7 Replies Latest reply on Dec 7, 2017 1:28 AM by dipak

    OpenCL CL_DEVICE_SIMD_PER_COMPUTE_UNIT_AMD returns 0 in amdgpu-pro 17.70

    FangQ

      my opencl code needs to use the stream processor number to estimate a default workgroup/workitem configurations. Using CL_DEVICE_MAX_COMPUTE_UNITS and CL_DEVICE_SIMD_PER_COMPUTE_UNIT_AMD, I was able to estimate the core counts in AMD GPUs, but I found the CL_DEVICE_SIMD_PER_COMPUTE_UNIT_AMD call returns 0 in the latest Linux driver (amdgpu-pro 17.70), here is the code

       

      mcxcl/mcx_host.cpp at master · fangq/mcxcl · GitHub

       

      I am wondering if this is expected behavior. If CL_DEVICE_SIMD_PER_COMPUTE_UNIT_AMD is no longer valid, what other approach I can use to estimate core numbers?

        • Re: OpenCL CL_DEVICE_SIMD_PER_COMPUTE_UNIT_AMD returns 0 in amdgpu-pro 17.70
          dipak

          Hi,

          Thanks for reporting this. AFAIK, OCL run-time should support this query as long as cl_amd_device_attribute_query is reported. If the extension was reported, but the value was still 0, then there might be a problem with the driver. Please share the clinfo output and setup details.

          Btw, did you observe the problem with earlier versions of amdgpu-pro or just for this version only?

           

          Regards,

            • Re: OpenCL CL_DEVICE_SIMD_PER_COMPUTE_UNIT_AMD returns 0 in amdgpu-pro 17.70
              FangQ

              I did not have this issue with amdgpu-pro 16.30 on another Ubuntu 14.04 box, which has a R9 nano and RX 480.

               

              A correction, the problematic amdgpu-pro driver is 17.40, the OS is Ubuntu 16.04. I uninstalled the amdgpu-pro driver yesterday and installed rocm 1.6 (which has a module rocm-amdgpu-pro with version 17.40-492261), I can see the same problem where CL_DEVICE_SIMD_PER_COMPUTE_UNIT_AMD returns 0.

               

              the clinfo output is attached below:

               

              fangq@pangu:$ clinfo

              Number of platforms                               1

                Platform Name                                   AMD Accelerated Parallel Processing

                Platform Vendor                                 Advanced Micro Devices, Inc.

                Platform Version                                OpenCL 2.0 AMD-APP (2508.0)

                Platform Profile                                FULL_PROFILE

                Platform Extensions                             cl_khr_icd cl_amd_event_callback

                Platform Extensions function suffix             AMD

               

               

                Platform Name                                   AMD Accelerated Parallel Processing

              Number of devices                                 1

                Device Name                                     gfx900

                Device Vendor                                   Advanced Micro Devices, Inc.

                Device Vendor ID                                0x1002

                Device Version                                  OpenCL 1.2

                Driver Version                                  1.1 (HSA,LC)

                Device OpenCL C Version                         OpenCL C 2.0

                Device Type                                     GPU

                Device Profile                                  FULL_PROFILE

                Max compute units                               64

                Max clock frequency                             1630MHz

                Device Partition                                (core)

                  Max number of sub-devices                     64

                  Supported partition types                     none specified

                Max work item dimensions                        3

                Max work item sizes                             1024x1024x1024

                Max work group size                             256

                Preferred work group size multiple              64

                Preferred / native vector sizes               

                  char                                                 4 / 4     

                  short                                                2 / 2     

                  int                                                  1 / 1     

                  long                                                 1 / 1     

                  half                                                 1 / 1        (cl_khr_fp16)

                  float                                                1 / 1     

                  double                                               1 / 1        (cl_khr_fp64)

                Half-precision Floating-point support           (cl_khr_fp16)

                  Denormals                                     No

                  Infinity and NANs                             No

                  Round to nearest                              No

                  Round to zero                                 No

                  Round to infinity                             No

                  IEEE754-2008 fused multiply-add               No

                  Support is emulated in software               No

                  Correctly-rounded divide and sqrt operations  No

                Single-precision Floating-point support         (core)

