Help with zram, how much, when is it needed

[Shawn Eastman]

Ok, I am not sure if this is the perfect place or not for this thread and I have found very little infor on this subject so I will start a thread here. I have the aforementioned tablet and I love it.

For more info in case it is relevant, I flashed clockworkmod recovery, replaced the bootloader, and installed cyanogenmod 10.2 stable (android 4.3). I also have installed pimp my rom (dangerous but worth it, make sure you have backed up your device) and enabled so many tweaks i cant count, most noteably the i/o tweaks that seemed to help with the i/o issue asus has.

I noticed that my ram is 1gb, and that when just cold booting and going to settings that about half my ram is used. I started looking into this because when operating an intensive program like lecturenotes that when i go back to my home screen the wall paper is gone. A reboot solves this issue.

So my questions are could zram help the slight lag and wall paper issue?

What, if any, would optimal settings be for zram? I am looking for a general rule of thumb like with 1gb ram it is good to have 10% of it zram.

Is 1gb of ram still valid or is it slightly behind these days?


I know that zram has some very exceptional uses where it excells, like on my motorola cliq from 2009, it greatly helped that phone that had 256 mb ram (maxed zram at 28%) run android cyanogedmod 7.2 (gingerbread) when the device originally came with cupcake (android 1.5). Zram also helps my mothers Linux box with a mere 1.5 gigs ram, but on my computer with 8 gigs ram, it has no use.

 

[Shawn Eastman]

On a side note I then installed ARC: redux from the integra zone app. I had all the settings set to defaut, but since this game is made for tegra devices I attempted to bump the graphics a bit, I recieved a low memory warning with zram set to 26% and in both these cases the game reverted to the low settings aftarward. I then went into the settings menu and set zram to 18% (marked as default, even tho zram wasn't initially enabled). The game now works on medium settings with no memory warning and the performance has no noticeable impact (except better quality).

 

[Shawn Eastman]

some stats to the "free" command in terminal: (with 18% zram,)

Total used free shared buffers
mem: 960556 960556 33392 0 128
+/-buffers 960428 33520 - -
swap: 178908 27984 150924 - -

Sorry the text doesnt appear the way I wrote it, with zram enabled so far in my light testing i havent seen it go over 33000 for used swap, that is not a lot, but it is still used to some extent. When I set zram to 26% swap was about 256mb in size if i am reading it correctly. The game also gave the low memory error and defaulted to the low settings for graphics at zram set to 26%. I will some more testing and post the results.

It seems that because zram is being used in some cases (like booting up) there is some benefit to have it enabled and on, however becasue it isn't used a lot, setting the higher amounts would be detrimental.

it seems 10% is just fine for an occasional need (sets swap at about 100mb), but with this device off is ok.

On my motorola cliq (from 2009) was 256 mb ram, zram(or compcache back then) helped give it new life and i gave it the highest setting. This was helpful because with the limited ram, zram extended the ram by virtual means at some very slight cost to processor performance. The asus transformer infinity tf700t (terga 3) has 1gb ram, thus for this game that is enough ram to run at highest settings and i have zram at 10%. Zrams use on this machine is limited because the hardware is enough to begin with for all the applications i have tried, but because it does recieve some use, I would recomend 10%.