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Apple Executive Confirms: Manually Quitting Apps Doesn't Improve Battery Life (bgr.com) 151

An anonymous reader writes: Apple software engineering VP Craig Federighi recently dispelled one of the more long-standing myths about iPhone battery life. In short, if you spend a few minutes every day double clicking the iPhone home button and manually closing up applications in an effort to maintain battery life, you're wasting your time. The reality is that the applications you see upon opening up the multitasking pane are actually nothing more than static images intended to represent a list of your most recently used applications. Apple support documents have indicated, "generally, there's no need to force an app to close unless it's unresponsive." Apple support docs further explain: "After you switch to a different app, some apps run for a short period of time before they're set to a suspended state. Apps that are in a suspended state aren't actively in use, open, or taking up system resources."
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Apple Executive Confirms: Manually Quitting Apps Doesn't Improve Battery Life

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  • Waze (Score:5, Informative)

    by Chmarr ( 18662 ) on Thursday March 10, 2016 @05:11PM (#51674541)

    Except Waze... Waze is a battery hog. I always quit that as soon as I'm done with its navigation features.

    • Re:Waze (Score:5, Informative)

      by MightyMartian ( 840721 ) on Thursday March 10, 2016 @05:22PM (#51674607) Journal

      And Facebook, an app that just eats cycles and battery life on both iOS and Android. That such a major player as Facebook writes such a shitty awful resource hogging app frankly shocks me... until I remember iTunes on Windows.

      • Re: (Score:3, Interesting)

        by Anonymous Coward

        It's been proven that deleting Facebook improves the performance of other apps [smh.com.au]. It's actually worse than it seems.

      • Re:Waze (Score:5, Insightful)

        by pr0fessor ( 1940368 ) on Thursday March 10, 2016 @05:42PM (#51674711)

        This is one of those instances where they forget that there are some apps that actually do continue in the background and that they are really popular.

      • Re:Waze (Score:5, Insightful)

        by ShanghaiBill ( 739463 ) on Thursday March 10, 2016 @05:43PM (#51674717)

        That such a major player as Facebook writes such a shitty awful resource hogging app frankly shocks me...

        It should not shock you. Big companies write some of the worst apps. If a small company makes a crappy app, they are out of business. But a big company doesn't have much at stake. So they design by committee, and their coders and QA are not even on the same continent. I have an Amazon Echo, and their Alexa app is one of the worst I have ever seen. Every time it wakes up, it spends several minutes spinning the "pinwheel of death" ... just to display the shopping list. Then while I am getting the orange juice, it goes back to sleep, and I have to wait again before I can get the next item. It is so painful to use that I just open the list once and copy it onto a piece of paper.

        • ... It should not shock you. Big companies write some of the worst apps. If a small company makes a crappy app, they are out of business. But a big company doesn't have much at stake ...

          In the years of yore, if you buy IBM you wouldn't get fired. It might even got you promoted

          No matter how clunky, how useless, how bloated IBM's products were, many people (then) somehow equate IBM to 'excellence'

          Same line of thinking is happening with brand names such as Facebook / Tweeter / Google

          People can't seem to realize that they are continually duping themselves because of a certain 'brand names'

        • That's not quite fair to the Alexa app, which is basically just a web view that hits their API servers. It's only 2.2MB in size. So while yes, it's very slow, that's more on the backend team than on the app developers. ("But cache everything so it displays faster!", but then you have cache invalidation issues, and set reconciliation problems why two people modify their locally cached versions of lists, etc. at the same time.)

          • That's not quite fair to the Alexa app

            Designing the backend is part of the process, so that is no excuse. A grocery list is just a few hundred bytes. I cannot imagine why it should take 2 full minutes to download it, even when connected to my home WiFi at 50Mbps. The quality and speed of the network seems to make no difference. It is always slow. Using cached data from days ago may not be best, but it doesn't even used cached data from 30 seconds ago, and will refetch data (using an algorithm slower than carrier pigeons) every time it wake

      • by Anonymous Coward

        I just use the Facebook mobile site. It's actually MORE functional than the app 'cause you dont need that Messenger garbage. And the performance is obviously 100000x better.

