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Task Killer Query


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  1. Bob Maxey

    Bob Maxey Well-Known Member This Topic's Starter

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    Some of you warn against Task Killers. For many reasons I do not agree with and a few that I do agree with. One person told me that you waste battery life running task killers and I am not so sure the amount of power it takes to close an app is all that big.

    So this AM, my phone slowed down. Was not sure why, so I ran a Task Killer and I discovered that some of the apps I ran earlier are still running. The music app, a wallpaper app, the Market, camera, gmail, and one other.

    This happens, or so I think, because I open an app and hit the Home key rather than back out of the app using the back key.

    Feel free to correct me, if this is not how it works.

    So my general query is: some of you say to delete task killers, but what if you have lots of apps loaded (and you do not intend them to run after you are done with them) and it affects performance? What other way is there to kill running apps without using the dreaded task killer?


    Bob Maxey
     

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  2. BookLover

    BookLover Well-Known Member

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    I posted this reply in a previous thread about Task Killers.

    It helped me to understand TKs and Android much better.

    HTH
     
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  3. w_bovine

    w_bovine Well-Known Member

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    Have you read either of these? I think they explain the situation well enough.

    Android Task Killers Explained: What They Do and Why You Shouldn't Use Them

    FAQ: Why You Shouldn’t Be Using a Task Killer with Android

    For the most part, you don't need to kill apps. As you pointed out, it's better to back out of an app than hit the home button.

    Android phones are basically very small computers; rebooting once in a while can be a good thing.

    I've had to use a task killer maybe 2 in the 3 months I've had an Android phone, and those times were for whacking an app that wasn't behaving well.
     
  4. X10iUser

    X10iUser Well-Known Member

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    Bob Maxey likes this.
  5. w_bovine

    w_bovine Well-Known Member

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    Perhaps. I don't care if someone uses a task killer or not. I tend to side with my own experience and that of the dev's and even the people responsible for writing Android in the first place.
     
  6. grainysand

    grainysand Well-Known Member

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    Android engineers from Google and people like Cyanogen have given their "opinion" that task killers are unnecessary. I'm going to take the view of experienced coders over that of random posters, if it's all the same to you.

    Froyo has a built-in task manager if you really have to close a misbehaving app, anyway. People who hit that "kill all" button in a task killer app are maniacs who are making their battery life much worse.
     
  7. X10iUser

    X10iUser Well-Known Member

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    Perhaps I don't care if others care. Do you see how irrelevant that comment is. :rolleyes:

    Kind of agreeing with what I said, it's personal preference. I use one as I have longer battery life.

    And that is all is isn't it, an opinion, so until I see some kind of scientific test results, I'l stick with my opinion and continue to use one as my battery last longer with one.

    Makes absolutely no difference whatsoever to me what you do or don't. And I'll take my actual experience of using one if it's all the same to you. :rolleyes:

     
  8. Bob Maxey

    Bob Maxey Well-Known Member This Topic's Starter

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    OK, you know and I do not. BTW, to me, you are a random poster and as far as I am concerned, you are just one more voice telling me a TK is bad. Please, I mean no offence; 'tis the general problem with the Internet. Everyone has an opinion and from the perspective of a clueless new Android user, your opinion is just as valid (or invalid) as one that says a TK is Heaven Sent.

    Can you provide a link to exactly what these engineers from Google have to say? I went to Google's Android Developers Web Site to look for info on Task Killers and so far, I find nothing. I AM NOT saying you are making it up, just want to know.

    I think it would be interesting to see some actual numbers. Saying a TK wastes energy without any specific test results is useless. Perhaps there are some sources of actual test results would be far more useful than a bunch of rather unscientific opinions. If a TK wastes energy, then I need to (or would like to) know exactly how much energy is wasted when I kill an app.

    Again, I do not know and I do not see how occasionally killing a few misbehaving apps wastes an appreciable amount of battery life. Numbers will tell the tale; if they are large, then I'll stop using one. All I know is those who say that a TK must never be used are fools because sometimes, you do not have a choice.

