Database Develop

[Q] What is and how works VM heap?

Hi
Everybody talk about changing the VM heap value, but... what is the difference after changing it? What about increase its value? And decrease it?
On the CM7 thread adamz667 post this: http://forum.xda-developers.com/showpost.php?p=15065093&postcount=4569
Anyone can confirm that?
Thanks

Increasing cm heap means that apps can use more memory which makes them run faster but then since tbey use up more mem u will have less free memory.
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Here you got some definition:
VM Heap Size
The heap is an area of dynamic memory allocated to programs. With a larger heap size, there is more memory for the program and the garbage collector can run more efficiently. Therefore, it is possible to get better performance by setting a larger VM heap size.
However, if you set it too high, you can run out of free memory which can trigger swapping which will degrade performance. Therefore the VM setting is a trade-off.
The optimal value will depend on the RAM on the device as well as the programs and usage patterns, therefore the optimal setting can often only be determined by the user experimentally.
Default value: varies between devices
Click to expand...
Click to collapse
from: http://droidgram.com/forum/8-Android-Dalvik-VM-Heap-Size

adamz667 said:
Here you got some definition:
from: http://droidgram.com/forum/8-Android-Dalvik-VM-Heap-Size
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Click to collapse
Thanks adam, but your post on CM thread was a good theory and this definition it's opposite to your post (a this new one: http://forum.xda-developers.com/showpost.php?p=15092265&postcount=4582)
I only want to know what value use without have to try all of them during days of testing...
Thanks

parads said:
Thanks adam, but your post on CM thread was a good theory and this definition it's opposite to your post (a this new one: http://forum.xda-developers.com/showpost.php?p=15092265&postcount=4582)
I only want to know what value use without have to try all of them during days of testing...
Thanks
Click to expand...
Click to collapse
I have tested all of them today and the best results was with 16mb.
How I was testing it?
Shadow Guardian HD is a very heavy game for MM's ram memory. So I've tested every vm heap size on one and the same level of SGHD, with the same run environment and game was most playable on 16mb (no freezes, reboots, no returns to home screen).

Really 16mb. Which rom? And how far did you get in the game?
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thre3aces said:
Really 16mb. Which rom? And how far did you get in the game?
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I am using CM7rc10 (14.06.2011) I am now in 4th episode (level?) - Medusa Sanctuary.

That is very very interesting. I'm gonna have to give cm7 another chance. Maybe rc10 is a lot better than rc4 (last cm7 I tried)
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i also have good performance with 16m tried most settings from extremely large to extremely small...
also png optimized most apps again and again... (which decreased the size of the apps by almost 10mb again - quite sure that it does not make much of a difference)
don't have any app locked in memory and only one homescreen with adw ex without widgets...
dunno till now i have not experienced any issues with lost sms or phone calls...
but i'm aware of that it could happen with my settings so it needs more testing, jit turned off etc. phone works like a charm since i switched from froyomod a week ago or so.
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Are you sure u tried 16 mb. Because I just tried shadow guardian on cm7 rc10 with ur settings and zepplinrox supercharger on balance and tbh it was rather language at times
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I've tried jit off and VM heat on 16MB but not get any result.
The launcher was freezing 3 or 4 times, and all games get a minimal improve: 3 seconds more until FC.
I'm testing with: Asphalt 6 and Brothers In Arms 2 (Gameloft games) and Age of Wind v2.2. All versions for MM, with people that play them on stock rom.

thre3aces said:
Are you sure u tried 16 mb. Because I just tried shadow guardian on cm7 rc10 with ur settings and zepplinrox supercharger on balance and tbh it was rather language at times
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well as i said i do not use that memory intensive apps.
(i think my biggest apps are maps and the browser, and the browser barely goes beyond 30mb, so 2 vm's with 16mb, instead of 2 with 24. but most apps stay below 10mb so i think for my use it is a good solution)
also i debloated the rom massively and replaced most system apps with smaller ones.
cm7 performs very well with this settings, at least for me. (no redraws, no lags in ui no freezes etc...)
like i said i don't use games on my stone
edit: only genie news & weather app reloads often but i think it simply has a high priority.
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That is quite interesting. On ho no I
And 20mb with balanced 3 supercharger works great. But not so well on 16mb
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I had tried 16mb weeks ago when somebody suggested it.
That lasted about 5 minutes.
Scrolling between adw screens was brutally choppy.
Swipe finger, wait, look at watch, then bam - the screen suddenly decides to quickly jump to the next screen...

zeppelinrox said:
I had tried 16mb weeks ago when somebody suggested it.
That lasted about 5 minutes.
Scrolling between adw screens was brutally choppy.
Swipe finger, wait, look at watch, then bam - the screen suddenly decides to quickly jump to the next screen...
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I've got the same with 12mb vm heap. But when I use 16mb everything works fine on CM7 and HO!NO! CM7. Maybe it depends on rom/apps you use and your own configuration.