      • Re: (Score:2, Funny)

        by Anonymous Coward

        I'm sure Facebook's "engineers" will fix that problem right away...as soon as they find the right snippet on stackexchange to copypaste.

      • Re:Waze (Score:5, Informative)

        by EvilSS ( 557649 ) on Thursday March 10, 2016 @06:00PM (#51674835)

        And Facebook, an app that just eats cycles and battery life on both iOS and Android. That such a major player as Facebook writes such a shitty awful resource hogging app frankly shocks me... until I remember iTunes on Windows.

        Facebook was actually caught cheating once by playing inaudible audio to prevent iOS from putting it into sleep.

        • Re:Waze (Score:5, Informative)

          by 93 Escort Wagon ( 326346 ) on Thursday March 10, 2016 @07:45PM (#51675229)

          Facebook was actually caught cheating once by playing inaudible audio to prevent iOS from putting it into sleep.

          "Once" was just a few months ago. Their patch to fix this issue went out on October 22, 2015.

        • Re:Waze (Score:5, Informative)

          by BarbaraHudson ( 3785311 ) <barbara.jane.hud ... minus physicist> on Thursday March 10, 2016 @07:46PM (#51675241) Journal

          On Androd:

          • System
          • Data usage
          • Turn off cellular data
          • Scroll down to the evil app (facebook)
          • Touch the app's icon
          • Turn off background data

          Now the app won't be running except when it's in the foreground. You won't chew through your cellular data plan, and you won't get an alert when somebody in Oz posts while you're asleep.

          Cell data will still work for the app when it's in the foreground, so problem solved.

          • Re: (Score:3, Insightful)

            by vux984 ( 928602 )

            Why not go all the way and just uninstall it completely.

            Then check it once daily from a laptop... then once weekly, then go 6 months go by and you realize you haven't checked it, and your life isn't any less full. You log in and see a grotesque display of human narcissism, drama, separated by advertising and more advertising and then logout again never to return...

          • You won't chew through your cellular data plan, and you won't get an alert when somebody in Oz posts while you're asleep.

            If a bunch of notifications can "chew through your cellular data plan" then you have far bigger problems with your phone.

            • It's not the notifications, it's the constant pinging of their servers that chews it up. Cut out the backgrounds stuff and data usage drops by at least 80%, maybe more.
              • it's the constant pinging of their servers that chews it up.

                Yeah no you still have a major problem on your hands. I say this as someone who for several years had a smartphone with a 200MB dataplan and did nothing to limit apps from talking in the background.

                Unless you're roaming then the data charges from background activity are not an issue unless you have a horribly broken piece of software or have done something stupid like not told Google Play to update only on wifi or something like that. Background services from Facebook, Instragram, whatsapp, etc use next to

                • Let me beat your anecdote with real life. Before I disabled background activity, Facebook was chewing 500 meg. Disabled it, dropped by more than half.
                  • Let me beat your anecdote with real life. Before I disabled background activity, Facebook was chewing 500 meg. Disabled it, dropped by more than half.

                    An anecdote is what you're providing. Real life is that there's hundreds of millions of Facebook installations on phones including on phones with very very anaemic data plans and it's a non issue.

                    I'm not saying you're wrong, just that you have a problem. YOU. Your specific version of Facebook installed on your specific phone has a problem. Facebook notifications, chats and continuous connection do not even remotely use 500meg. The content does not download beyond the first few lines of text for display on n

      • And Facebook, an app that just eats cycles and battery life on both iOS and Android. That such a major player as Facebook writes such a shitty awful resource hogging app frankly shocks me... until I remember iTunes on Windows.

        iTunes still compares favourably with the steaming pile of shit that is Samsung Kies.

      • I finally gave up and went back to the web interface. It has improved to the point that the App is not really necessary, and it doesn't eat 140MB of precious flash.

      • And Facebook, an app that just eats cycles and battery life on both iOS and Android.

        Exactly...how can an app like Facebook that does constant background queries and refreshes not use more battery power than when it's off or disabled??

      • Facebook is why I rooted my phone so I could delete it, almost doubled my battery life. Plus that there is no way to block the "Facebook calls" that go right to the phone even if you don't have your number in FB...after getting calls from people I never gave my number to...bye bye!
      • And Facebook, an app that just eats cycles and battery life on both iOS and Android. That such a major player as Facebook writes such a shitty awful resource hogging app frankly shocks me... until I remember iTunes on Windows.