    Bob Maxey
     
  9. X10iUser

    X10iUser Well-Known Member

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    +1
     
  10. grainysand

    grainysand Well-Known Member

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    The opinion of people who know the OS much better than you. There's a reason I put quotes around "opinion"--it's an informed "opinion" versus an uneducated one. Unless, of course, you're also a software engineer/experienced Android dev who compiles the OS from source and makes heavy modifications to it, perhaps? Well, are you?

    I'm quoting the so-called opinions of experienced software engineers/coders who build ROMs by compiling Android from the source. Huge difference.

    'Kay.

    Android Developers Blog: Multitasking the Android Way

    http://androinica-serve.s3.amazonaws.com/wp-content/uploads/2010/05/cyanogen-task-killer.png

    Bolding mine. So, yeah, the opinion of random forum posters who can't tell an adb command from HTML code vs. someone who knows Android inside and out and has been doing innovative things to/with the OS since the G1? Go ahead, take your pick.

    The simplified explanation is this: Android manages its own tasks and allocates memory as necessary. However, because you likely have active processes always--widgets, gmail listening for push, SMS app listening for new texts--those processes should be allowed to run all the time, for very obvious reasons. You hit that cute "Kill all" button, and you kill everything. Including your launcher. Now, since presumably you don't proceed to uninstall all widgets and abstain from using Google services for the rest of your phone's natural life, those processes will restart right up. This is where the battery drains come in--it takes more power, so to speak, to start apps again than letting them become active as it is necessary. At this point, the phone slows down. The launcher has to be redrawn. None of the necessary apps you just killed will stay dead, because the OS needs them. Killing all tasks, therefore, is nothing less than unbridled idiocy.
     
  11. Bob Maxey

    Bob Maxey Well-Known Member This Topic's Starter

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    Which uses more energy:

    The extra processing time required to open another application because there are a dozen running apps, or using a task killer?

    Seems to me, if the phone's microprocessor requires more energy to do its thing, that extra amount of energy might be saved if there were no running applications. Is that saved energy greater than what a TK would require?

    Bob Maxey
     
  12. X10iUser

    X10iUser Well-Known Member

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    No, I'm a user, I'm a user that finds using a TK extends my battery life, don't know what your issue is or why you can't grasp that for a lot of people the practice actually contradicts the theory, which is the point I was making about the comments sections of such articles being full of users saying the same. If you don't want to use one, don't, but my personal preference is to, which is what I said to begin with.
     
  13. BookLover

    BookLover Well-Known Member

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    I actually look at it a little differently.

    If we believe that Android OS was written to handle memory well (unlike Microsofts OS), then I would think, we could be doing harm to the Android "innards" which could translate in the long run to a phone that has a shorter life span.

    I admit I know NOTHING about the Android OS (very comfortable with WinMo), BUT I believe what I have read in terms of it handling resources well (and differently than WinMo), so I believe that it is safer to let the Android OS run the way it was written than to try to interfere and causing probs later that I have no clue how to fix.

    I fall on the side that I'd rather have the phone have the longest lifespan it can versus having a few extra hours of battery per day. Of course, I can say this because I can top off my phone while at work. For those of you who travel or use it for school, this would be tough...So I'd invest in an extra battery, were I in that situation, rather than do something to a phone that could have unforeseen consequences.

    Long way to say "Better safe than sorry."
     
  14. lunatic59

    lunatic59 Moderati ergo sum Moderator

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    You are confusing active in memory with using processor cycles. Keeping an app open [at least a properly coded one] uses zero processor cycles until called to perform its particular function. Killing an app requires processor cycles to kill it, restart it as well as those ultimately used to perform its function.

    Look at it this way ... you park your car in front of your house and leave it there, engine off, waiting to drive to work in the morning. The neighborhood watch decides it is restricting traffic and has it towed to a lot on the corner. When you need to go to work in the morning you must walk to the lot and get your car ... drive back to your house to get your briefcase and then go to work instead of just getting in your car and going.
     
