What really causes android lag?

[anon(5780458)]

I see videos on YouTube all the time with people messing around with a device saying "it's very smooth, no lag" as I see the jittery animation and prevalent lag.

This. It's hilarious how YouTube reviewers say "buttery smooth", "no lag whatsoever" etc. and while they're speaking those words the phone is visibly stuttering with massive touchscreen input latency.

The only phone I've seen so far that doesnt's stutter on the home screen is the Nexus 4. It's as if they've custom developed the whole thing in OpenGL just to prevent the lag instead of using the Android SDK control widgets. But even on the Nexus 4 every normal app that developers make has massive stuttering ang input lag.

This guy's observations are on the dot:
Nexus 4 First Impressions

 

[anon(5780458)]

What problem?
The flip side of this is that iOS has to have loading and splash screens for even small apps because the background processes are reniced and are not yet finished when the UI is waiting for them. For many folks, that is more annoying than a few milliseconds of stutter between visually starting a process and seeing it launch. That spinner on iOS is there for a reason, and developers are required to use it (or another function of their choosing) to show something to the user while waiting for the processes to start in the background while the UI takes all the CPU time.

There is nothing (short of using a co-processor to run the UI at a higher priority while focusing the full SoC on the actual processes being launched) that can fix this. You're going to have to wait for the things you tap to start working one way or the other. Anyone with general knowledge of multi-threaded software development can tell you this.

Wrong. You're thinking of Windows, Linux and Android apps where it's completely up to the developer to make a non-laggy UI that doesn't freeze when tapping something.

iOS and Mac OS X don't work like this. Their CoreAnimation system will continue to render fluid animations even if you're hogging the CPU in a button click event in a single threaded app. It doesn't need a second processor core. Even on single core devices the system will ensure the CoreAnimation thread gets all the CPU time it needs and only then processes your (badly written) CPU hogging event. Badly written apps that use animations run smoothly on iOS.

The primary issue however is low developer morale. Androd in general is a **** platform to develop for. There are major problems like a simple ListView not working on many devices because the image in your custom cell layout triggered some bug in a vendor's customised image decompression routine.

Google themselves don't care that their own apps run like *** on Android but are vastly superior on iOS (every single one: YouTube, Maps, Google+, Crome (can't compare the rendering engine but the tabs and UI lag on Android)).

 

[Dreamliner330]

I switched from a RAZR MAXX HD to an iPhone 5 on Verizon because I've never had an iPhone and wanted to try one. Except for the lack of simultaneous Voice/LTE, the iPhone had been excellent.

I Jailbroke it immediately and have my calendar on the lockscreen, quick settings and system wide ad-bock. I also sped up the transition animations.

I've always been picky on the details, hated lag/stutter and am a display snob. The screen and Fluidity was so much better on the iPhone 5 over the RAZR MAXX HD, so much.

I bought a GS4 when it released, and it stuttered so bad I sent it back like a hot potato. I'm typing on a GS4 now with the newest Software Update that addressed the stutters, it's better, but still not as smooth as even the HTC One.

I'm at a bit of a crossroads, I've heavily considered the HTC One and flashing it with a Google Edition ROM, but I know it won't be as smooth as the iPhone....

...The app quality is just so much better on the iPhone, heck it even loads YouTube videos faster...with less ads!

 

[AlexanderE]

.
Some people just don't notice.

That's exactly it. It's the same with all the new LED backlights on cars. In order to make them cheaper, car manufacturers use slow PWM in order to adjust their brightness -- so slow indeed that I'm constantly distracted by all the blinking around me. If I tell people that, they think I'm from Mars to even notice that.

 

[tippmann15]

Certain phones will lag a LOT and some not at all, as example the note 2 is smooth as butter. The iPhone will have problems too, at least mine does ...I just can't take the iPhone 5's constant need to recharge.

GS4/iPhone5

 

[anon(5780458)]

the note 2 is smooth as butter.

This is the most ridiculous thing I've ever heard. The Note 2 has 300ms input lag once you start using it daily.

 

[rmzalbar]

I think people are confused about lag caused by the phone being busy (overhead, pipelining, thread blocking, i/o contention or whatever) which is variable in nature and comes and goes, i.e., if the phone is busy and you get a delay or stuttering when scrolling, launching an app, or tapping a button, vs the small but constant delay between the time you touch the screen and the time the phone visibly registers that response.

I think what the OP is complaining about is the small constant delay that is always present even if the phone is doing nothing. This doesn't affect the "smoothness" of the phone or responsiveness of launching or using apps. The average user would never notice this unless they were a gamer trying to play a timing-critical reflex game.

I've found that twitch-action games that are unplayable due to touch latency respond perfectly to alternate input devices such as gamepads, apparently placing this problem somewhere in the touch input system. I don't know if this varies from phone to phone (hardware or hardware-specific driver) or if the delay is in the OS.

 

[anon(5780458)]

Android devices have both. Every one of them regardless of cost has 150ms input lag at minimum and the vast majority of them stutter and lag in every single app. Devices like the Nexus 4 have less stutter but very high input lag. The input lag is visually more prominent when the device is smoother because it's clearly visible that the UI is dragging behind your finger while scrolling.

 

[calderwa]

Hi.
My observations while creating an openGL live wallpaper.
The one huge issue which showed up was the frame rate stuttering very badly in the face of heavy user input events - dragging your finger around on the screen really hits it hard on Nexus 7 (old). In contrast, Nexus 4 works great and appears unaffected by the user input. An interesting fact is that the wallpaper seems impervious to input event effects when it is running in the Live Wallpaper Launcher. This led me to believe there would be a fix I could apply, but everything i have looked at has the wrong access level to allow me to tinker. Which is a BIG shame. The wallpaper goes from "pretty cool" on Nexus 4 to ranging between "pretty cool" and "what beginner wrote this stuff?" depending on what the user does to the screen on Nexus 7.
Android is a badly flawed architecture. Google are interested only in putting in new selling point features rather than actually making it good. I have reported and seconded bugs which are quite bad and yet have remained unfixed (in some cases even unacknowledged) for years. I have written software for 30 years now and Android has been the most frustrating, dispiriting system I have encountered in all that time. So, Google engineers are "geniuses"? Pah! Maybe they should have gotten in some really experienced guys at the start.