        Oh I very much doubt it's an accident at all. Facebook makes their living off gathering information from its users, aggregating, and selling/advertising. I can guarantee that's at least partially if not entirely why their app is "resource hogging".

      • I deleted the Facebook app from my phone and my battery life tripled. Just stopping the app didn't seem to have any effect.

    • Re:Waze (Score:5, Interesting)

      by LordKronos ( 470910 ) on Thursday March 10, 2016 @05:38PM (#51674681)

      Exactly, and there's other apps too. I don't recall if it was in another slashdot discussion or somewhere else, but this topic came up recently and someone pointed to some sort of documentation or other official info on the matter. The gist of it was that apps only have a limited (short) amount of time to run in the background, and then they are forced to shut down. It then went on to say that certain apps that have permissions for certain things can continue to run.

      So in summary, apps are not allowed to continue running in the background....unless they are allowed to do so. Which makes the entire argument of "you don't have to manually close them" complete bullshit. Maybe you don't need to for MOST apps, but there are still plenty that do have the permission to continue running.

      • Re:Waze (Score:5, Informative)

        by tlhIngan ( 30335 ) <slashdot&worf,net> on Thursday March 10, 2016 @06:18PM (#51674917)

        Exactly, and there's other apps too. I don't recall if it was in another slashdot discussion or somewhere else, but this topic came up recently and someone pointed to some sort of documentation or other official info on the matter. The gist of it was that apps only have a limited (short) amount of time to run in the background, and then they are forced to shut down. It then went on to say that certain apps that have permissions for certain things can continue to run.

        So in summary, apps are not allowed to continue running in the background....unless they are allowed to do so. Which makes the entire argument of "you don't have to manually close them" complete bullshit. Maybe you don't need to for MOST apps, but there are still plenty that do have the permission to continue running.

        Apps get around 5 minutes to finish off what they're doing. That's it.

        The exceptions would be apps that need to be running in the background - e.g., audio players, navigation apps and VoIP apps.

        Audio players are obvious - it would be quite annoying if you put your Spotify or Pandora or the music player or other thing in the background only to have the music stop. Navigation apps are similar - you need to be alerted when you get close. (Waze and other apps also have to keep the GPS active, so it's a double hit on the battery). And VoIP/IM apps need to be active to keep you signed in.

        Those are the general classes of apps that can keep background processing. Some apps, like Facebook cheat - they open an audio stream and then play silence, keeping them alive because iOS thinks its a media player app.

        Navigation apps can't cheat as they reveal GPS usage.

        • I remember piano and synth apps that would kill battery life (way back when when I actually used an iOS device). But the assertion of the Apple guy seems tantamount to an assertion that apps which continue running in the background don't use the battery. I don't buy that.

      • Exactly, and there's other apps too.

        Dropbox was the worst battery hog I have ever seen. Constantly updating active folders and wasting battery and bandwidth.

        There are other well-known reasons to not use Dropbox. (HINT: They index every file that passes through their system. And so many businesses share pre-Patent-Disclosure stuff for their projects there. Not to mention many other sensitive documents.)

        My University has banned any and all Faculty use of DropBox for anything Uni-related.

  • by Anonymous Coward
    Apps in suspended state very much do use up system resources. Maybe not the CPU, but they'll use up the RAM.
    • Apps in suspended state very much do use up system resources. Maybe not the CPU, but they'll use up the RAM.

      Yes, but clearing the RAM takes more resources and more power than leaving it as is.

      • Is this a real statement? Doing a free() is basically just flipping a few bits. There might be a bit of housekeeping involved too but, it's not such an expensive operation in this context that it should be avoided.

        (And, I apologize in advance if I have just been whooshed)

        • Comment removed based on user account deletion
          • by Dunbal ( 464142 ) *
            That depends on the OS. We've moved on from the days when memory taken off and put back on the heap is fragmented and can't be assigned until it's the largest remaining chunk again.
          • Ok, sure, in that context, I definitely agree. Free memory is underutilized memory. And, if it's treated like a traditional disposable cache, then, yeah, explicitly clearing it is unlikely to give you the desired results. I just felt a bit confused in that the GP seemed to indicate that the act of freeing the memory was an expensive operation.

