Name String

    cl_codeplay_set_threads

Contributors

    Erik Tomusk, Codeplay Software Ltd.

Contact

    Erik Tomusk, Codeplay Software Ltd. (erik 'at' codeplay.com)

Version

    Version 1, November 14, 2018

Number

    OpenCL Extension #XX

Status

    Proposal

Dependencies

    OpenCL 1.2 is required.

Overview

    This extension allows user code to set the maximum number of threads that a
    CPU device will use. The CPU device may use fewer threads.

New Types

    None

New API Functions

    cl_int CL_API_CALL clSetNumThreadsCODEPLAY_fn(cl_device_id device,
                                                  cl_uint max_threads);

Add a new Section 5.XX - "Device Configuration":

    Some devices can be configured on initialization.

Add a new section 5.xx.1 - "Limiting Number of CPU Threads"

    On devices of type CL_DEVICE_TYPE_CPU, the function

        cl_int CL_API_CALL clSetNumThreadsCODEPLAY_fn(cl_device_id device,
                                                      cl_uint max_threads);

    is used to set the maximum number of worker threads. The CPU device may use
    fewer threads.

    <device> must be a valid cl_device_id.

    <max_threads> must greater than 0.

    clSetNumThreadsCODEPLAY_fn returns CL_SUCCESS on successful execution. On
    failure, it will return one of the following error codes:

    * CL_INVALID_DEVICE_TYPE if <device> does not support
      cl_codeplay_set_threads.
    * CL_INVALID_VALUE if <max_threads> is 0.
    * CL_DEVICE_NOT_AVAILABLE if it is not possible to set the maximum number
      of threads.

Revision History

    Version 1 (2018/11/14): Initial proposal.