How to set device side queue size in pyopencl?

Question

In the Intel opencl 2.0 tutorial resource Sierpiński Carpet, they use the device side enqueue properties added in opencl 2.0. In the source code, there is a segment like this:

// You need to create device side queue for enqueue_kernel to work
// We set the device side queue to 16MB, since we are going to have a large 
// number of enqueues
cl_queue_properties qprop[] = {CL_QUEUE_SIZE, 16*1024*1024, 
      CL_QUEUE_PROPERTIES,                              
      (cl_command_queue_properties)CL_QUEUE_OUT_OF_ORDER_EXEC_MODE_ENABLE | 
      CL_QUEUE_ON_DEVICE | CL_QUEUE_ON_DEVICE_DEFAULT, 0};    
cl_command_queue my_device_q = 
      clCreateCommandQueueWithProperties(CLU_CONTEXT, 
            cluGetDevice(CL_DEVICE_TYPE_GPU), qprop, &status);

Now I want to use pyopencl to rewrite the code in python to learn dynamic parallelism method. But I can't find any instruction to set the queue size as the code shows. The CommandQueue API has the properties option, but in the document these options/values don't include size. Any suggestion?

glupescu glupescu · Accepted Answer · 2018-04-21T16:26:09

I am actually facing the exact same issue as you. Looking at the PyOpenCL backend only the function clCreateCommandQueue [1] is used but you actually need the clCreateCommandQueueWithProperties to be used.

As a quick change I tried, was to edit src/c_wrapper/command_queue.cpp and add code that creates the queue of the type described in Sierpinski carpet when PYOPENCL_CL_VERSION >= 0x2000.

It follows that the queue creation will be ok - or so it seems. But later on when I call the enqueue function I am getting INVALID_COMMAND_QUEUE. This error is both for AMD CL2.0 GPU as well as the INTEL 2.1 CPU EXPERIMENTAL. I am still debugging this.

[1] https://www.khronos.org/registry/OpenCL/sdk/1.0/docs/man/xhtml/clCreateCommandQueue.html [2] https://www.khronos.org/registry/OpenCL/sdk/2.0/docs/man/xhtml/clCreateCommandQueueWithProperties.html

How to set device side queue size in pyopencl?

1 Answers