Otherwise known as "Why Newer Android Phones Don't Need Task Killers".
This is straight ASCII cut-and-paste from my Evernote page, so any spelling and grammar mistakes are mine. I have looked over various apps such as AutoKiller, Advanced Task Killer, various threads on memory management in Android, even a few bits of Android source code. I know about compcache, minfree, swap, kernel, and more.
This is aimed at an Android owner who knows the basics, but is trying to optimize their device. They may have experimented with ROMs and kernels based on recommendations, but don't know about serious internal tweaking.
I realize what I wrote will probably have the techies screaming "no, no, that's not quite right"... That's why I want a tech review. If I had committed any serious misunderstandings, please let me know. If you have more references, please list them. Would prefer a bit more detailed comments than "sucks" or "great".
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Memory Management in Android: the myths and the facts
Introduction
The Android OS, now at V2.3 "Gingerbread", is widely misunderstood, due to lack of hardware specifications and the open nature of system, has created a wide set of myths regarding how the memory is managed, and how one can best achieve good performance on an Android device.
This article will attempt to explain just how Android OS manages memory, dispel some myths regarding Android memory, and show you some techniques that will help you keep your system running smoothly while achieving good performance.
However, first, here's some technical stuff about Android memory and applications. Trust me, all this is necessary to understand how the whole thing works.
Android OS Memory Management Basics
Android OS, as of V2.2 (and 2.3) have two general types of memory: internal storage (sometimes known as application stroage), and SD card (which may be flash memory that works like SD card, but not physical SD card, such as in the Nexus S)
All apps (in the form of APKs) are loaded into internal storage. Each program can also request additional space as "data" and/or "cache".
All apps (in the form of APKs) are loaded into "app storage" part of the "ROM" (actually flash RAM). Part of the ROM is the boot ROM which loads the system. The other half of the ROM is "app storage". For example, in Motorola Droid, 256MB is RAM, and 512MB is ROM. Out of 512MB ROM, 256MB is Android System itself (actually a bit less), and the rest is "app storage", to max of 256MB.
With Android 2.2 and "Move2SD", a portion of the APK can be moved onto the "SD card", but main portion must remain in internal app storage. The size of the main portion that stays would depend on the app. Some apps cannot be moved or will not function if moved. "Protected" apps cannot be moved. Apps that primarily consist of a service and a widget may not work if moved. add Services or widgets needed for startup should not be moved.
For example, If you have a 256MB system (shows as 262MB due to 1024 vs. 1000 KB size difference) and have 130MB of apps and data/cache loaded, then that leaves about 130MB for the system to actually RUN programs. That sounds like a lot, but in reality that is not enough, since the system itself takes 50-80MB, and services will take up another 30-50MB, leaving almost nothing.
addedIn a 256MB RAM phone such as my Moto Droid, AutoKiller shows...
acore : 4.55MB (system)
dialer: 8.95MB (system)
system: 20.38MB (system)
autokiller:5.68MB
messaging: 3.41MB (system)
Swiftkey: 6.59MB
JuiceDefender 4.14MB
Calendar Storage 4.1 MB (system)
acore: 7.7MB (different pid) (system)
smart taskbar 3.81 MB
seePU 3.44MB
Screebl 4.38MB
SetCPU: 3.83MB
ATK Froyo 3.01MB
gapps: 7.79MB (system)
and 2 more at 4.66MB and 3.56MB
That adds up to... 99.88, or 100 MB.
But that is supposed to leave 156MB, right? Wrong. The system itself takes about 100 MB by itself, in addition to loaded programs, according to this thread about T-Mobile G1 (which has 192 MB of RAM, and has about 96000 KB after booting)
UPDATE: I found an article that explains how to read "MEMINFO". You can get MEMINFO app, or if you have SetCPU the overclocking widget it shows MEMINFO as well. Mine says roughly:
MemTotal: 231740 KB, or 226MB
MemFree: 3376
Buffers 272
Cache: 34960
SwapCache: 0
So the system (before OS kernel) uses about 30MB leaving about 226 MB
Cache itself used another 35 MB. , leaving about 189 MB
Minus 100 MB of auto-loaded apps, and you get... 89 MB.
If you run any programs that need more than that, programs and services will be killed to make room.
(see Redhat's explanation on what meminfo is supposed to mean)
SIDEBAR: native vs. Dalvik
There are two types of Android programs... "Native" programs, and VM programs.
Native programs are written for the specific CPU in the machine. While this gives better performance, this is much harder to achieve, so most people write program for the VM, or "Virtual Machine".
A "virtual machine" is basically a CPU emulator. You feed it a program, and it will run this program, as if it's a real CPU. The good thing about using a VM is it doesn't matter what the actual physical CPU the device uses. You write the program once, and never have to worry about converting it to other CPUs.
