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OpenCL issues on EPYC 7551

Question asked by jameskap on Aug 4, 2017
Latest reply on Jan 31, 2018 by dipak

Hi All,

 

I am seeing extremely poor performance using OpenCL on an EPYC 7551. I can't imagine this is intended as it is far slower in our testing than my old E5-2695 v3 machines.

 

See the clinfo below. The max work item size looks incredibly low. Likewise the max clock speed is 1200MHz.  I am running Ubuntu 17.04 with AMD-APP-SDK-v3.0.130.136-GA...

 

 

 

Number of platforms                               1

  Platform Name                                   AMD Accelerated Parallel Processing

  Platform Vendor                                 Advanced Micro Devices, Inc.

  Platform Version                                OpenCL 2.0 AMD-APP (1800.8)

  Platform Profile                                FULL_PROFILE

  Platform Extensions                             cl_khr_icd cl_amd_event_callback cl_amd_offline_devices

  Platform Extensions function suffix             AMD

 

 

  Platform Name                                   AMD Accelerated Parallel Processing

Number of devices                                 1

  Device Name                                     AMD EPYC 7551 32-Core Processor

  Device Vendor                                   AuthenticAMD

  Device Vendor ID                                0x1002

  Device Version                                  OpenCL 1.2 AMD-APP (1800.8)

  Driver Version                                  1800.8 (sse2,avx)

  Device OpenCL C Version                         OpenCL C 1.2

  Device Type                                     CPU

  Device Profile                                  FULL_PROFILE

  Device Board Name (AMD)

  Device Topology (AMD)                           (n/a)

  Max compute units                               128

  Max clock frequency                             1200MHz

  Device Partition                                (core, cl_ext_device_fission)

    Max number of sub-devices                     128

    Supported partition types                     equally, by counts, by affinity domain

    Supported affinity domains                    L3 cache, L2 cache, L1 cache, next partitionable

    Supported partition types (ext)               equally, by counts, by affinity domain

    Supported affinity domains (ext)              L3 cache, L2 cache, L1 cache, next fissionable

  Max work item dimensions                        3

  Max work item sizes                             1024x1024x1024

  Max work group size                             1024

  Preferred work group size multiple              1

  Preferred / native vector sizes

    char                                                16 / 16

    short                                                8 / 8

    int                                                  4 / 4

    long                                                 2 / 2

    half                                                 4 / 4        (n/a)

    float                                                8 / 8

    double                                               4 / 4        (cl_khr_fp64)

  Half-precision Floating-point support           (n/a)

  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                              270432862208 (251.9GiB)

  Error Correction support                        No

  Max memory allocation                           67608215552 (62.97GiB)

  Unified memory for Host and Device              Yes

  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                        32768

  Global Memory cache line                        64 bytes

  Image support                                   Yes

    Max number of samplers per kernel             16

    Max size for 1D images from buffer            65536 pixels

    Max 1D or 2D image array size                 2048 images

    Max 2D image size                             8192x8192 pixels

    Max 3D image size                             2048x2048x2048 pixels

    Max number of read image args                 128

    Max number of write image args                64

  Local memory type                               Global

  Local memory size                               32768 (32KiB)

  Max constant buffer size                        65536 (64KiB)

  Max number of constant args                     8

  Max size of kernel argument                     4096 (4KiB)

  Queue properties

    Out-of-order execution                        No

    Profiling                                     Yes

  Prefer user sync for interop                    Yes

  Profiling timer resolution                      1ns

  Profiling timer offset since Epoch (AMD)        1501862602024150536ns (Fri Aug  4 09:03:22 2017)

  Execution capabilities

    Run OpenCL kernels                            Yes

    Run native kernels                            Yes

    SPIR versions                                 1.2

  printf() buffer size                            65536 (64KiB)

  Built-in kernels

  Device Available                                Yes

  Compiler Available                              Yes

  Linker Available                                Yes

  Device Extensions                               cl_khr_fp64 cl_amd_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_gl_sharing cl_ext_device_fission cl_amd_device_attribute_query cl_amd_vec3 cl_amd_printf cl_amd_media_ops cl_amd_media_ops2 cl_amd_popcnt cl_khr_spir cl_khr_gl_event

 

 

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)  Success (1)

    Platform Name                                 AMD Accelerated Parallel Processing

    Device Name                                   AMD EPYC 7551 32-Core Processor

  clCreateContextFromType(NULL, CL_DEVICE_TYPE_GPU)  No devices found in platform

  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                                   AMD EPYC 7551 32-Core Processor

 

 

ICD loader properties

  ICD loader Name                                 OpenCL ICD Loader

  ICD loader Vendor                               OCL Icd free software

  ICD loader Version                              2.2.11

  ICD loader Profile                              OpenCL 2.1

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