Name String

    cl_intel_simultaneous_sharing

Contributors

    Krzysztof Laskowski, Intel
    Bartosz Sochacki, Intel
    Eric L Palmer, Intel
    Ben Ashbaugh, Intel
    Adam T Lake, Intel

Contact

    Krzysztof Laskowski, Intel (krzysztof.laskowski 'at' intel.com)

Version

    Version 7, October 14, 2014

Number

    OpenCL Extension #34

Status

    Complete

Extension Type

    OpenCL platform extension

Dependencies

    OpenCL 1.2. This extension is written against revision 19 of the 
    OpenCL 1.2 Specification and revision 19 of the OpenCL 1.2 Extension 
    Specification.

Overview

    Currently OpenCL 1.2 Extension Spec forbids to specify interoperability 
    with multiple graphics APIs at clCreateContext or clCreateContextFromType 
    time and defines that CL_INVALID_OPERATION should be returned in such
    cases as noted e.g. in chapters dedicated to sharing memory objects with 
    Direct3D 10 and Direct3D 11.

    The goal of this extension is to relax the restrictions and allow to
    specify simultaneously these combinations of interoperabilities that are
    supported by a given OpenCL device.

New Tokens

    Accepted as a property being queried in the <param_name> parameter
    of clGetDeviceInfo:
    
        CL_DEVICE_SIMULTANEOUS_INTEROPS_INTEL        0x4104
        CL_DEVICE_NUM_SIMULTANEOUS_INTEROPS_INTEL    0x4105

Additions to chapter 4 of the OpenCL 1.2 Specification

    4.2 Querying Devices

    Extend table 4.3 to include the following entry:

    --------------------------------------------------------------------------
    cl_device_info             Return Type  Description
    --------------             -----------  -----------
    CL_DEVICE_NUM_SIMULTANEOUS cl_uint      Number of supported combinations 
    _INTEROPS_INTEL                         of graphics API interoperabilities 
                                            that can be enabled simultaneously 
                                            within the same context.

                                            The minimum value is 1.
                                            
    CL_DEVICE_SIMULTANEOUS     cl_uint[]    List of <n> combinations of context
    _INTEROPS_INTEL                         property names describing graphic APIs
                                            that the device can interoperate with
                                            simultaneously by specifying the
                                            combination in the <properties>
                                            parameter of clCreateContext and
                                            clCreateContextFromType.

                                            Each combination is a set of 2
                                            or more property names and is
                                            terminated with zero. 

                                            <n> is the value returned by the 
                                            query for 
                                            CL_DEVICE_NUM_SIMULTANEOUS_INTEROPS_INTEL. 
    --------------------------------------------------------------------------
        
    4.4 Contexts
   
    Add to the list of errors for clCreateContext:

    "CL_INVALID_OPERATION if a combination of interoperabilities with multiple graphics 
    APIs is specified which is not on the list of valid combinations returned by 
    the query for CL_DEVICE_SIMULTANEOUS_INTEROPS_INTEL."

    Add to the list of errors for clCreateContextFromType the same new errors 
    described above for clCreateContext.

Additions to section 9.6.4 of the OpenCL 1.2 Extension Specification

    Replace the section about CL_CONTEXT_INTEROP_USER_SYNC property support with:

    "OpenCL / OpenGL sharing does not support the CL_CONTEXT_INTEROP_USER_SYNC property 
    defined in table 4.5. Specifying this property when creating a context with OpenCL /
    OpenGL sharing will return an appropriate error or be ignored for OpenGL sharing if
    sharing with another graphics API supporting the CL_CONTEXT_INTEROP_USER_SYNC 
    property is also specified."

    Replace the description of CL_INVALID_PROPERTY error code with:

    "errcode_ret returns CL_INVALID_PROPERTY if an attribute name other than those 
    specified in table 4.5 or if CL_CONTEXT_INTEROP_USER_SYNC is specified in properties
    and there is no graphics API interoperability specified that supports it."

Additions to section 9.9.5 of the OpenCL 1.2 Extension Specification

    Remove the following description of CL_INVALID_PROPERTY error code:

    "CL_INVALID_OPERATION if Direct3D 10 interoperability is specified by setting 
    CL_INVALID_D3D10_DEVICE_KHR to a non-NULL value, and interoperability with another 
    graphics API is also specified."

Additions to section 9.11.5 of the OpenCL 1.2 Extension Specification

    Remove the following description of CL_INVALID_PROPERTY error code:

    "CL_INVALID_OPERATION if Direct3D 11 interoperability is specified by setting 
    CL_INVALID_D3D11_DEVICE_KHR to a non-NULL value, and interoperability with another 
    graphics API is also specified."

