM ----------

Tired of all the inconclusive reports of this or that kernel doing such and so on his or her phone I decided to misappropriate my wife's phone for some experimenting. That is not what I told her of course but anything I do to the poor thing will make it perform better than it did anyway so I feel no guilt.

On her phone I installed Quarx 20130220. On my phone I have 'my' latest build containing the JellyX kernel, as described and linked in a previous message. Both phones are model MB526, both run slimmed down gapps. Mine is a bit more slimmed down, especially where it concerns Google services which are disabled in normal use. My phone is set to 160 dpi (I like small print), hers to 240 dpi (she doesn't). I tend to use the 'smart' bits of the thing more than she does, she uses the 'phone' part a lot more than I do. I use it to read books but I never play games, she does the opposite. My phone sees about 1.5 to 2 hours of screen time per day, hers between 1 and 1.5 hours. At home we both connect to the local wifi network but away from home we're on different networks. In other words, these phones are technically identical but they see different usage patterns. Still I think there is some base for comparison, hence my experiment.

Both phones have been running for about 14 hours. In that time we have been on and around the farm here in the Swedish countryside so the network conditions to which the devices have been exposed are comparable. Here are some statistics:

Mine Hers

Battery

charge 87% 63%
Android System 40% Android OS 52%
(keep awake 2h 49m) (keep awake 8h 20m)

BetterBatteryStats wakelocks

kernel 28m deleted_wake_locks 9h 40m deleted_wake_locks

partial 1h 14m AlarmManager No significant partial wakelocks
1h 3m ConnectivitySrv

BBS other

deep
sleep 11h 18m 5h 10m

In other words, both phones exhibit excessive reported battery use by some piece of Android-related code. When I triumphantly declared to have found the cause of the excessive battery 'use' of Android System I may have been slightly premature (even though the patch I made is still valid and still corrects a logic bug in the code). When I touch the refresh icon on my phone I notice the words 'com.cyanogenmod.settings.device' quickly flash in the position of Android System. On her phone Android System only accounts for 5% of battery use, here the word 'Surfaceflinger' flashes on screen before being replaced by Android System. Android OS does not flash at all, but the 'keep awake' time which is attributed to Android OS more or less matches the 'No or Unknown Signal' category in BBS/Other. Her phone only slept for 5h 10m, which more or less matches the time BBS reported a good signal. Battery Statistics does not show anything resembling those hours and hours of 'no or unknown signal'.

So... there is still something strange going on on both phones, even though they run different kernels. This means the cause of the observed misbehaviour either lies outside of the kernel or it is present in both 2.6.32.9 as well as 2.6.32.60-JellyX. Battery consumption on 2.6.32.60-JellyX seems to be better than on 2.6.32.9 but this could be explained by the other observed differences. More study is needed to get to the bottom of this (said the scientist looking for more grant money) so I'll do some more experimenting, starting with my phone.