I guess.
But I'm used to fast, smooth and lots of free ram no matter what rom I'm using
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adamz667 said:
I've got the same with 12mb vm heap. But when I use 16mb everything works fine on CM7 and HO!NO! CM7. Maybe it depends on rom/apps you use and your own configuration.
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yeah 12mb is to small... experienced some errors with it too.
i have to say that for me everyhing between 16 and 32 mb seems to do not do much of a difference, but with 32mb my system uses some more RAM right after boot.
after a while it usally uses less (around 80-90mb sometimes less, sometimes more) so i normally have around 60mb free RAM, which seems to be enough.
i'm out of this discussion for now, but i have to say that i rly think ur VM Heap settings should match the apps u use.
so just try different settings.
@Zeppe
yay never experienced that, but i use only one Homescreen anyway. and ADWEX is rly memory friendly : )
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Changing heap size?

On the latest Go launcher ex beta there's the option to change heap size, with 128 being default, and 48 being 'recommended.' I have no idea what this is, but can it improve the phone performance, and does it come with any drawbacks/dangers? I tried setting it to the recommended 48 and the phone seems to be smoother but I'm not sure.
Also, how will battery life be affected?

I may be wrong but thats the java memory heap size the app will work with. Nothing major would happen if you change it.
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128 its perfcet for our 1 gb ram.
48 recommened for phones with 512 mb of ram.
Heap size its virtual bufer for your catch and other ****

[Q] Xperia x8 Swap

Hello. i use Alfs 8 kernel and rom Ginger Dx.
I use 128mb swap and with 20 swappiness. But what are swappiness?
And what are the best value?

HT::MOSTAR said:
Hello. i use Alfs 8 kernel and rom Ginger Dx.
I use 128mb swap and with 20 swappiness. But what are swappiness?
And what are the best value?
Click to expand...
Click to collapse
Swappiness refers to the tendency of the system to swap something into swap. Higher values mean that the system will swap more into swap, which also makes the phone slightly laggier as swapping and swap itself is slow as compared to ram. However higher swappiness will also result in more free ram.
Recommended values are 10 or 30.
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Ok i will set swappiness to 30.

Vm heap size for ace s5830i

what is the best vm heap size for a smooth and fast device.? Should it be high or low? I was shocked to see it at 64 by default..It has a total of only 290..
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High is better, try with this values: 96mb or 128mb, 128mb is better than 96mb but if on your device 128mb is too high and after go slow then use 96mb.

Large values are good with heavy apps but your lightweight apps will run slow. 24 is good for texting, surfing. 32 is a balance. 64 is the default stock, though there isn't such a need.
128 is too much.

consegregate said:
Large values are good with heavy apps but your lightweight apps will run slow. 24 is good for texting, surfing. 32 is a balance. 64 is the default stock, though there isn't such a need.
128 is too much.
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Click to collapse
No, high values are always better and instead low values as 24mb and 32mb slow down the device, read about the dalvik vm heap size for understand why.
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I have only 48 Max in my cyanogenmod rom. My default is 32. Apps are fast enough anyway.
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galaxyace152 said:
I have only 48 Max in my cyanogenmod rom. My default is 32. Apps are fast enough anyway.
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First your rom is custom then the value of dalvik vm heap size for you is different and depend from the settings of your rom, instead for stock rom's and stock settings from samsung 128mb is the best, currently i've setted 128mb on my galaxy mini and works perfect, but however i think that if you put 64mb rather than 32 on your rom surely works better, and as i've already said for understand why is better a high value need understand how works and what do the dalvik vm heap size, then read about the dalvik vm heap size (i already read and i know how works and what do the dalvik vm heap size).
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Increase RAM??

ok so i was thinking our mini has 384mb ram of which only 280 are available...is there some way to use the whole RAM not only 280mb??
on froyo i had: 279mb ram
on ginger: 280
on ics: 276mb
so why not 384?? whats holding the other 104 mb?

think i found what i was looking for: "MemTotal" = physical memory minus whatever is being shared with devices (such as the radio, DMA buffers, etc), so it will always be less than the advertised RAM for your phone.
am i right??

Use swap it will increase your ram but you must have a good sd card.
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hsay said:
Use swap it will increase your ram but you must have a good sd card.
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you mean a class 10 card? If so, how do I create a swap partition for my rooted device?

It's because some memory is also used for graphics and other stuff. In ICS it is 279MB, but on JB it's 276 because I have increased framebuffer size for triple buffering etc.. Theoretically, by experimenting, it's possible to get at least 285-290MB.

Me, too..
I have experimenting and the result :
Froyo : 281 MB
Ginger : 279 MB
IceCream : 278 MB
JellyBean : 276 MB
as far as i know, RAM used by :
1. GPU
2. Graphics thing
3. And Other stuff..
Then the rest of them goes to RAM values, so your Mini RAM was around 300 Megabytes, but since GPU, and other things take it RAM just decreased.
I also have a Galaxy Tab 2 7.0 Inc, wich have a 1 Gigabytes RAM, but since other things take it, it decreased into 679 MB (wow, really huge decreased isn't it ? :silly: )

xyboox said:
you mean a class 10 card? If so, how do I create a swap partition for my rooted device?
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Click to collapse
You can create a swap partition from cwm from advanced option then while partitioning SD card select a value for swap. This will completely erase your SD card so make a backup
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Good to know! Thanks @hsay
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