Workaround For Poor Ubuntu Phone Performance / Stuttering? "Touch The Screen A Lot"

[phoronix]

Phoronix: Workaround For Poor Ubuntu Phone Performance / Stuttering? "Touch The Screen A Lot"

Some Ubuntu developers are currently looking at poor performance of the Ubuntu Phone, particularly when it comes to stuttering or a poor user experience in certain cases...

http://www.phoronix.com/scan.php?page=news_item&px=Ubuntu-Stuttering-Touch-Screen

[gens]

just pin em all on one cpu core

[caligula]

Funny how Ubuntu Phone running native code & Qt performs worse than bytecode based Android phones. Somehow Java performs better than C++.

[andre30correia]

Funny how Ubuntu Phone running native code & Qt performs worse than bytecode based Android phones. Somehow Java performs better than C++.

java? what java?

[gens]

java? what java?

android is a java OS
to be fair there is lots of C, but its the java that makes it all slow and bloated

[Pajn]

Funny how Ubuntu Phone running native code & Qt performs worse than bytecode based Android phones. Somehow Java performs better than C++.

Java is JITed (and on Lollipop even AOT), the bytecode stopped beeing interprented in Android 2.2. QT also features GC so you have the same overhead there. And Ubuntu (as well as other systems based on QT 5) is using QML which is run under a JS enviroment featuring its own JIT and GC giving another layer of overhead (not as much as people usually think, but still noticeble).
To get a benifit of C++ here you have to get an OpenGL canvas and do all the graphics and memory management yourself, which is basically just for games.

(I know there are spelling errors but becouse vBullentin sucks and disables the browsers context menu with all corrections I can't be bothered to fix them)

[caligula]

Java is JITed (and on Lollipop even AOT), the bytecode stopped beeing interprented in Android 2.2. QT also features GC so you have the same overhead there. And Ubuntu (as well as other systems based on QT 5) is using QML which is run under a JS enviroment featuring its own JIT and GC giving another layer of overhead (not as much as people usually think, but still noticeble).
To get a benifit of C++ here you have to get an OpenGL canvas and do all the graphics and memory management yourself, which is basically just for games.

(I know there are spelling errors but becouse vBullentin sucks and disables the browsers context menu with all corrections I can't be bothered to fix them)

Ok, good to know. I thought the applications for low resource platforms (mobile) use native C++ for everything. IF QML is a JS environment, it seems to me that it could actually perform slower than AOT Java.

[boxie]

Also caligula JIT can actually be faster than compiled code (and in fact Java can be faster than C). When compiling C you only get one chance to choose what instructions to use, so you compile for the lowest common denominator in release code (e.g. amd64, i386), when using bytecode and JIT you can use all of the instructions a CPU has available to you and also react to the current state of the program better.

as for Android - if you see the "Android is upgrading" dialogue box after a software upgrade, that is the interpreter running and turning the android apps into compiled bytecode

[Luke_Wolf]

Java is JITed (and on Lollipop even AOT), the bytecode stopped beeing interprented in Android 2.2. QT also features GC so you have the same overhead there. And Ubuntu (as well as other systems based on QT 5) is using QML which is run under a JS enviroment featuring its own JIT and GC giving another layer of overhead (not as much as people usually think, but still noticeble).
To get a benifit of C++ here you have to get an OpenGL canvas and do all the graphics and memory management yourself, which is basically just for games.

(I know there are spelling errors but becouse vBullentin sucks and disables the browsers context menu with all corrections I can't be bothered to fix them)

Ehm... no. QML which is an interface description and scripting language has a GC, Qt does not. Qt uses an explicit Parent-Child hierarchy memory management scheme built into QObject, and you still have to explicitly delete.

[gens]

java is not even comparable to C++, let alone C

JiT, AoT, it doesn't matter as:
it has GC, and its bad (on a server, gigabytes of memory wasted)
java is a really high level language, thus hard to compile to anything even remotely performant
(compiling C++ on a real computer takes ages, you can not expect java to be JiT-ed in 2sec and work efficiently)

i know it's popular, but please don't ever compare it to even C++ let alone C