[Galaxy Tab 2 (Unified 7" + 10.1") Android Developm] Luebbi:
First impressions with my GT-P3110

Hello everybody,

just thought to spend a holiday to my own fun and gave the package a try. My golden oldie (P3110) had a long second spring with a ressurection remix Marshmallow image.

So I flashed the image some 36 hours ago (along with GApps nano package) and want to contribute collected impressions. At first there has been a "wow", the ROM feels faster than any customised package I ever flashed to the Tab. After the installation of some twenty apps in a binge I experienced the same phenomenons others report, a constant lag and battery drain which can only described as horrible.

I have a theory (it's more a belief since I'm merely an advanced amateur - sad but true), but before entering details I must thank you Andi for spending a good portion of your leisure to explore the limits of this outdated device. I hope this helps to locate the trouble.

Excourse:

Beside the fact our little Tab is driven by a SoC that -on marketing papers- can't compete even to entry-level rivals I can not accept it's not sufficient to handle general activities on Nougat. Within this Thread there came up an argument about the RAM as bottleneck. It is neglectable, sources like phonedb tell the OMAP has LPDDR2 (400MHz) interface which isn't quite THAT bottleneck compared to LPDDR3 memory on newer devices: Taken the frequency beside it's still a matter of how wide the memory is connected. The OMAP drives RAM 64 Bits wide while all these entry-level SoCs like from Mediatek use LPDDR3 - but just 32 Bits wide, which results in half the (theoretical) Bandwidth, even at higher clocks one will not experience a difference at all in real world memory performance between the OMAP and these "Nougat-ready" SoCs, at same clocks the OMAP should even outperform them due to a 2x higher memory bandwith, nothing these crippled SoCs with 32 Bit controller can compensate through higher memory clocks even in theory.

So, even in Theory the OMAP should be sufficient to drive the ROM. In real world performance we all may have experienced it, a fast system right after first start. So we come to the point what's it up with "lagging". Within the time after flashing I found my Tab quite warm all the time and a simple CPU monitor testified my suspicion, the OMAP just never entered deep sleep and idle states, running with at least 600 MHz or 1 GHz all the time. So we experience no "lag" because the OMAP is lacking power, it's rather a lag coming caused by a hogged CPU and there must be a responsible activity or process in background.

On my device the the following services run constantly (or better real time):

Equalizer -> SystemService

AOSP keyboard

Android Services -> Notification Ranking Services (App rights management)

Play Services: Any except CastPersistentService. Was quite surprised to find OutgoingSMSListenerService active.

In Battery stats my Tab is constantly active, also I see cellular network unavailable but active. Before the battery drained last night one of the processes with highest consume was "configuring mobile network". Actual battery drain is 10 % in 40 minutes, I started it fully loaded right before writing these lines.

To sum up my personal suspicion, the Play Services on my GT-P3110 expects a cellular network or it's final configuration to set up the Play APIs, therefore the App rights management (I'm not sure, but the entry for telephony should not be there on the wifi-only variant, should it?) is waiting for the story to be finished and they hog the CPU until the tasks are finished - which will most likely never happen on a wifi-only device :D . Just don't know why AOSP keyboard and Equalizer stay active in real time, I will deactivate/replace them first and report about the changes in hogging and battery drain. The Play Services usually eat a good part of CPU time, but I can not recall a moment I watched them running in real time on any Droid device I owned.

Greetings, Luebbi