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  15. BookLover

    BookLover Well-Known Member

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    Great analogy. Thank you!

    To add to the analogy above, with Android, the parked car is OFF. With WinMo, the parked car is IDLING. Hence TKs are good for WinMo because the TK is shutting off an idling car. With Android, since the parked car is off, it isn't using any juice.
     
  16. Bob Maxey

    Bob Maxey Well-Known Member This Topic's Starter

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    Thanks for the links.

    But, I can exclude apps that are not to be killed from the TK. And yes, I agree that some apps need to run all the time. But, here is a problem many of us new to Android share: the accuracy of information is often questionable and some of us scratch our heads because we read conflicting answers. Some people simply take what is posted and it becomes a guiding principal in their Android Life; always quoted, and never actually verified.

    At least you posted useful links that I must take as gospel because the developers at Google know more than I know. At least for now :). I'll trust you, because you posted the links and your answer implies some measure of knowledge.

    I am the first to accept and admit my Android ignorance. Until I learn more, I am at the mercy of experts arguing about this or that; useless from the perspective of someone that wants to learn. I hope you can appreciate my position: when faced with two different answers to the same question, I can't assume the more logical answer is the correct answer. I think perhaps it is time to ignore both answers and do a little due diligence.

    Especially when you can read as many posts in support of a TK as against a TK. When us users want to know about something, we ask questions and we get arguments and opposing opinions and quite often, not many facts.

    I write technical documentation. I did so for Megahertz, USRobotics, 3Com, and Manufacturing Services Limited; I do so now, for several hardware manufacturers. My focus was Palm Pilots and my specialty was the Palm VII Wireless. So I am not totally clueless about the technical side of things.

    As a new user, I want to know as much as I can. That is why from my perspective, just saying it is so without numbers or a clear explanation of how Android functions is useless. Some of us are technically minded and we get more use out of a long list of numbers and technical explanations that we get from one man's opinion, repeatedly quoted.

    At our manufacturing facility, more than once, some engineer was wrong about how the product he designed actually worked. Observation backed up with numbers convinced him he needed to go to school. At least about Palm Devices.

    I'll assume you are correct but I'll stick with my strategy because occasionally killing an app is required. When an app refuses to behave, I'll simply kill it. I'll use the red 'back arrow' to properly back out of an app I do not need and I will kill apps that fill my memory and "seem to" slow down my phone. No offence to you personally and please do not consider this post to be an argument. I am just so bloody frustrated at just how much contradictory information exists. With all things Android and just about any possible question you ask Mr. Google.

    The links you provided will help me because the info comes from the horse's mouth, so to say. Or rather, the Robot's mouth.

    Bob Maxey
     
  17. lunatic59

    lunatic59 Moderati ergo sum Moderator

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    And one further note ... if you have the task killer to auto kill apps on the list that are required by the OS it's like paying the neighbor's kid to go get your car from the lot every time it's towed to the corner. Once he does, the neighborhood watch shows up again with the tow truck, all night long, wasting gas and wearing out your tires until you go to work.
     
  18. takeshi

    takeshi Well-Known Member

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    (nm)
     
  19. Bob Maxey

    Bob Maxey Well-Known Member This Topic's Starter

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    Perhaps I am confused. So let me ask my clumsily worded question in a slightly different way. Again, not arguing with you, just trying to understand. I am starting to get it.

    Right now, and according to my TK, there are 11 programs running on my Zio. Rather, they are just sitting there, consuming no power and bothering not a single soul. As I understand it, and from your explanation, the processor is not processing so battery life is conserved and all is well. The apps are just sitting there waiting to be called forth and not a single processor cycle is spent regardless of how many applications are loaded, and zero battery power is required to keep the apps loaded. Press my TK icon, and energy is spent closing the applications and I would have saved my battery if I just let it be. Is that correct so far?

    So my Zio sits on my desk, lots of loaded apps, screen is off, I am eating my chocolate coconut cream pie, reading the forum, and not one bit of energy is wasted. Hit the TK and poof, there goes some juice. Wasted juice and not needed.