Android's VM is called Dalvik, and it is similar to Java's virtual machine. (In fact, Sun/Oracle sued Google for violating Java copyrights on JVM)
Different pieces of a single app
Most apps have either just an activity, or activity along with a service.
"Activity" is basically the user interface that takes your inputs and displays something back. Foreground app would be an activity.
"Service" is a background program that updates something. Common services includes input, widget updates, mail notification, and so on. Other services include Bluetooth, network updates, and so on.
(Actually there are two more types: broadcast receiver, and content provider, but those are not that pertinent to our discussion)
An app can use a widget, and the widget can use a lot of memory, usually several MB at once. You can see the different services and how much memory they are taking under Settings / Applications / Manage Services
How Services Use Memory
As explained above, Android OS have to run programs from within the limited space available, which, on older phones, isn't much. From within that much memory, it needs system work space to load all the services (you probably have a dozen loaded, taking up at least 30 MB) System itself uses about 60-70 MB (acore, phone, gapps, messaging, etc.) That's 100 MB used. That doesn't leave much memory for anything else, if you have 100 MB of apps loaded. (256-100-100=56) 100MB for system itself, about 100MB used for apps and services, and you got almost nothing left.
If you look at the services screen, at the bottom, there's a bar: red, yellow, and green. There is a number in the red section and some in green. Your services adds up to the number in the green section. The yellow portion is some memory that can be freed. The red stuff are system stuff and can't be moved.
What Happens When System Runs Out of Memory
When the system needs to load programs, but don't see enough available, it will start killing programs and services (to the system, they are all considered "process") from memory based on the following priority:
Empty App: the app is in standby, not being used, but is still in memory. These can be killed without any effect.
Content Provider: process that provides content to the foreground, such as "contacts content provider", "calendar content provider", and so on. Various "storage" are also content providers. Those can be restarted when needed.
Hidden Application: apps not visible, but still running in the background. These are not exactly running, so killing them should have no serious consequences.
Secondary server: services that stay in background and apps such as Launcher (or other home replacements). Most services go here, like music player, clock updater, background sync, and so on, that's not built into the OS. If these are killed there may be some problems, such as the playback is interrupted, background sync stops, widget no longer updates, and so on.
Visible app: the app is running and visible, but due to multi-tasking or such is not currently "on top". Any program with a display in the notification area is considered "visible". Android OS will not kill these programs unless absolutely necessary, but it can happen.
Foreground app: you see this app on screen, currently running, but also includes the system itself and "phone". These are never killed. In any case, system and phone have much higher priority than any app to make sure those are never killed.
Each category above has a certain number associated with it, sometimes known as a "minfree" value (in either "pages" or megabytes, depending on the app). When Android OS free memory drops below the minfree value for that category, apps in that category are killed. The killing starts Empty App group as that has the highest number. if that's not enough, it then starts killing apps in the Content Provider Group, and it keeps going until it has finally freed up enough memory to load the app and all related processes (such as services).
NOTE: Having a constant "notification" in the notification area makes the program "visible app" instead of "hidden app", thus making it less likely to be killed by the system to make room for other apps.
A lot of problems with Android device occur when the system tries to make room by killing "secondary server" processes that are needed. Playback of audio (music or podcast) stopped, download stopped, location services stopped... etc. This especially happens on phones with little RAM. First Android phone, T-Mobile G1 / HTC Magic, has 192MB of RAM. Moto Droid have 256MB of RAM. Second generation of Android phones, like HTC Wildfire, got 384MB of RAM. Recent phones, like Droid X, Galaxy S, and so on got 512MB.
NOTE: Some apps, like web browser, can exit but still save the URL you were browsing. So when the process reloads, it is almost as if it was never unloaded. Unfortunately not all apps can do that.
So what is the solution?
There are two approaches to the problem: make more memory available, or pre-empt the auto-kill by killing apps yourself.
Making More Memory Available
There are four ways to make more memory available short of exchanging the phone for a more powerful one.
1) Free up more app storage / internal storage
Either uninstall the apps altogether, or move2sd as much as possible. Keep in mind move2SD may not work for all apps, and amount that can be freed varies greatly. Uninstall an app is best, as it both frees up the space itself takes, and if it loads a service, that service is loaded either, saving even more space.
While it's true that the app that wasn't run won't take up any space, every widget is served by a service, and a small app can load a HUGE service by calling existing libraries and declare a large buffer for downloads. And just because you don't actually use the app doesn't mean the system will not load it. The only way to make sure the app will NOT be loaded is to uninstall it (or if you have Titanium Backup premium, you can "freeze" the app)
2) VMHeap
VMHeap adjusts the the amount of memory that can be dedicated to the Dalvik Virtual Machine (VM). In general this should not be touched, and does not really make more memory available. It is available only for experimentation purposes.
