Run OpenCL sample in Android

Thks Chris for ur reply

But i just saw ur post in another discussion "

Is Mali OpenCL SDK will support Android? Nov 28,2013 10.21 AM . U had told the OpenCL samples will run for Ubuntu but not for Android.

Is the Mali SDK updated after that since it has been 2 yrs?

I am not critical of ur above answer but i just want to understand it:)

Thks

Thks Chris for ur reply

But i just saw ur post in another discussion "

Is Mali OpenCL SDK will support Android? Nov 28,2013 10.21 AM . U had told the OpenCL samples will run for Ubuntu but not for Android.

Is the Mali SDK updated after that since it has been 2 yrs?

I am not critical of ur above answer but i just want to understand it:)

Thks

Hi aravind,

It was over a year ago so I don't remember specifically but it is certainly true that the opencl SDK examples do not compile for, or run on android out of the box. They require some mods to do so, as described above, and probably I had not attempted it myself at the time so couldn't say with any confidence whether it was or wasn't possible. I have since done it though so am happier to say it is possible although it is of course not strictly supported or guaranteed, i have had success in the past. The Android/Application.mk files are quite trivial to derive from ndk samples so I would encourage you to give it a go and let us know if you have any problems that we could help with.

Hth,

Chris

Thks Chris for ur help.

I will try it nd come back to u:)

Thks once again

Hello Chris

I hv got Mali SDK.

It contains the samples.i choose "hello_world_opencl". The file contents are hello_world_opencl->assets,hello_world_opencl.cpp,Makefile.

Inside assets->hello_world_opencl.cl

Basically i will hv to write the Android.mk and Application.mk files and also the source java file right?

Can u just elaborate on this?

Thanks

Hi Aravind,

Sorry for late reply, was at GDC last week. You will need to write the Android.mk and Application.mk files, but you won't need to write any Java files, you can just build an executable, i.e. not an APK, just a raw binary, with the NDK. It's fairly trivial to write the Android.mk file. Take a very simple NDK sample app and copy the jni folder, then modify that to include the correct files and build a binary, you should have no trouble! I'll try and get an example to you this week.

Thanks,

Chris

Thks Chris for reply.

1) I saw NDK samples. But the thing is the Android.mk file varies a lot with the application. So just replacing the <file name> will help?

2)Also the activity file will load the .so ( got from the cpp file) and as a result we can run the application. Without that wont we just get a default "hello world" message?

3) Say i want to run the "mandelbrot" sample in Mali SDK as an android app. What changes should i do?

Thks

Aravind

Thks Chris

Ur knowledge base is very extensive.

So 1 prblem is solved. The changes in Android.mk still remains though. It will be nyc if u could provide furhter insights into it

Thanks

Aravind

Hi Aravind,

So I've given it a go at producing the Android NDK makefiles necessary to build the OpenCL samples... I've attached a zip which you should be able to unzip over the top of your OpenCL SDK. It will add a couple of jni folders, one in lib and one in samples\hello_world_opencl. To build the hello_world_opencl sample fire up a command prompt and do the following:

1. cd to Mali_OpenCL_SDK_v1.1.0\lib
2. run ndk-build
3. cd to Mali_OpenCL_SDK_v1.1.0\samples\hello_world_opencl
4. run ndk-build

The first ndk-build will build the OpenCL stub library, which exists purely to satisfy the link requirements for the samples. It is not a real implementation of OpenCL, and indeed at runtime you will be running against the real implementation present on the device. The second ndk-build will build the sample.

Note that this is only enough to make it build, I have made no modifications to the source code itself to make it run correctly, i.e. looking for files in the right place, etc, but this should be enough to get you building and running at least. I'd recommend building clinfo and checking that you get the correct diagnostic output.

Hth,

Chris

Thanks a lot Chris.

I tried ndk-build for OpenCL stub.

ara@Aravind:~/Downloads/Mali_OpenCL_SDK_v1.1.0/lib$ ndk-build

make: *** No rule to make target `jni\../..\lib\opencl_stubs.c', needed by `obj/local/armeabi-v7a/objs/OpenCL/..\lib\opencl_stubs.o'.  Stop.

It is not finding the opencl_stub file. I changed the Android.mk from LOCAL_SRC_FILES := opencl_stubs.c        to     LOCAL_SRC_FILES := ..\lib\opencl_stubs.c

But no use. can u plse help?

Thanks

Hi Aravind,

My bad, Linux doesn't like the backslashes (I wrote this on Windows ) change the backslashes to forward slashes in the Android.mk files and you're good to go

Cheers,

Chris

Hello Chris

Thanks a lot.It worked.

A libs folder and and obj folder is created inside <hello_world_sample> and inside <Mali_SDK--- / lib >

How should I run it?

Also the procedure is the same for all samples right , except we have to change the source file ?

Thanks a lot

Aravind

Hi Aravind,

Yeah the process is the same, just look at the makefiles to see what files are compiled and what the includes are for specific samples and recreate the Android.mk files I provided for those samples to run them, just copy the binary to the device, chmod it so it's executable and run it from the shell. It will fall over trying to load a file most likely, so you will need to modify the source so it looks in /sdcard/ or something. From memory at present it will look for an Assets folder in the current working dir.

Hth,

Chris

Thks Chris

So i will have to copy the hello_world_opencl executable present inside obj->local->armeabi-v7a to device.

i run $ adb shell pm setInstallLocation 2 to install it in sdcard.

To modify source, u mean i will hv to change the Android.mk file LOCAL_SRC_FILES := hello_world_opencl.cpp  to look inside sdcard? Sorry i dont understand

Thanks

Aravind

Hi Aravind,

setInstallLocation is a package manager command, and will only affect where the package manager installs packages. In this case you don't have a package to install, I assume you'll probably just push the thing with adb push somewhere like /sdcard/ and run it from there?

As for source, I am referring to the actual C++ source code, not the Android.mk file. Generally speaking there may be some minor issues running on Android which you may need to fix, e.g. broken file paths, but then again it might just work without issues. We don't routinely test on Android as we don't support it out of the box.

Hth,

Chris