        • by imgod2u ( 812837 )

          Only if the app was in a state of being shut down. If it's suspended, there are potentially a lot of cleanup necessary to do a "closing" of the program. Not to mention if you go back to the app, you have to launch it again -- using CPU cycles.

          It also isn't guaranteed that it remains in DRAM instead of being paged to flash.

      • Depends on how smart your memory controller is. Unused RAM doesn't need to be strobed. If everything in use lives on one chip, why bother sending electrons to the other chips until you need them?

    • Re:FALSE (Score:4, Insightful)

      by alvinrod ( 889928 ) on Thursday March 10, 2016 @05:20PM (#51674593)
      Which the OS will automatically free up as necessary by killing off suspended processes. Why waste your own time doing it when it offers no real benefit and the OS will free up the memory as soon as it needs it anyhow?
      • by rsborg ( 111459 )

        Which the OS will automatically free up as necessary by killing off suspended processes. Why waste your own time doing it when it offers no real benefit and the OS will free up the memory as soon as it needs it anyhow?

        Problem is some apps are persistent. It's like removing Skype from your tasktray if you're going into an airplane - no need for that app to constantly poll.

        Plus Waze essentially tracks you all the time (not just when you're asking it to navigate) - best to keep that shit off unless you're using it.

        • by Anonymous Coward

          Problem is some apps are persistent. It's like removing Skype from your tasktray if you're going into an airplane - no need for that app to constantly poll.

          No, they're not. On iOS, no application is allowed to stay permanently resident in RAM and immune from jetsam.

          Some processes (system deamons, foreground applications etc) are given higher priority to keep in RAM than others, but all of them are vulnerable, and will be kicked out should the RAM be needed.

          • No, they're not. On iOS, no application is allowed to stay permanently resident in RAM and immune from jetsam.

            If they've been set as "allowed" to update in the background, they essentially can.

            On my iPhone 6 Plus, within the last 6-12 months I've had multiple occasions where I'd be sitting at home in the evening, and a pop-up window would open saying something along the lines of "Waze is still accessing your location information - do you want to let that continue?"

      • On an iPad2 with newest iOS, several resource hungry apps will NOT be able to run unless you manually go in and remove all apps from the list.
        That's with several gb free, so it seems very likely that some RAM must be used.
    • Re: (Score:2, Informative)

      by Dunbal ( 464142 ) *
      The days of shortages of RAM are long gone. Unfortunately because it makes modern coders sloppy. But RAM is the least of your worries unless you're doing something crazy or have a huge memory leak problem.
  • Not always true (Score:4, Insightful)

    by vampirbg ( 1092525 ) on Thursday March 10, 2016 @05:13PM (#51674563)
    This is for regular apps. Apps that have background mode enabled can run in background and can consume CPU cycles. They can even use GPS, WiFi, LTE etc. That consumes battery. Most of the running or GPS apps run just fine in background. Otherwise they'd just stop recording once the screen locks or, worse, keep the screen on at all times.
    • Apps that have a reason to run in the background are not the ones people are killing. At least not the people who don't immediately post the followup question: why don't I get facebook notifications when I quit facebook!

  • by danbob999 ( 2490674 ) on Thursday March 10, 2016 @05:32PM (#51674655)

    This was by far the most common myth about smartphone battery life I heard. The next one is to turn off GPS after use to save battery (as if it changed anything when not using an application using the GPS)

    • by Chmarr ( 18662 )

      Well, at least on the iphone you get the little arrow thing when there's an app using location services.

      • Exactly, Android has the same. Disabling the GPS is a privacy feature, not a power saving feature. Unless you want to browse maps for hours (then of course disabling GPS might actually save some power).

    • by Anonymous Coward

      Why wouldn't keeping the GPS on use power? It listens for GPS signals and keeps track of satellites so it constantly knows your location. This is good for when you start a GPS related app and it instantly knows your location as the phone has maintained GPS lock, but it does take some amount of power to do that.

      • by Anonymous Coward

        It sounds like you're describing wifi, GPS is shutdown since it can download/reload AGPS data almost instantly.
        Pretty much all smartphones have internet-assisted GPS and leaving it on indoors would be useless.