                  Denormals                                     Yes

                  Infinity and NANs                             Yes

                  Round to nearest                              Yes

                  Round to zero                                 Yes

                  Round to infinity                             Yes

                  IEEE754-2008 fused multiply-add               Yes

                  Support is emulated in software               No

                  Correctly-rounded divide and sqrt operations  Yes

                Double-precision Floating-point support         (cl_khr_fp64)

                  Denormals                                     Yes

                  Infinity and NANs                             Yes

                  Round to nearest                              Yes

                  Round to zero                                 Yes

                  Round to infinity                             Yes

                  IEEE754-2008 fused multiply-add               Yes

                  Support is emulated in software               No

                  Correctly-rounded divide and sqrt operations  No

                Address bits                                    64, Little-Endian

                Global memory size                              8573157376 (7.984GiB)

                Error Correction support                        No

                Max memory allocation                           7287183769 (6.787GiB)

                Unified memory for Host and Device              No

                Minimum alignment for any data type             128 bytes

                Alignment of base address                       1024 bits (128 bytes)

                Global Memory cache type                        Read/Write

                Global Memory cache size                        16384

                Global Memory cache line                        64 bytes

                Image support                                   Yes

                  Max number of samplers per kernel             26751

                  Max size for 1D images from buffer            65536 pixels

                  Max 1D or 2D image array size                 2048 images

                  Max 2D image size                             16384x16384 pixels

                  Max 3D image size                             2048x2048x2048 pixels

                  Max number of read image args                 128

                  Max number of write image args                8

                Local memory type                               Local

                Local memory size                               65536 (64KiB)

                Max constant buffer size                        7287183769 (6.787GiB)

                Max number of constant args                     8

                Max size of kernel argument                     1024

                Queue properties                              

                  Out-of-order execution                        No

                  Profiling                                     Yes

                Prefer user sync for interop                    Yes

                Profiling timer resolution                      1ns

                Execution capabilities                        

                  Run OpenCL kernels                            Yes

                  Run native kernels                            No

                printf() buffer size                            4194304 (4MiB)

                Built-in kernels                              

                Device Available                                Yes

                Compiler Available                              Yes

                Linker Available                                Yes

                Device Extensions                               cl_khr_fp64 cl_khr_global_int32_base_atomics cl_khr_global_int32_extended_atomics cl_khr_local_int32_base_atomics cl_khr_local_int32_extended_atomics cl_khr_int64_base_atomics cl_khr_int64_extended_atomics cl_khr_3d_image_writes cl_khr_byte_addressable_store cl_khr_fp16 cl_khr_gl_sharing cl_amd_media_ops cl_amd_media_ops2 cl_khr_subgroups cl_khr_depth_images cl_amd_liquid_flash cl_amd_copy_buffer_p2p

               

               

              NULL platform behavior

                clGetPlatformInfo(NULL, CL_PLATFORM_NAME, ...)  AMD Accelerated Parallel Processing

                clGetDeviceIDs(NULL, CL_DEVICE_TYPE_ALL, ...)   Success [AMD]

                clCreateContext(NULL, ...) [default]            Success [AMD]

                clCreateContextFromType(NULL, CL_DEVICE_TYPE_CPU)  No devices found in platform

                clCreateContextFromType(NULL, CL_DEVICE_TYPE_GPU)  Success (1)

                  Platform Name                                 AMD Accelerated Parallel Processing

                  Device Name                                   gfx900

                clCreateContextFromType(NULL, CL_DEVICE_TYPE_ACCELERATOR)  No devices found in platform

                clCreateContextFromType(NULL, CL_DEVICE_TYPE_CUSTOM)  No devices found in platform

                clCreateContextFromType(NULL, CL_DEVICE_TYPE_ALL)  Success (1)

                  Platform Name                                 AMD Accelerated Parallel Processing

                  Device Name                                   gfx900

               

               

              ICD loader properties

                ICD loader Name                                 OpenCL ICD Loader

                ICD loader Vendor                               OCL Icd free software

                ICD loader Version                              2.2.8

                ICD loader Profile                              OpenCL 1.2

              NOTE: your OpenCL library declares to support OpenCL 1.2,

              but it seems to support up to OpenCL 2.1 too.