Battery Life - Dalvik vs Optimized Dalvik vs ART

[p3ntyne]

Hi everyone,

I was just wondering how you felt about battery life with different runtimes - I use the optimized dalvik and for me, it has improved my battery life a little more than the others.

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[dancing-bass]

FWIW, I'm running CM11 (4.4 KitKat) on my Galaxy Nexus, on the latest nightly build. I have found that ART gives me better overall battery life when compared to Dalvik.

I am constantly amused by the fact that by running
1) a NIGHTLY rom (not listed as stable, or milestone... only nightlies so far!)
2) running ART (which CM states as officially unsupported)
3) on an older (and no longer supported) device

I'm able to get better performance (far less problems with lag, freeze-ups or shutdowns) AND better battery life then I could ever manage with the factory stock image (4.3 JB).

And yes I know it's not a N5 running a factory image of KK, but I figured I'd throw my 2 cents in. (By the way, what is Optimized Dalvik? this is the first I've heard of it!)

 

[mrsmumbles]

I'm also interested to know about optimized dalvik. I'm on stock unrooted and I switched to ART last night. No improvement in battery that I've noticed so far. My battery has been fine though, just not as good since I filled up most of the phone's internal storage (temporarily).

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[patruns]

In theory ART is faster and extends battery life because the apps are pre-compiled. With Davlik apps are compiled on the fly when you launch them. This increases speed when opening and also cuts down on processor load which should increase battery life. How much depends on the app involved, but I have noticed a slight increase in battery life as well as app start up. The downside is pre-compiling the apps take a little bit more drive space, though not much more.

 

[mrsmumbles]

In theory ART is faster and extends battery life because the apps are pre-compiled. With Davlik apps are compiled on the fly when you launch them. This increases speed when opening and also cuts down on processor load which should increase battery life. How much depends on the app involved, but I have noticed a slight increase in battery life as well as app start up. The downside is pre-compiling the apps take a little bit more drive space, though not much more.

Is this still true if I'm unrooted? Maybe I won't switch back then... Thank you for the info.

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[patruns]

Yes, rooting has nothing to do with it.

 

[mrsmumbles]

Yes, rooting has nothing to do with it.

Many thanks.

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[Shilohcane]

ART uses the cpu far less than dalvik in everyday use that extends the battery. Dalvik has to covert portable bytecode into executable code for the specific CPU in your phone every time you start up an App. ART converts all the Apps bytecode into executable code for the specific CPU in your phone just one time and stored it that way as a App ready to run in the CPU. So your App will never have to ever take that extra CPU step ever again under ART.

 

[mrsmumbles]

ART uses the cpu far less than dalvik in everyday use that extends the battery. Dalvik has to covert portable bytecode into executable code for the specific CPU in your phone every time you start up an App. ART converts all the Apps bytecode into executable code for the specific CPU in your phone just one time and stored it that way as a App ready to run in the CPU. So your App will never have to ever take that extra CPU step ever again under ART.

That sounds really good.

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[Shawn Magm]

Just converted. I'm interested in seeing any difference. I did 2 hard resets recently because I'm not sure if an app broke my wifi's ability to hold onto my home router. It's been fine since the hard reset. I've also cut down on the number of app installed (no facebook, twitter, instagram, and a bunch of other apps, I use the mobile site instead), and standby time has been stellar. Maybe 0.5%-1% drainage per hour. I see if ART improves upon this.

 

[p3ntyne]

Optimized dalvik is the bionic and dalvik libraries from the moto x, they are supposed to increase performance and battery life.

So does anyone else have experience with those two? I would really like to know.

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[undulose]

I have just switched to ART. I'm gonna observe for a few weeks and see if there's a drastic change in battery life and performance. The things I've noticed, though, are less RAM and 0.6 GB added to my storage.


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[p3ntyne]

I have just switched to ART. I'm gonna observe for a few weeks and see if there's a drastic change in battery life and performance. The things I've noticed, though, are less RAM and 0.6 GB added to my storage.


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Yeah, I guess that's the downside...

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[yfan]

ART does take a bit more storage, but I'm happy to spare the room on my 32 GB N5 for the performance and battery life improvement it delivers.

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[undulose]

ART does take a bit more storage, but I'm happy to spare the room on my 32 GB N5 for the performance and battery life improvement it delivers.

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Same here man. I don't feel compromised having less storage since I'm not a storage junkie like others. I still have 10.3 GB free. ^_^

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[p3ntyne]

Same here man. I don't feel compromised having less storage since I'm not a storage junkie like others. I still have 10.3 GB free. ^_^

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Is that all, I have 24Gb free and nothing to fill it with...

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[undulose]

Is that all, I have 24Gb free and nothing to fill it with...

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Can't beat that man!

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[Shawn Magm]

So far, so good. Idle time has been markedly improved. I'm going on 12 hours from my last charge, and my N5 has only dropped 3% from 100 to 97%. Under Dalvik, I'd be anywhere from 87% to 94%.

 

[KC1988]

Two weeks ago, I changed to ART. I reverted back to Dalvik. I saw perhaps very minor speed improvements in app usage. The downside was the overnight standby battery. On Dalvik, phone loses 5% or less with phone on (wifi on, cell on, no background apps). On ART, the phone lost 20-25% overnight. This was over 3 night period, so I switched back to Dalvik. During the day, didn't see any battery improvement.

 

[dancing-bass]

I'm also interested to know about optimized dalvik. I'm on stock unrooted and I switched to ART last night. No improvement in battery that I've noticed so far. My battery has been fine though, just not as good since I filled up most of the phone's internal storage (temporarily).

Sent from my LG-LG870 using Tapatalk 2

As others have stated, you do trade a bit of storage and RAM for the benefits of ART. Some people are claiming more benefit, others are claiming none, and I've seen a few saying things are worse on ART. As with any other fairly major change, track your usage patterns, battery life, screen on time etc before AND after for a few days to see how things settle in. For me, my usage patterns changed somewhat around the time I switched to ART, but in-use does seem a lot easier on battery. Standby I would say is about even. Biggest thing is to let it settle in a few days.

Oh yeah, and make sure you've got a good chunk of time when you do the switch. ART has to re-compile everything and it takes a LOT longer switching to ART then it does switching back. On my Gnex with approx 150 apps it takes a good 20 minutes. On Dalvik it takes slightly less then half that. Not a bad thing, just don't try to make the switch when you're in a rush somewhere.