OSX 10.8, GT650M, OpenCL Hello World example fails; Can't create command queue

Question

Level 1

0 points

OSX 10.8, GT650M, OpenCL Hello World example fails; Can't create command queue

The official `Open Cl Hello World` example http://developer.apple.com/library/mac/#samplecode/OpenCL_Hello_World_Example/In troduction/Intro.html

fails with "Can't create command queue" err: -30, CL_INVALID_VALUE, as does the examples from the OpenCL books http://code.google.com/p/opencl-book-samples/ .

I'm on a fresh install of XCode 4.4.1, OS X 10.8.1 and don't know how to proced. I crossposted this issue to the MacRumors Forum, where other users stated that the code works. I'm beginning to think that I have a faulty machine/driver/installation but want to do everything in my power to get this to work (I need this for my master thesis)

MacBook Pro with Retina display, OS X Mountain Lion (10.8.1), XCode 4.4.1

Posted on Aug 29, 2012 2:29 PM

Reply

Answer 1

xnav

Level 5

7,089 points

Aug 29, 2012 4:38 PM in response to oschrenk

Do you have the correct graphics chipset?

To use the GPU as a compute device, use one of the following devices:

- MacBook Pro w/NVidia GeForce 8600M

- Mac Pro w/NVidia GeForce 8800GT

Reply

Answer 2

xnav

Level 5

7,089 points

Aug 29, 2012 5:34 PM in response to oschrenk

Seems you might be OK, did you see this thread?

Reply

Answer 3

Michel_L

Level 1

0 points

Jan 3, 2013 12:14 PM in response to oschrenk

Did you ever find a solution to this issue?

I have started investigating the use of OpenCL for use in a graphics app. However I have found two nagging issues:

1) Performance is not consistent: One run may give a performance result and the next one half that performance. It seems this may be due to running other applications that may tie some GPU resources, even if they are not displayed.

2) Similar issue to the one described by oschrenk but... I can run my tests a few times but then suddenly, all further tests will return a CL_INVALID_VALUE when trying to instantiate a command queue and I can never run again. The only fix I find is to reboot my laptop. Clearly not an acceptable solution.

This is a show stopper. Anybody knows what may be done about it?

Reply

Answer 4

Feb 26, 2013 3:14 AM in response to Michel_L

Regarding the problem

Can't create command queue" err: -30, CL_INVALID_VALUE

I also observe this on my MBP. It is a driver issue, reboot and you can create 20-30 command queues until it fails again...

I submitted a bug report to Apple a while ago, please do the same if you did not yet do so.

Reply

Answer 5

oschrenk Author

Level 1

0 points

Feb 26, 2013 3:36 AM in response to Philippe Robert

> I also observe this on my MBP. It is a driver issue, reboot and you can create 20-30 command queues until it fails again...

This is what I did in the end when the problem did occur. I filed a bug report back in the days but could never reproduce it consistently.

Reply

Answer 6

Oct 31, 2013 3:47 AM in response to oschrenk

Hi, I just wanted to let everyone know that I believe this issue has now been resolved with OSX Mavericks. I submitted a bug report (# 15159324) on 5th October 2013 and received a report last night.

To fix for yourself:

Download and install OSX Mavericks from http://itunes.apple.com/us/app/os-x-mavericks/id675248567?mt=12
Download the official Hello World example - http://developer.apple.com/library/mac/#samplecode/OpenCL_Hello_World_Example/In troduction/Intro.html
CMD-R to build and run on the CPU - you should get
Computed '1024/1024' correct values!
Change line 116 in 'hello.c' to read : int gpu = 1;
CMD-R to build and run on the GPU - you should get
Computed '1024/1024' correct values!

If you do then all should now be ok to use the GT650m

Reply

Answer 7

oschrenk Author

Level 1

0 points

Oct 31, 2013 5:33 AM in response to Indigo.Jones

Great! Now I need an excuse to get back into the GPU programming world to try it out. Do you know if the internal graphics chip can now be used as well?

Reply

Answer 8

Oct 31, 2013 5:36 AM in response to oschrenk

Yes the Intel HD Graphics 4000 can also be accesed but it looks like it might not support math functions (I don't know much about this card).

Reply