ubuntu-phone team mailing list archive

[รัชนันท์ ศรีรัตนเมธ <peathot@xxxxxxxxxxx>]

Hello,

I port Ubuntu Touch to LG L90 Dual which has 1 GB of memory. This means 
I also suffer from all problems about memory people have with BQ Aquaris 
4.5. Being somewhat experienced with the system, I believe that the 
problem happens from at least 2 reasons:

1.Management of suspended application's process and Ubuntu touch's usage 
of lowmemorykiller. For those unfamiliar with Android's lowmemorykiller, 
it's mechanism used for selecting which process to kill under low memory 
situation using some parameter like oom_adj value and memory usage of 
that process.
In Android, oom_adj for each process is computed (by ActivityManager) 
from how important that process is, what application is using that 
process, how recent that application was suspended, etc. As far as I 
know, Android adjust oom_adj so that recently suspended application will 
have lower oom_adj (less likely to be killed), at least for 
just-suspended application. I'm not the specialist though, so please 
correct me if I'm wrong.
In Ubuntu touch, I have no idea where oom_adj is computed. (Please 
anyone tell me?) But from my experiment, all suspended applications have 
the same value of oom_adj. How this affects the problem? Imagine this:
 * A few application using not much memory is suspended.
 * You launch a web browser, which, of course, use significant memory.
 * Then, you swipe the web browser into the background and launch 
Dekko. Dekko also uses significant memory.
 * Now, lowmemorykiller kicks in and decide which process should be 
killed. Ideally, it should kill those not recently used first. But, as 
all suspended application have same oom_adj value, lowmemorykiller have 
to decide what to kill by its memory usage, and, as you might guess, the 
candidate is the web browser.
I believe that if lowmemorykiller kills processes in first point, there 
will be enough memory for the web browser and Dekko.
I also believe that this causes one of the bug I observed on my phone. 
It's about having browser killed while waiting for a picture from 
gallery app. Have a look at 
[https://bugs.launchpad.net/ubuntu-application-lifecycle/+bug/1596059]. 
If people using BQ 4.5 can reproduce this bug, please upvote the bug by 
clicking "Does this bugs affects you?" on top of the page.

2.Ubuntu touch's choice for using QML. Out of curiosity, I opened an SSH 
session, ran "top", and looked at the calculator app's memory usage on 
my phone. I found out it's around 113 MB. 113 MB just for a caculator!? 
I'm speechless.
I believe this can be reduced somehow. One of the idea is that, as many 
QML component in Ubuntu is shipped as source .qml files, I understand 
that each application will have to load those files, parse that files, 
and keep those parsed code individually in each application's memory 
(please correct me if I'm wrong). As many Android kernel has enabled KSM 
(kernel samepage merging), maybe we should try exploiting it? I've tried 
enabling KSM on my device, but the result was pretty disappointing. 
Maybe we should mark those memory as mergeable?

Sorry for a rather long e-mail, but I just want to share my though about 
how low memory situation could be resolved. Maybe all I've said is a 
crap, then please give me the correct knowledge.

Ratchanan Srirattanamet

PS. It seems like browser session won't restore after being killed in 
background on my device. Does it works on other device? rc-proposed 
build 20160715-092035.
On 16/07/2559 16:31, Simplehuman wrote:
> I'm Meizu MX4 user with 2 GB of RAM on rc-proposed. Problems are the 
> same as you described
>
> 15.07.2016 23:26, Eran Benjamin пишет:
> > I get the same in BQ4.5, and it does seem to be happening more since 
> > OTA11, I cannot run two "heavy" apps without other apps exiting.
> >
> > Apps just become some bad res jpeg of their last screen view, which 
> > gets refreshed when I click on the app again.
> >
> > I also assumed it's mem limitation, but are we sure it's a ram issue 
> > and not how the OS handles multiple apps?
> >
> > Right now my SIM card is in the BQ, but I have to rely many times on 
> > a tag-along tethered android phone for basic daily tasks, for 
> > example: The BQ can either play music to my car stereo via bluetooth, 
> > or run unav without getting stuck mid route, not both.
> >
> > I got a vanilla install with only Daniel Wood's Owncloud-sync extra 
> > (the mem issues were before the extra app was installed).
> >
> > Am also curious to hear Meizu owners if more ram solves it.
> >
> > Is getting Ubuntu touch to run on a rooted android phone a complex 
> > operation? Does it have to be from specific chipsets?
> >
> > Eran
> >
> > On 15-07-16 18:53, Wayne Ward wrote:
> > > I'm looking at maybe getting rid of the e5 as the what I think is 
> > > low memory is driving me mad! I'm thinking this has one gig of ram 
> > > and its not enough? It used to be but now always seems to be low on 
> > > memory.
> > > I have a clean install with the following installed and obviously 
> > > running in background
> > >
> > > Rockwork
> > > Owncloud
> > > Now i have dekko running unconfined for email notifications to pebble
> > > And sometimes music appeared open all the time to play from pebble 
> > > when I want.
> > >
> > > The problem is I get reload on facebook, browser, gmail or twitter 
> > > and dekko just closes itself when it feels like it. It only started 
> > > doing this since say ota10.
> > >
> > > I noticed the meizu has 3 gig of ram. I'm just wondering if meizu 
> > > users get the same problem as they have more memory?
> > > I really love my bqe5 but its getting annoying now to be honest. 
> > > Don't want to switch back to android, been here from the beggining, 
> > > cant use unav as that just white screens after 5 or 10 mins as well
> > >
> > > In my mind more memory is required or am I wrong and all the phones 
> > > do the same.. I dont mind shelling on a new meizu as long as I get 
> > > rid of this nigly problem thats just stoping me enjoying the phone 
> > > and OS I love and got used to now ?
> > >
> > > Is there maybe away to streamline the E5 phone like turn of a 
> > > upatart app any suggestions please its wearing thin now, specially 
> > > after todays proposed updated killed my phone and wiped it just to 
> > > get the same reload problem
> > > I can video this and put it on my blog if anybody needs to see what 
> > > I mean...
> > >
> > > Wayne