This usually is NOT tweakable without mod ROM such as Cyanogen Mod. And benefits are unproven so far. Don't change anything yet.
3) CompCache
CompCache, or "compressed cache", is handled by the Linux kernel. It takes a portion of your memory, and use it as a cache space, but compressed. By using on-the-fly compression it is able to make your memory appear to be a bit larger than it actually is. However, the result is slower performance.
This is usually NOT tweakble without mod ROM such as Cyanogen Mod. The kernel also must support this feature, and not all do. This also slows your phone.
4) Swap file or partition
Linux kernel allows the OS to use the SD card as swap space by either creating a swap file or a swap partition. This adds a lot of read/write action to your SD card and may substantially decrease its usable life. However, it is a reliable way to "add" a lot of memory to your system.
Root access is required to swap the kernel, and the kernel must support this feature as well. Not all do. This really slows your phone. Beware.
Pre-emptive Killing of Tasks
The other way to avoid auto-kill is to kill the processes yourself via an app, so the auto-kill is not triggered. This is why apps like Advanced Task Killer and all the other "task killers" are created.
Basically, the task killers automate the task of killing apps, so it will free up memory thus auto-kill is NOT triggered. And because Task Killers have ignore lists, you can add your specific app to be ignored, and hopefully it will still run.
The best known one is ATK (advanced task killer) by ReChild, but there are plenty of others on the market. They usually have tweakable settings, like killing apps every time the screen is turned off (eeks!) or just at timed intervals (every 30 minutes), and so on.
On a phone with 512MB (or more) of memory, there should be no need for task killers, as the phone should not run out of memory. On phones with 256MB or less of memory, ATK may be necessary to keep the phone "free" for other apps.
Recommended Actions
If you have one of the older phones with little memory (256MB or less), load only the bare minimum of apps you need. uninstall the rest. You need to minimize your memory usage as much as possible to leave as much space for the apps. Keep 100-150MB available for the system is best. After system and services loaded, there should be at least 50MB left to load other programs and such.
You can use archivers like Titanium Backup or AppMonster to archive the apps to SDcard, and only reactivate them when you need them. Or you can delete them altogether, only redownload them from the Market when you need them. This will even work for purchased apps.
You can also purchase Titanium Backup which allow you to "freeze" apps, which makes leaves them in memory but NOT loaded. You can also uninstall built-in apps that you don't use, such as Amazon MP3, saving even more space.
If that is not enough. you can try using CompCache and/or Swap. However, those are not exactly recommended, and thus are only methods of last resort if you can't kill enough apps to matter. Try 18% compcache or even 26% compcache. If that doesn't help, try 128MB swap, or even 256MB swap if that still doesn't help.
For phones with 384MB or more RAM, you should not have to be so stingy, but no need to overload either. With extra 128MB -384MB you can load extra 50-100MB of apps and a few more services. The idea is still to keep 100-200MB available (depending on the phone). You do not need task killers and all that.
I was looking on the explanation for OOM priorities, and there it is. Thanks. I'm wondering why there are no replies to this thread. Oh wait, it's a question.
thanks for the most awaiting tutorial abt RAM.n yes i was wonderng y this thread hasnt got applause...
Delete and disable unnecessary apps
You can do this by using the app manager in your settings, or by long-pressing apps in your drawer and dragging them to the “Uninstall” section.
Clear the cache data
The issue is that cache can build up and become pretty heavy on your smartphone’s internal storage. Try to clear it from time to time, as it can also get old. The option is available for individual apps through the app manager, or you can look for a cache cleaning application in the Google Play Store.
Clean your device storage
Got too much music, videos and other files around? Filling up your internal storage can affect performance, so try to keep your phone memory as tidy as possible. Go through all your files and decide what you will actually use and what is just taking up space for no good reason.
Get rid of widgets!
Try to limit your widget usage as much as possible. Of course, don’t sacrifice your whole experience either; after all, widgets are among of the coolest things the Android OS offers. Just keep it limited to what you will actually take advantage of.
Dump the live wallpaper
Live wallpapers sure are fun, but they affect performance and battery life. Unless you are willing to sacrifice a bit for those fancy animations, just go grab a regular image.
Keep your phone’s software up to date
Make sure your phone’s software is always on the latest version available.
Rooting?
If you really want to go nuts and unlock the door to a whole other series of possibilities, you can root your phone. Once you get total access to your device you can install cleaner ROMs that will keep your phone running smoother. It’s even possible to overclock the processor and make it work extra hard for you, hence making the phone faster.
Perform a factory data reset!
The option is in your phone’s settings under “Backup and reset”. There’s also ways to do a factory reset using the recovery menu, but the steps are different for every phone. Google is your friend!