Additions to cl_intel_dx9_media_sharing extension specification:

    Remove the following description of CL_INVALID_PROPERTY error code:

    "CL_INVALID_OPERATION if DirectX 9 interoperability is specified by setting   
    CL_CONTEXT_D3D9_DEVICE_INTEL, CL_CONTEXT_D3D9EX_DEVICE_INTEL, or
    CL_CONTEXT_DXVA_DEVICE_INTEL to a non-NULL value, and interoperability with any 
    other graphics API is also specified."

Example Usage

    cl_uint  SimInteropsNum;
    cl_uint* SimInterops;
    size_t   SimInteropsSize;
    
    clGetDeviceInfo( deviceID, 
                     CL_DEVICE_NUM_SIMULTANEOUS_INTEROPS_INTEL, 
                     sizeof( SimInteropsNum ), 
                     &SimInteropsNum, 
                     NULL );
    clGetDeviceInfo( deviceID, 
                     CL_DEVICE_SIMULTANEOUS_INTEROPS_INTEL, 
                     0, 
                     NULL, 
                     &SimInteropsSize );
    SimInterops = new cl_uint[ SimInteropsSize / sizeof( cl_uint ) ];
    clGetDeviceInfo( deviceID, 
                     CL_DEVICE_SIMULTANEOUS_INTEROPS_INTEL, 
                     SimInteropsSize, 
                     SimInterops, 
                     NULL );
    
    bool SimInteropsCheck[] = { false, false, false };
    bool GLD3D11SimInteropSupported = false;
    cl_uint property = 0;
    
    for( int i = 0; i < SimInteropsNum; i++ )
    {
        SimInteropsCheck[0] = false;
        SimInteropsCheck[1] = false;
        SimInteropsCheck[2] = false;
        do
        {
            property = *SimInterops++;
            if( property == CL_GL_CONTEXT_KHR )
                SimInteropsCheck[0] = true;
            if( property == CL_WGL_HDC_KHR )
                SimInteropsCheck[1] = true;
            if( property == CL_CONTEXT_D3D11_DEVICE_KHR )
                SimInteropsCheck[2] = true;
        }
        while( property != 0 );
            
        if( SimInteropsCheck[0] && SimInteropsCheck[1] && SimInteropsCheck[2] )
        {
            GLD3D11SimInteropSupported = true;
            printf("This device supports GL and D3D11 simultaneous sharing.\n");
            break;
        }
    }
    if( !GLD3D11SimInteropSupported )
    {
        printf("This device doesn't support GL and D3D11 simultaneous sharing.\n");
    }

Issues

    - It might be good to enumerate changes to all chapters talking about sharing 
      with each graphics API. However this is troublesome because the restriction 
      for the interops being mutually exclusive is not consistent throughout specs. 
      The restriction exists in chapters about sharing with Direct3D 10, Direct3D 11 
      and DX9 Media Intel vendor extension but is not explicitly stated in chapters 
      about sharing with OpenGL and DX9 Media KHR extension. 

      RESOLVED: Added description of all changes explicitly.

Revision History

    Version 1, 2014/07/28 (Krzysztof Laskowski) - Initial version.
    Version 2, 2014/07/29 (Krzysztof Laskowski) - Changed minimum value of
                                                  CL_DEVICE_NUM_SIMULTANEOUS_INTEROPS_INTEL
                                                  to 1.
                                                  Added section about usage of
                                                  CL_CONTEXT_INTEROP_USER_SYNC.
    Version 3, 2014/09/29 (Krzysztof Laskowski) - Added numerical values for the new tokens.
    Version 4, 2014/10/02 (Krzysztof Laskowski) - Rephrased the description of CL_DEVICE
                                                  _SIMULTANEOUS_INTEROPS_INTEL.
    Version 5, 2014/10/06 (Krzysztof Laskowski) - Added description of changes
                                                  to OpenGL, D3D10, D3D11 and Intel DX9 
                                                  Media sharing specifications.
                                                  Removed redundant paragraphs from 
                                                  the description of CL_DEVICE_SIMULTANEOUS_
                                                  INTEROPS_INTEL.
    Version 6, 2014/10/09 (Krzysztof Laskowski) - Added Example Usage section.
    Version 7, 2014/10/14 (Krzysztof Laskowski) - Moved Issues section to the bottom.
                                                  Marked as complete.