ubuntu-phone team mailing list archive

[Wayne Ward <info@xxxxxxxxxxxxxxx>]

Good morning guys :)

funny thing with the low memory
i left my phone in my pocket open yesterday which screwed my mobile
settings - i ended up zapping it as couldnt get mobile data to work!
put everything back as normal 
now i rockwork and owncloud sync installed 
and like to have dekko running unconfined and music app waiting to play
and thats it, i usually battle to keep these to open ..
last night i had these open and can usually open only one social media
app IE facebook, if i want to go on google + i have to close facebook
other wise i get this reload when im scrolling down
last night i had the music / dekko and facebook and google + working
perfect it was like the phone had a new lease of life!

I thought about it this morning, the only thing thats different on this
phone than my usual setups is i dont have ssh enabled to the phone?
Can that make a difference or has there been some changes over the past
few days, i am on proposed

Many thanks for any questions

Wayne  :)


On Wed, 2016-07-20 at 13:37 +0200, Eran Benjamin wrote:
> 
> 
> On 19-07-16 17:41, Gerry Boland wrote:
> > On 07/16/2016 08:48 PM, Thomas Voß wrote:
> > > On Sat, Jul 16, 2016 at 8:25 PM, รัชนันท์ ศรีรัตนเมธ
> > > <peathot@xxxxxxxxxxx> wrote:
> > <snip>
> > > > 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:
> > > You are almost right, but we are not using Android's
> > > lowmemorykiller, yet.
> > > Instead, we configure the vanilla OOM killer by altering
> > > oom_score_adj
> > > (oom_adj is deprecated).
> > > 
> > > Android's lowmemorykiller sits on top of this mechanism and
> > > allows for
> > > specifying ranges of memory
> > > and mappings to oom{_score}_adj values.
> > > 
> > > As you describe later, we are not yet deploying a heuristic that
> > > assigns a higher oom_score_adj value
> > > to app instances that have been used less recently (think about:
> > > least
> > > recently used is more likely to be killed under the assumption
> > > of a uniform distribution of memory usage). The respective
> > > feature is
> > > under development iirc, but I'll
> > > let Gerry and Ted comment on this explicitly (I CC'ed both of
> > > them explicitly).
> > Thomas is correct, while we're setting an OOM score to influence
> > the OOM
> > killer's decisions, we currently set the same OOM score for all
> > background apps, irrespective of how recently they were used.
> > 
> > We're now working on more advanced OOM score calculation, so that a
> > recently-used background app is less likely to be killed than one
> > used
> > less recently. This bug tracks that task:
> > https://bugs.launchpad.net/ubuntu/+source/ubuntu-app-launch/+bug/15
> > 79799
> > 
> > 
> > <snip>
> > > > 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?
> > > > 
> > > I think we should take the time and analyze memory usage first
> > > before
> > > starting to optimize.
> > > Specifically, for the reported 113 MB, is that RSS, USS or PSS?.
> > > I
> > > don't have a phone with ssh handy right now
> > > but I will try to reproduce your test case tomorrow first thing.
> > > I
> > > would start analyzing /proc/$pid/smaps first.
> > > 
> > > I would also propose to establish a memory baseline measurement
> > > by
> > > considering a very simple QML app just displaying a rectangle.
> > > That should give a reasonable baseline for comparisons. Even if
> > > the
> > > calculator is simple, it still puts its own app logic on top
> > > (stack of
> > > calculations etc.).
> > QML is a very easy language to use, but that has a consequence: it
> > is
> > easy to write code in a memory wasteful manner.
> > 
> > One can easily write code that loads all the views your application
> > will
> > ever have into memory - even though only one view is shown at a
> > time. It
> > just takes a little care to properly load/unload views to lower
> > your
> > memory use (using the UITK will help with that).
> > 
> > It is too easy to load big images into memory and scale them down
> > on the
> > GPU. Complex QML widgets can be expensive in memory too - the UITK
> > team
> > are working on rewrite existing QML widgets to be more efficient.
> > 
> > The sad truth is that when developing an application, monitoring
> > memory
> > usage is one of the last things thought of!
> > 
> > To address thing we're working on a performance monitoring system
> > to
> > give a high-level perspective on application resource usage
> > (CPU/memory/IO...), so we can quickly identify wasteful apps and
> > help
> > them improve. Watch this space!
> > 
> > Thanks for sharing your thoughts.
> > -Gerry
> > 
>  Is there a simple way (e.g. cli) to influence this OOM score metric?
> Let's say that the music app is my most important, but I do not bring
> it up often, can I manually give it some static priority in the
> decision making?
> 
> 
> 
> > 
> > 
>  
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