    • Re:GPS is next (Score:5, Informative)

      by dbIII ( 701233 ) on Thursday March 10, 2016 @07:46PM (#51675239)
      Wifi on the other hand. I get more than three days run time on my slightly aged phone with wifi off and less than a day with it on.
  • Heh. (Score:2, Insightful)

    It's kinda funny, actually. The reason the iPhone didn't originally support mutli-tasking is battery life. Now that it does support it, even after going through the extremes they have to keep it lightweight, people still preemptively kill battery hoggish apps.

    Apple did try to warn us.

    • Re: (Score:2, Informative)

      by AmiMoJo ( 196126 )

      Actually the reason the original iPhone didn't multitask was that it was so underpowered. 400MHz single core CPU and just 128MB of RAM. Remember that at first it didn't even have third party apps, and when they did come along they were very limited in what they were allowed to do in order to preserve the user experience in such a low power, low memory environment.

      At the time Android allowed multitasking but needed more powerful hardware and even then performance was quite poor. It certainly wasn't as slick

      • by adolf ( 21054 )

        Actually I was multitasking pretty well on a first-gen iPod Touch back in the day.

        No big deal.

        Never ascribe to hardware limitations that which can be adequately explained by the presence of Apple's marketing department.

      • Actually the reason the original iPhone didn't multitask was that it was so underpowered. 400MHz single core CPU and just 128MB of RAM.

        And yet the Android phones coming out years later supported multitasking but had much weaker CPUs. Of course their performance and battery time sucked,.

  • The battery part is true. I am really impressed with iDevice standby battery life.

    But the static image thing.. if that were true that all you are seeing in the task list is basically nothing more than the shortcuts to your recently running apps then that would mean that every time you switch to another app the first app would close. I know this is not the case because app state is preserved when you switch back to the app, even days later.

    In addition, sometimes when switching back to an app, it won't functi

    • by radish ( 98371 ) on Thursday March 10, 2016 @06:21PM (#51674935) Homepage

      Apps which are put to the background are allowed to run for a little while to let them finish up what they were doing (e.g. saving something). Then they're suspended - their state is written to disk and they're flushed from memory. The screenshot is saved so you can see it in the list, and if you reopen it the app will be restarted from the saved state.

      Apps can register themselves as requiring to run full time in the background, examples are navigators, messaging apps, etc. These will not be suspended, and can eat the battery. If you add one of those flags to your app without actually having justification to do so, you'll be rejected from the app store.

      • Apps which are put to the background are allowed to run for a little while to let them finish up what they were doing (e.g. saving something). Then they're suspended - their state is written to disk and they're flushed from memory.

        Except if the the app is a messaging app, social network app, GPS using app, audio playing app, app that downloads anything or any other of the most common types of apps which all needs to and are allowed to keep running in th background.

    • This is true. Words With Friends will stop playing audio, and must be manually closed and reopened to fix it.
  • Any app that posts alerts or responds quickly based on location services or provides motion telemetry is pretty much burning battery, however.

    Want to save power drain? Only allow location services to apps that need it all the time, and don't allow apps to update tracking on their icons (e.g. mail, texts, etc) unless you really want it.

    And set battery to power conservation.

    Push all apps you don't actually need to the cloud (delete).

    That said, Twitter has no setting to disable internal pics and vids for it's

    • Push all apps you don't actually need to the cloud (delete).

      "Storing your apps in the cloud" and deleting the local copy is stupid. It takes time and energy to upload them, and more to download them each time you want to use them.

  • I'd be more likely to believe it if one of their devs told me.
  • Audio streaming apps (especially ones that are live streaming like TuneIn, etc.) seem to try and continue buffering the stream after you disconnect bluetooth or unplug the headphones. I don't dislike that feature, but it can really kill your battery if you, say, shut off your car and just grab your phone then go inside a building with little to no cell coverage. That few minutes of the cell radio struggling to maintain the audio stream under poor RF conditions can chew through some battery very quickly.

    So

    • Why an Apple executive would even waste his breath telling people not to force-close apps is beyond me.

      A user emailed Tim Cook with the question, who forwarded it to Federighi for a response.

