App and Process Killers

K

Kunmui

New member
I hope this hasn't been covered anywhere and if it has please feel free to redirect me.

Can anyone clearly explain if Android really needs an app/task/process killer. All the blogs and reviewers seem to think it does but then the techies and developers who have a solid understanding of Linux say it doesn't.

I have been running my new N1 since last Wednesday and barely notice an occasional lag when returning to my home screen or swiping from screen to screen. I run Advanced Taskiller and close most stuff, leaving gmail, setting, voice-search, weather channel and task killer. This eliminates the lag.

Also, is there a difference between a task killer, that closes apps, and a process killer that ends software stuff that I don't know are running - I am by no means a tech guy, just a gadget guy.

I am looking forward to a clear answer, if there is one.

Thanks,
Dave
 
Well, yes and no.

The majority of people who think Android needs a task killer just don't understand how Android works. They may be correct in certain circumstances, but not for the reasons they think.

However, processes can and do use up memory, and lack of free memory does slow down Android.

The misconception comes from people thinking Android works like Windows. With Windows, if you have a program running in the background, it's taking up memory, and a (usually small) amount of processor power. As such, the more background tasks you have running, the less memory you have and the slower your PC gets. So, people have this idea that killing off processes is the way to go to speed stuff up.

Android works differently. With Android, a process can actually use almost 0 memory, and can really use 0 CPU. When a process or app stops, what can happen is the app saves its "state" (a bit like a snapshot of its memory, similar to how Windows hibernates, but this is just for one app). At this point it can be using almost no real memory. It will also use 0 CPU. When it's like this, it can be reloaded very quickly when certain events (called intents, on Android) happen. The advantage here = 0 CPU, almost 0 memory, quick loading.

If you kill off processes or apps you will end them completely. So, when Android sends out an intent like SMS_RECEIVED, and you've killed off your Messaging app, then the Messaging app will have to completely reload and initialise. This takes more time than if it had just had to reload its state (i.e. if it hadn't been killed). So, this is why killing processes is bad.

However, some apps do not save their state like this. So they take up huge amounts of memory. This slows down your phone if it's low on memory, and hence this is where task killers can help. This is because a lot of people who develop apps also have their Windows mindset in place.

In summary, if you kill a task, it will take longer to reload if it needs to run for any reason.

If you don't kill a task, it might or might not take up lots of memory, which might or might not slow your phone down, depending on the app and your free memory.

If you don't kill a task, the task will load and start quicker if you run it or Android needs to start it.

If you kill a task that runs automatically, or frequently, or is needed by Android, or by any other apps, then it'll just reload (taking CPU and using the memory you've just freed up) again in a short time.

The trick is to learn what apps/processes you and Android and your other apps need to use, and keep them running.
 
Wow, that is great answer, thank you sooooo much!



How can I tell if my app is a memory/battery/CPU killer? That info isn't usually found in the reviews in the market place. Is there something built into Android like Windows Task Manager? Or a reliable app in the market?
 
I don't know of any app that does this well. Advanced Task Manager can display how much memory an app is using, but it seems to not be the information we expect. For example, it shows 23KB being used by the browser. Yet, when I kill the Browser, it frees up 10MB of memory (434x as much)!

I use Advanced Task Manager. Among other things you can set up a list of apps to never kill. You can then tell it to automatically kill any others every X minutes, if you want. I don't use that feature. Instead if I feel like freeing up some memory I just go into the app and click "End All", which will kill all apps not in my exclude list.

I keep stuff in my include list that I know needs to run quickly like the Voice Caller ID app and the TTS Service which it needs to speak, or is handling stuff in the background (like email and gmail, battery widget, toggle settings, etc).

Anything you don't use much, or don't mind waiting an extra few seconds for it to load, and isn't used by anything else, is something you may want to consider killing. ShopSavvy is one such app, that runs from time to time in the background to get an update on your location, on the odd chance you want to check a price of something. In the meantime it's using your GPS (i.e. battery) and lots of memory.

Most things aren't CPU killers - other than obvious things like fasts action or graphics intensive games.

To check how much memory an app uses... well... I just judge this by killing the app with Advanced Task Manager and noting how much additional free mem I have listed at the bottom of the screen.
 
I prefer using a Task Killer. Cleans up my memory and I'm already using to having to do so since I'm coming from a Blackberry Storm.
 
it doesnt because the os does it when its 100% necessary, these apps just do it quicker to minimize lag. all task killing apps pretty much do the same thing.
 
I've never heard an explanation like Extorian's (thanks for that, btw), but even after the fact, I'm still probably going to use TasKiller, which I've been using for a while. And the way I use it would probably make some people /facepalm.

Within TasKiller, it tells me how much memory I have free (currently 39MB), and, of course, when opening up other apps, this number depletes to the 20s, never under 19. When it gets to this point, I'm not sure if the phone is actually sluggish or if the lower memory number is acting as some sort of placebo and just "tricking" me into feeling like the phone is going slower, but I usually end up killing everything not on my exclusion list. And now this is starting to sound like some Terminator human vs. robots thing, so I'll end it here.

Good luck
 
Try aTask Killer. It can show you CPU usage (total/user/system) and memory usage (total and for each process). You can see which processes/app use a lot of memory.
 
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