Develop Reference

Very slow vkEndCommandBuffer on Android

I did some profiling and found out that vkEndCommandBuffer does a lot of work on Android (25% of render thread time in my application). The most strange thing to me is that it does huge memcpy (20% of render thread time).
I tried different flags in command buffer and command buffer pool, also I tried to reset command buffer implicitly and explicitly, but nothing helped. I found out that vkEndCommandBuffer works faster if I disable MSAA. But it doesn't make sense to me.
Stack:
qglinternal::vkEndCommandBuffer
QglCommandBuffer::End
A5xCommandBuffer::HwProcessWorkload
memcpy
Why is it so slow? And what is it doing? Any ideas?
UPD: I tested my app on 5 devices. App does 200-400 draw calls every frame:
Xiaomi MiA1. Android 7.1. Adreno 506. Driver version: 55.277.3829 (according Vulkan Caps Viewer). 30 fps. No memcpy in vkEndCommandBuffer, but it still takes 5% of render thread time.
Xiaomi MiA2 Lite. Android 9.0. Adreno 506. Driver version: 512.331.0. 20-25 fps. Huge memcpy, vkEndCommandBuffer takes 25.6% of render thread time.
Yandex YNDX-000SB. Android 8.1. Adreno 508. Driver version: 14.307.2170. 30 fps. Huge memcpy, vkEndCommandBuffer takes 22.7% of render thread time.
Google Pixel 2 XL. Android 10.0. Adreno 540. Driver version: 512.385.0. 60 fps (but it's expensive device). Huge memcpy, but vkEndCommandBuffer takes only 5.8% of render thread time.
Samsung Galaxy J7. Android 8.1. Mali-T830. 45-50 fps. vkEndCommandBuffer takes only 0.2% of render thread time.
Also I noticed next things:
all devices with Adreno do a lot of work in DrawIndexed. They are calling huge memset (wtf?);
all devices with Adreno don't reuse command buffers. They always free all resources of command buffer (even if I use implicit reset). It takes about 2-5% of render thread time depending on device.

how many the waves(threads) are scheduled and executed on the GPU using OpenCL?

I'm developing android app using OpenCL with Adreno GPU. I read the 'Snapdragon OpenCL General Programming and optimization'. but I can't see any information about size of wave(threads) or warp on Adreno devices.
On desktop GPU AMD have 64 threads wavefront size, and Nvidia GPU have 32. This information is very important for choosing best workgroup size, and making code optimization.
I wonder how many the waves are scheduled and executed on the GPU.
Can someone provide such information.

andengine (android opengl) low cpu usage

I have an andengine game, which has:
45-50-55 fps on a normal Galaxy S3, the phone temperature is warm.
stable 60 fps on CM11 Galaxy S3 with root in performance mode (maximum cpu frequence = 1400mhz) . With root you can modify the cpu frequence. The phone temperature is almost hot.
40-45fps on my Nexus 6 (without root), but this phone is faster than galaxy s3! The phone temperature is almost cold.
The resolutions of the game are the same!
The main question is: why does my game fps same on the both device? On Nexus6 it should be faster!
The game is: https://play.google.com/store/apps/details?id=com.hattedskull.gangsters

when a cpu is faster but does show less performance then the other cpus, it could be that it uses only 1 of 2,4,8,12 cores. thats just 25% usages, s the cpu stays cold. a single core cpu will always burn at 100%, and gets warm. Multithreading is the solution. that will "force" the cpu to go at 100%, and the game will run faster

I am answering my question, because it is not obvious (for me), so the solution is:
Performance mode: After rooting the phone, I changed the scaling governor (at processor) mode in performance, changing min hz was not necessary. Now the phone are hot, not warm!
Mobil ads bad performance: I switched off all the internet connections (wifi, mobile), therefore the mobile ad disappeared from the game. I use admob in my game, which has not the best performance.
These caused the FPS drops in my game(s)!

V4L2 FPS drops on android with more cores

I have three android devices Single core, Dual core and Quad core. I was able to make an app using v4l2 to grab the picture.
In standby mode all three devices are giving me 30FPS (as announced by camera hardware provider). But as soon as I start some processing on image and draw on canvas the FPS of Dual core and Quad core devices drops drastically. Single core device FPS reaches 28 which is acceptable but Dual core becomes 18 (on average) and Quad core 12.
I have used CPU performance governor in all three devices. Without performance mode FPS are even lower.
echo performance > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
Initially I thought it has something to do with customized linux kernel in android So,
I flashed PicUntu on quad core device but still I saw similar behavior in FPS drop. On Desktop with Windows and Ubuntu there is no such issue in the camera. I guess it has something to do with ARM.
Have anyone faced similar problem for UVC camera with V4L2 driver on android(ARM devices)? Is there any way to increase the FPS?
EDIT ** Adding some more information
For KitKat device if I bind my usb task to single core (taskset), FPS is improving by small factor. In kitkat overall performance is also better than Jelly bean.
I am not sure why usb speed suffers when the application goes to background even when overall cpu usage is small.

Android Canvas Performance Terrible on Droid

I've been developing a game for Android for the past few months, and it's just about finished. I recently acquired a Motorola Droid for testing purposes, as I developed the game using a HTC Incredible. On my Incredible I can get a pretty solid 59 fps throughout the game. On the Droid, the game becomes very choppy with an average of about 40 fps. Both phones are running Android 2.2.
I looked up the tech specs are here are the only differences I noted that might affect gameplay: 1 GHz processor vs 550 MHz and 512 MB RAM vs 256 MB RAM.
Just for giggles, I thought I would strip down the game to a very minimal state to see if it was my coding to blame. I stripped it down to the point where the only thing being down was drawing the main menu and moving various bitmaps around the screen. Not a hair over 45 fps.
So, is this the approximate cap for the Motorola Droid? If so...my game is pretty simple and non-CPU intensive, so what can I do? There are thousands of other Android games that are much more demanding than my own, yet they seem to run very smoothly.
Is it the fact that I'm using Android's built-in Canvas and not Open-GL or some other alternative? Would anybody recommend doing that?
Could somebody enlighten me to what might be my problem here?
Thanks in advance.

OpenGL ES is the way to go. Canvas is most likely implemented on top of OpenGL ES anyway, and not very efficiently by the sounds of it.

40fps is pretty good, the human eye can only detect jerkiness when the framerate falls below 25fps. Anything above 15fps is considered 'full motion'.
If you can see jitter then it may be the game pausing while the garbage collector kicks in - you can reduce this by reducing the number of objects that you create and you should be able to see it happening by using ddms.
Other than that perhaps there is a glitch calculating the frame rate?