When you've had a smartphone for a while it can start to feel slow, and RAM — random access memory, which is where your phone stores its stuff as it's using it — can be part of the problem. If your phone doesn't have enough RAM it can struggle, but there are ways to address that. You can even create extra RAM without cracking the case or reaching for a soldering iron.
Find out how to increase your smartphone's RAM right here!
How to fix phone lag on Android
Android Lollipop tips and tricks
What is RAM (Random Access Memory)?
RAM is what your device uses when it's doing something. For example, when you're editing a photo both the photo and the app you're using to edit it are in the device's RAM; when you finish editing the photo is then saved to your device's storage so it can't get lost. The more RAM you have the more you can do, so for example you can have more browser tabs open, more apps running or more system features doing their stuff.
The problem with RAM is that it isn't always emptied properly, and apps don't always behave. Some apps and system processes run when you don't need them to, and others don't clean up after themselves when they quit. After a while those issues can produce noticeable results such as slow performance, lagging and stuttering, and the odd crash.
Like internal storage, RAM is a physical component of your device so you can't just stick more in. What you can do, though, is use it more efficiently — or use some clever tricks to create RAM from other kinds of storage.
RAM — shown here in desktop form — is physically limited in every device. Unlike PCs, you can't just stick more memory into your phone or tablet. / © Taringa
How to increase your RAM without root access
Now that you know what RAM is, we'll show you how to preserve it. In this first part, we focus on tips for non-rooted devices. For those devices you can't magically add more memory, but you can make better use of what you've got. As a rule of thumb, the more your phone is doing the more RAM is being used, so if you can reduce what's running you can free up more memory for the tasks that really matter.
Limit widgets and live wallpapers
Widgets and live wallpapers are both pretty greedy when it comes to RAM usage. Many refresh often and occupy bandwidth, while some are continuously active. This can also cause your battery to drain faster. So remember to limit the number of them in effect to optimize your current available memory.
Animated wallpapers can take up a lot of RAM.
How to root your phone without voiding the warranty.
Disable applications
Some applications take up RAM even if they aren't currently being used, so you're getting all the downsides of unnecessary RAM use without anything to show for it. Organizing which apps should and should not be running in the background can take time, but it's worth it to improve your smartphone performance.
To disable an application, go to Settings and then Apps or Application Manager. Next, go to the All tab to get the list of all the applications currently on your device. To disable an application, tap on it, then tap Disable and confirm. Be careful not to disable everything and anything, unless you want to end up with an unstable system, but most apps that don't come pre-installed on your handset are pretty safe to disable (or delete entirely if you never use them).
Head to your device settings menu, then the apps page.
Next, tap on the app you wish to disable and tap Disable.
Disable animations
Animations often steal RAM and are quite inessential; you can manage these in the developer options. To enable Developer Options on your device, go to your Settings, then About Phone and then tap on the build number about seven times until it notifies you that you have become a developer. (Please note that this has no negative effect on your device, it just adds the developer options menu in your settings. You just need
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tra_dax
Nice copy pasta
This is straight off Android Pit
HMpenguinify said:
This is straight off Android Pit
Click to expand...
Click to collapse
Yeah it is not even copied completely. The text is missing the last part
Why don't you post something from your own experience or your own thought, please don't copy from other sites.
I think it's called ram optimization and not increasing the ram. BTW.
max24328 said:
I think it's called ram optimization and not increasing the ram. BTW.
Click to expand...
Click to collapse
https://play.google.com/store/apps/details?id=com.swapit.expander.de&hl=en
Can't post from other sources without due credit. Thread closed.
Also given lower post count of OP, this is potentially posted to increase post count.
Hey guys , does anyone know any app that can monitor rooted phone (s8 exynos) on background . Every heat , every app behavior , any abnormal changes , speeds , anything. I know there are plenty of apps for that , but after downloading plenty , couldn't p pin point the one I need.
I use Simple Sytem Monitor.
It can monitor Ram, Network, Disk Activity, CPU Usage, CPU Frequencies(Graph and Time), Temps ans Battery Temps. Can run in background, prevent screen off while in app. Test read/write speed, floating windows etc
You can also list running processes and sort them from RAM Usage, CPU Usage, Network Usage, Network speed, Name, PID, UID etc. It even features a Kill process as root.
Amazing for finding out high CPU/Memory using apps, even lists system apps ?
Exzu said:
I use Simple Sytem Monitor.
It can monitor Ram, Network, Disk Activity, CPU Usage, CPU Frequencies(Graph and Time), Temps ans Battery Temps. Can run in background, prevent screen off while in app. Test read/write speed, floating windows etc
You can also list running processes and sort them from RAM Usage, CPU Usage, Network Usage, Network speed, Name, PID, UID etc. It even features a Kill process as root.
Amazing for finding out high CPU/Memory using apps, even lists system apps ?
Click to expand...
Click to collapse
Thanks mat