[BetterBatteryStats] hnn:
A sleepless night with Suspend Backoff

Hi,

I had a strange experience last night. After having played around a lot recently with Tasker, and doing a lot of other things since I last rebooted my unrooted Galaxy S4, I thought I should take a look at the battery stats, just to see if there was anything new draining the battery. So I used Android Tuner's Kill Apps (which does nothing hurtful to my apps), unplugged the phone before going to sleep, and waited eagerly for the morning.

This is what I found, after also using the phone for an hour before realizing I should make a dump to show you: (edited to limit screen space for you):

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Statistic Type: Unplugged to Current

Since 8 h 31 m 12 s

Rooted: false

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Battery Info

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Level lost [%]: Bat.: -68% (100% to 32%) [8,0%/h]

Voltage lost [mV]: (4331-3703) [73,7%/h]

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Other Usage

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Deep Sleep (): 15 m 37 s (937 s) Ratio: 3,1%

Awake (): 8 h 15 m 35 s (29735 s) Ratio: 96,9%

Screen On (): 1 h 9 m 45 s (4185 s) Ratio: 13,6%

Wifi On (): 8 h 31 m 12 s (30672 s) Ratio: 100,0%

Wifi Running (): 8 h 31 m 12 s (30672 s) Ratio: 100,0%

No Data Connection (): 8 h 31 m 8 s (30668 s) Ratio: 100,0%

No or Unknown Signal (): 8 h 31 m 8 s (30668 s) Ratio: 100,0%

Screen dark (): 7 s (7 s) Ratio: 0,0%

Screen dimmed (): 1 h 1 m 59 s (3719 s) Ratio: 12,1%

Screen medium (): 1 s (1 s) Ratio: 0,0%

Screen light (): 39 s (39 s) Ratio: 0,1%

Screen bright (): 6 m 58 s (418 s) Ratio: 0,8%

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Wakelocks

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NetworkLocationLocator (Google-tj��nster): 1 h 37 m 40 s (5860 s) Count:1289 19,1%

AlarmManager (de.android.telnet2.Network Signal Info Pro): 2 m 45 s (165 s) Count:9068 0,5%

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Kernel Wakelocks

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"suspend_backoff" (): 4 h 28 m 31 s (16111 s) Cnt:(c/wc/ec)1613/0/1613 52,5%

"wlan_ctrl_wake" (): 1 h 34 m 15 s (5655 s) Cnt:(c/wc/ec)630/0/630 18,4%

"PowerManagerService" (): 1 h 32 m 10 s (5530 s) Cnt:(c/wc/ec)7768/0/0 18,0%

"wlan_wd_wake" (): 23 m 3 s (1383 s) Cnt:(c/wc/ec)24889/0/0 4,5%

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The interesting thing is that during the night, it lost 6% battery per hour, where I usually only loose 1-2%, even when GPS, Wifi and Data is on, but to reach that, I need to have a nicely clean and rebooted phone.

The phone was only in Deep Sleep for 15 min, the rest of the night it was wide awake! But the only big thing showing up in Wakelocks is Network Location Locator, but only for 1h37m. However, in Kernel wakelocks, I have suspend_backoff for 4h 28 minutes! I have now seen in other threads that this is due to OS activity, possibly related to Wifi activity, and nothing from user applications. I have never seen somthing like this before.

Another indication that something was wrong was that the Samsung widget Application Monior (also reached by Home Button/Long press/Circle) showed two SYSTEM programs as active: Google Framework Services and Google Play Services. Usually,only user programs are shown here. So for some reason, these two system services seemed to have taken hold of the phone. Could they have been the culprits for "suspend_backoff"?

I terminated the two "Active Programs" using the Samsung application, and now the phone is back to 1-2% per hour. Before going to sleep myself last night, I had used Android Tuner to Kill All processes (except system processes which of course can not be killed on a standard phone), but in some way Samsung's application could kill them.

Lesson learned: Check Active Programs regularly, possibly reboot the phone daily. Because I still like to have Wifi, GPS and data enabled during the day, without loosing another 4% of battery per hour.

Comments are welcome to my story!