OpenCL support for Mali-T628 MP6 on Arndale Octa?

Hi Chris,

We also want to use T628 for opencl computations on  Exynos5420, But our SOC has Android as OS. Can you please help us to find the opencl driver for android? OR we have to get the source and compile?

PS: If you feel my post will divert the original post's intention I can raise new post.

Thanks,

Veeranna

Hi Veeranna,

The driver is composed of 2 parts, kernel, and userspace binaries. The kernel space source code is open source and available from the link you posted, and that will need integrating into the kernel for your SoC, which is more than likely already done by your specific SoC/board/device vendor. What board/device are you using? If you're using a kernel other than the ones provided by the device/SoC/board vendor, then you will likely need to do this yourself.

Once that's done, you will need the matching userspace binary. We currently provide r3p0-02rel0 binaries for Linux (provided as part of the Chromebook guide), and an r4p0 release is coming very soon (currently stalled in legal review). We do not however currently offer any Android userspace binaries for any devices/boards, nor do we currently have any plans to, so these would need to come from your SoC/device/board vendor.

Hope this helps,

Chris

Thanks for the reply Chris,

We are using Exynos 5420 board from Insignal. Yes it has kernel level binary inside the device. Getting a driver at Android usespace will be very helpful, because we run our application on different vendor SOCs to compare the performance. The other SOCs we have has Android as the OS.

I will check in Insignal forums.

Thanks for your help.

Veeranna

Hi Chris,

I got the driver from Samsung/Insignal, and able to build the Andorid Image and Run. But we are observing random behavior in OpenCL APIs. Some time clcreateKernel fails and if re-run the app clcreateKernel returns success but clcreatebuffer fails with error code as zero and returned memory pointer as NULL. 

Can you give some to hint where to look.

Thanks,

Veeranna

Hi Veeranna,

Can you provide us with a simple reproducer? Also please let me know the driver version you're using, with adb pull /vendor/lib/egl/libGLES_mali.so && strings libGLES_mali.so | grep r[0-9]p[0-9] assuming it's in vendor and not system.

Thanks,

Chris

Hi Chris,

With above said command, I got version as 1.4 Midgard-"r3p0-01bet0. I will try to give simple app to run.

Thank you for help.

Veeranna

Interestingly simple median filter example runs fine(openCL on T628), but our application fails. Our application has many kernels and huge memory bandwidth will it be the reason?

Any suggestion for debugging will be helpful.

Thanks,

Veeranna

Hi veerannah,

I doubt simply having a lot of kernels would in itself be a problem, nor would I expect memory bandwidth to be an issue. Can you confirm whether you are creating all of your kernels up-front before any clEnqueueNDRange commands take place, or do you somewhat interleave kernel compilation and execution? Can you also confirm whether all program objects compile without error prior to the calls to clCreateKernel that consume them?

Thanks,

Chris

Hi Chris,

We create all our kernels first, then we allocate required buffers and then call clEnqueueNDRange. Sometime it fails to create some kernels(some are got created). And sometimes it fails in buffer allocation. It didnt hit clEnqueueNDRange yet.

Thanks,

Veeranna

It's interesting that its not deterministic where it fails. Without a reproducer I'm afraid I'm just guessing at possible causes. Also the driver itself is quite old now, we're currently at r4p0, so it is worth asking them when they plan to provide an up to date version as this could fix it.

Thanks,

Chris

I tried the SGEMM sample from the SDK:

root@arndale-octa:~/Mali_OpenCL_SDK_v1.1.0/samples/sgemm# ./sgemm

[PLUGIN INFO] Plugin initializing

[PLUGIN DEBUG]  './override.instr_config' not found, trying to open the process config file

[PLUGIN DEBUG]  './sgemm.instr_config' not found, trying to open the default config file

[PLUGIN ERROR] Couldn't open default config file './default.instr_config'.

[PLUGIN INFO] No configuration file found, attempting to use environment

[PLUGIN INFO] CINSTR GENERAL: Output directory set to: .

[PLUGIN INFO] No instrumentation features requested.

^C[  384.380000] Mali<ERROR, BASE_MMU>: kbase_mmu_report_fault_and_kill Unhandled Page fault in AS0 at VA 0x00000000B6F0E100

[  384.380000] raw fault status 0x820003C3

[  384.380000] decoded fault status: SLAVE FAULT

[  384.380000] exception type 0xC3: TRANSLATION_FAULT

[  384.380000] access type 0x3: WRITE

[  384.380000] source id 0x8200

[  384.400000] Mali<ERROR, BASE_JM>: kbase_job_done_slot t6xx: GPU fault 0x43 from job slot 1

The program hangs after the [PLUGIN INFO] messages are printed. When I press ctrl+c, the kernel messages appear, indicating that the GPU run into trouble?

That looks like an integration problem to me, it's worth reporting to Linaro, as I believe that's the kernel you're using?

Hope this helps,

Chris

Hi Chris,

Finally we are able to run our application on T628. But performance numbers are not good. Do we get any improvement if we move r4p0 driver?

Any other suggestions to improve the GPU performance will be helpful.

Thanks,

Veeranna