  • by BrookHarty ( 9119 ) on Thursday March 10, 2016 @06:14PM (#51674893) Journal

    Everyone is listing off apps that do suck cpu cycles. So apple is wrong about this. So is google. We keep getting these explanation from these vendors which doesnt seem to match real world experiences. Thats because vendors use imaginary scenarios, static apps that dont use resources like gps, cpu or network in the background, which is fine for a game, but reporting apps use cycles.

    Google goes even farther and says task killers DECREASE battery life, because the task killer will run often. Total bullshit, but as its easy to test and see the results.

    I think think the vendors are using unrealistic use cases, apple and google thinks the average use will just call/text and brows the web, so all other apps are a "rare" thing so its excluded.

    • by GuB-42 ( 2483988 )

      The reason task killers can decrease battery life on Android is that when an app subscribed to an event and isn't running, it is started. So the task killer may cause the app to be regularly restarted instead of just staying in memory.
      Task killers only help with buggy apps that can sometimes go crazy instead of properly getting into standby.

      Some task killers are a bit better and can prevent apps from restarting. These can really improve your battery life, in exchange, you usually lose all background feature

  • by Anonymous Coward

    Quitting things _unequivocally_ makes these devices run better, particularly for video applications. There are far too many occasions where a video will simply not launch until other apps are closed, even 'suspended' ones.

  • I get "normal" battery usage out of my iPhone 4S, which is to say maybe a day if I happen to browse the web a bit, Facebook a bit, make a few calls. 2-3 days on very light usage. But on a recent trip to the US, where I had no cell service, my battery life utterly tanked. I could feel it getting hot in my pocket. My guess was that it was constantly searching for a cell signal it could use, and had ramped up the TX power to max to try and get one. When I twigged and turned off the cellphone feature, battery l
    • by rsborg ( 111459 )

      I get "normal" battery usage out of my iPhone 4S, which is to say maybe a day if I happen to browse the web a bit, Facebook a bit, make a few calls. 2-3 days on very light usage. But on a recent trip to the US, where I had no cell service, my battery life utterly tanked. I could feel it getting hot in my pocket. My guess was that it was constantly searching for a cell signal it could use, and had ramped up the TX power to max to try and get one. When I twigged and turned off the cellphone feature, battery life returned to normal.

      This suggests that if you are in a marginal signal area, your battery could be getting hammered because the phone tries harder to maintain a connection.

      Oh, that and the usual suspects - the Facebook app is terrible.

      Did you know you can simply shut off the cell/data portion of your phone? If you don't plan on getting signal where youre going, this is a wise choice. In my experience with T-Mobile, I get signal almost everywhere in Europe or Asia where I roamed (and I pay nothing for the data). But if you're not going to get signal just shut off the radio.

  • AFAIK iOS has a per App option to allow the App to access location always, never, or if the App is running. In the latter case quitting the App saves battery power if it is the only App using location because the phone no longer tries to determine it's location. Now, I could be wrong and this could be new information, maybe the phone always knows it's location and it is only passed to the App if the correct setting is selected. My own experience though is that setting Apps to only use location if running an

  • People double tap on the home button and see this massive list of apps stretching back to the dawn of time and what are they supposed to think?

    No-one is going to switch between their current app and one twenty deep in a list like this. It's far quicker to just go and relaunch the app.

    I'm not surprised that people think that they need to "kill off" the items on the list. Apple could solve this problem by rethinking the UX - one such solution would be to limit the items on the list and make clear which ones a

  • Wrong, they are caching junk to speed up loading the most recent apps. True, just like android, the os cycles stuff into the background pretty efficiently, it leaves junk in the cache. The ones in "suspended" mode are indeed using resources, just not enough to actually affect battery life in any noticeable way. The cache, on the otherhand, can get out of hand.
  • Apps that are in a suspended state aren't actively in use, open, or taking up system resources.

    How are they suspended, but not using system resources?

  • I know for a fact that this is wrong. I have a few exercise apps that I use at night. If I forget to manually shut them down, I find my iPhone is dead or nearly dead when I wake up in the morning.

    Also, when I first had my iPhone, I started opening all the apps to see what they do. I had no idea that they were still in the background. After a few days, I wondered why my battery was draining so quickly, to the point that I thought there might be something wrong with my iPhone. Then I discovered how to

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