    Suppose I decide to surf YouTube and drool over the ever so lovely Celtic Women. I load the application, but this time, it takes noticeably longer for the app to load. And I will be the first one to admit that it might not take longer, it might simply seem that way because we are discussing battery life.

    I will assume that the processor starts running when I press the little YouTube icon. Right? I mean, it must run and therefore, it requires energy from the battery. Forget that I am watching video; the act of pressing the YouTube icon causes the processor to run. Lots of loaded apps means perhaps it runs a little longer than it would with no loaded apps. Correct so far?

    So my question is this: assuming that some of my battery is used to fire up the processor in order to load YouTube, and further assume that the processor time would be slightly reduced if nothing else was loaded into memory, is the extra time required for processor cycles greater or less than than the battery life expended when I kill my apps with a task killer? I mean, my PC is slower if I have a dozen apps loaded.

    What am I still missing? Do lots of loaded apps require the processor to work harder when yet another app is loaded? Or can I have 30 apps loaded and when I load another, the time required for app 31 to load the same as it would be if no other apps were loaded.

    Cheers

    Bob Maxey
     
  20. takeshi

    takeshi Well-Known Member

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    Nothing wrong with that. Task killers do have their place. The backlash against them has been a bit blindly promoted as "task killers are evil" which is drastic oversimplification of the matter. Just be aware that a task killer can only address symptoms and not the real problem (the misbehaving app).

    You should really be looking at CPU usage for performance issues like this.

    I think you're overlooking CPU utilization.


    ^ ...and this. This is the real power-related issue with task killers. Endlessly killing something that starts up automatically makes for power consumption that is no longer negligible. This is why many people see an improvement in battery life after removing an auto task killer.
     
  21. lunatic59

    lunatic59 Moderati ergo sum Moderator

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    Yup. Pretty close, although unless the power is completely off, there is always *some* processor activity. The phone must sit there and listen for calls and SMS and whatever notifications it's allowed to listen for.

    That pie can be pretty heavy. It will take some serious juice to lift that fork. As for the phone, the screens and the radios are the biggest juice hogs.

    If you've killed it, then it does have to reload it, however if you have the YouTube widget on one of your screens, it may have loaded it already and the time differential is as you suspect, only perception. Don't forget, that the YouTube app needs to connect to the YouTube servers to draw the current list of videos, so the lag might be re-establishing the WiFi or 3G connection after waking up.

    Ah, here is where you start to falter. Android has a hierarchical memory management scheme. There are must-run services that will restart if you kill them which will be given priority and then it tries to rank your apps, and I may be wrong on this one, but the greater the frequency of access the higher priority Android assigns the app. It tries to keep as much in memory as possible since unused memory=wasted memory. Anyway, you fire up those lovely Celtic videos (I'll let your psychiatrist handle the subtopics) and the app needs to load. Android determines the space needed and then dumps apps in reverse order of priority and loads the YouTube app. That app will stay in memory until another app is launched and there aren't any lower priority apps in state.

    That small amount of processor cycles needed to open memory before the YouTube app loads is negligible as far as battery life is concerned. You'd have to load 20 apps in a row to even use close to the juice the screen uses per second ... and it wouldn't slow the app launch at all. Okay, maybe a few milliseconds. Count to ten milliseconds for me and you'll see what I mean.

    Now, you have to stop thinking in PC terms. Memory management is a different model. When Android needs more memory for an app, it dumps low priority apps, as in push the handle and watch them swirl away. A PC will swap out the active memory page files to virtual memory saved on your hard disk, which is several orders of magnitude slower than RAM. And, if those applications are used, the pages files are loading back into RAM after enough RAM is freed by swapping other pages files to disk. That's why more RAM in a PC (or Mac) always means better responsiveness if you run a lot of applications.

    You can have 30 apps in memory and when you launch the next one that isn't yet there, the lowest priority app will be pushed out to make room, taking much less power and processor cycles that it would take to launch your TK and kill enough apps to make room.
     

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