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Root Battery Usage in Jiilik's rom v008?

Discussion in 'Android Devices' started by jiilik, Dec 12, 2011.

  1. jiilik

    jiilik Well-Known Member
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    Hi guys - not sure if it's just my imagination, but since I've upgraded to v008 of my rom, I've noticed a substantial increase in the phone's battery life. I don't have anything quantitative to back this up. Anecdotally, however, I've found that I can go four days or more without having to charge, even with mobile network turned on. Previously I had to plus in the phone nearly every night or it'd be dead in the morning.

    Does anyone have any corroborating evidence, or am I imagining this? Also, if I wanted to quantify this, does anyone know of any good tools?

    Cheers
     

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  2. karendar

    karendar Android Enthusiast
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    It does drain alot less quickly, I do agree. My girlfriend can go 2 days without charging her phone easily! Before, she needed it charged every night.
     
  3. BabblingCamel

    BabblingCamel Newbie
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    The battery seems to last quite a bit longer with me as well.
    What seems quite odd to me is that even though I have the CPU overclocked to 806 Mhz ondemand, it still lasts longer without overclocking. (The fact that I have the minimum frequency set to 122 Mhz may also be a contributing factor)

    Either way, it does indeed seem your rom offers better power management :D
     
  4. jiilik

    jiilik Well-Known Member
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    Yeah, I've been running 806 max, 245 min with ondemand governor and I'm three days in now... I haven't plugged it in except briefly to my laptop now and again to run adb after flashing failed attempts at building cyanogenmod. :D Probably hasn't been charging for more than an hour in the last three days.

    I have two hypotheses about what causes this: theory 1) Adaptive Voltage Scaling (AVS) which I turned on in v008, but am not really sure what this does.

    theory 2) Overclocking may actually be good for battery life; consider that the phone has to spend perhaps 30% less time in high powered states - less if you consider that the memory is running like 100% faster. This allows the phone to spend more time in lower power states. Since most of the embedded features of the chip all run at the same speed, this means that averaged over time, the phone uses less power.?

    Anyway, I'll see if I can find out more. Maybe there's additional improvements I can make.
     
  5. karendar

    karendar Android Enthusiast
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    There is an article saying that CPU time doesn't really affect battery life all that much, neither does voltage. What does affect it is more intensive components like GPU, radio and display. They're the real battery hogs in a system. Actual power consumption of a CPU like ours is very minimal and it actually produces very little heat for the type of system we have. Android isn't a demanding software in itself, the apps that use all the random components are though. Keep this in mind: When you play an online game, what's solicited? In order: Touchscreen, GPU, Wifi/3G, CPU because most of the work is done on the display part.

    When you run the web, what's solicited? Touchscreen, Wifi/3G, CPU (Which is very minimal, because rendering isn't ressource intensive, so CPU doesn't work as much).

    As for overclocking, all it'll do is produce more heat when CPU is stressed and require a bit more voltage in some instances. What Adaptive Voltage Scaling does is adjust voltage according to demand. If your CPU is clocked at 800 mhz and your voltage is stock, considering the CPU isn't considered stable at this speed, AVS will bump the voltage automatically to compensate for the demand to the CPU if it's insufficient. This is why Angry Birds seems to have stabilized after enabling this feature. On the other hand, if CPU is idle, voltage will drop. This is true for both the GPU and the CPU, considering they're actually shared according to docs I've read.

    Also, if you set to ondemand governor, most of the time the CPU will be clocked down and only bump up for bigger requests. It's also one of the most universal governors out there and most loved for battery life. Alot of immitations started popping up left and right, but I always go back to ondemand.
     
  6. chimpanzee

    chimpanzee Lurker
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    Intel's study suggested that fast CPU actually may end up better for battery life, so long the OS is written properly so that most of the time it is in 'sleep' or minimium speed mode(and wake up then do its task ASAP due to fast CPU). If the OS(and the apps) are poorly written so there is some background program running(with the screen already off) constantly, the battery would be drained at no time, even with a slower CPU.

    The same thing applies to phone too.
     
  7. jiilik

    jiilik Well-Known Member
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    On my laptop, I have an old intel tool called powertop which monitors which apps are waking up from idle preventing the cpu from sleeping. It looks like a version is available for arm as well, and should run fine from an adb shell or similar. Would actually be an interesting diagnostic tool during sleep. I wonder if we could leave it running over an adb shell while the phone goes into one of its screen locking fits....

    May investigate more later.
     

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