6 Replies Latest reply on May 28, 2015 8:06 AM by dipak

    wrong results running OpenCl Helloworld sample (AMD SDK)

    evoliptic

      hello everybody,
      as a completely newcomer to OpenCl and such, i wanted to try to run some samples before getting into source. So basically, here is the result of the execution of the helloworld sample from the samples we get when we have extracted the auto installer :

      the execution of the helloworld sample

      input string:

      GdkknVnqkc

       

      output string:

      `´┐ŻB

      Passed!

       

      In fact, i get completely random characters as output.

       

      However, i think my installation is correct :

      here is my os (command uname + cat /etc/os-release):

      Linux x86_64 GNU/Linux | openSUSE 13.1 | kernel: 3.11.10-29-desktop

       

      here is the result of clinfo command (sorry i did not find anything to include a personnal txt file)

      clinfo command
      Number of platforms:    1
        Platform Profile:    FULL_PROFILE
        Platform Version:    OpenCL 2.0 AMD-APP (1642.5)
        Platform Name:    AMD Accelerated Parallel Processing
        Platform Vendor:    Advanced Micro Devices, Inc.
        Platform Extensions:    cl_khr_icd cl_amd_event_callback cl_amd_offline_devices

       

       

        Platform Name:    AMD Accelerated Parallel Processing
      Number of devices:    2
        Device Type:    CL_DEVICE_TYPE_GPU
        Vendor ID:    1002h
        Board name: 
        Device Topology:    PCI[ B#2, D#0, F#0 ]
        Max compute units:    44
        Max work items dimensions:    3
      Max work items[0]:    256
      Max work items[1]:    256
      Max work items[2]:    256
        Max work group size:    256
        Preferred vector width char:    4
        Preferred vector width short:    2
        Preferred vector width int:    1
        Preferred vector width long:    1
        Preferred vector width float:    1
        Preferred vector width double:    1
        Native vector width char:    4
        Native vector width short:    2
        Native vector width int:    1
        Native vector width long:    1
        Native vector width float:    1
        Native vector width double:    1
        Max clock frequency:    930Mhz
        Address bits:    64
        Max memory allocation:    4244635648
        Image support:    Yes
        Max number of images read arguments:    128
        Max number of images write arguments:    64
        Max image 2D width:    16384
        Max image 2D height:    16384
        Max image 3D width:    2048
        Max image 3D height:    2048
        Max image 3D depth:    2048
        Max samplers within kernel:    16
        Max size of kernel argument:    1024
        Alignment (bits) of base address:    2048

        Minimum alignment (bytes) for any datatype:     128

        Single precision floating point capability

      Denorms:    No
      Quiet NaNs:    Yes
      Round to nearest even:    Yes
      Round to zero:    Yes
      Round to +ve and infinity:    Yes
      IEEE754-2008 fused multiply-add:    Yes
        Cache type:    Read/Write
        Cache line size:    64
        Cache size:    16384
        Global memory size:    16978542592
        Constant buffer size:    65536
        Max number of constant args:    8
        Local memory type:    Scratchpad
        Local memory size:    32768
        Max pipe arguments:    16
        Max pipe active reservations:    16
        Max pipe packet size:    4244635648
        Max global variable size:    3820172032

        Max global variable preferred total size:     16978542592

        Max read/write image args:    64
        Max on device events:    1024
        Queue on device max size:    524288
        Max on device queues:    1
        Queue on device preferred size:    16384
        SVM capabilities: 
      Coarse grain buffer:    Yes
      Fine grain buffer:    Yes
      Fine grain system:    No
      Atomics:    No
        Preferred platform atomic alignment:    0
        Preferred global atomic alignment:    0
        Preferred local atomic alignment:    0

        Kernel Preferred work group size multiple:     64

        Error correction support:    0
        Unified memory for Host and Device:    0
        Profiling timer resolution:    1
        Device endianess:    Little
        Available:    Yes
        Compiler available:    Yes
        Execution capabilities: 
      Execute OpenCL kernels:    Yes
      Execute native function:    No
        Queue on Host properties: 
      Out-of-Order:    No
      Profiling :    Yes
        Queue on Device properties: 
      Out-of-Order:    Yes
      Profiling :    Yes
        Platform ID:    0x7f543f7c9fd0
        Name:    Hawaii
        Vendor:    Advanced Micro Devices, Inc.
        Device OpenCL C version:    OpenCL C 2.0
        Driver version:    1642.5 (VM)
        Profile:    FULL_PROFILE
        Version:    OpenCL 2.0 AMD-APP (1642.5)
        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_atomic_counters_32 cl_amd_device_attribute_query cl_amd_vec3 cl_amd_printf cl_amd_media_ops cl_amd_media_ops2 cl_amd_popcnt cl_khr_image2d_from_buffer cl_khr_spir cl_khr_subgroups cl_khr_gl_event cl_khr_depth_images

       

       

        Device Type:    CL_DEVICE_TYPE_CPU
        Vendor ID:    1002h
        Board name: 
        Max compute units:    4
        Max work items dimensions:    3
      Max work items[0]:    1024
      Max work items[1]:    1024
      Max work items[2]:    1024
        Max work group size:    1024
        Preferred vector width char:    16
        Preferred vector width short:    8
        Preferred vector width int:    4
        Preferred vector width long:    2
        Preferred vector width float:    8
        Preferred vector width double:    4
        Native vector width char:    16
        Native vector width short:    8
        Native vector width int:    4
        Native vector width long:    2
        Native vector width float:    8
        Native vector width double:    4
        Max clock frequency:    3699Mhz
        Address bits:    64
        Max memory allocation:    33841593344
        Image support:    Yes
        Max number of images read arguments:    128
        Max number of images write arguments:    64
        Max image 2D width:    8192
        Max image 2D height:    8192
        Max image 3D width:    2048
        Max image 3D height:    2048
        Max image 3D depth:    2048
        Max samplers within kernel:    16
        Max size of kernel argument:    4096
        Alignment (bits) of base address:    1024

        Minimum alignment (bytes) for any datatype:     128

        Single precision floating point capability

      Denorms:    Yes
      Quiet NaNs:    Yes
      Round to nearest even:    Yes
      Round to zero:    Yes
      Round to +ve and infinity:    Yes
      IEEE754-2008 fused multiply-add:    Yes
        Cache type:    Read/Write
        Cache line size:    64
        Cache size:    32768
        Global memory size:    135366373376
        Constant buffer size:    65536
        Max number of constant args:    8
        Local memory type:    Global
        Local memory size:    32768
        Max pipe arguments:    16
        Max pipe active reservations:    16
        Max pipe packet size:    3776822272
        Max global variable size:    1879048192

        Max global variable preferred total size:     1879048192

        Max read/write image args:    64
        Max on device events:    0
        Queue on device max size:    0
        Max on device queues:    0
        Queue on device preferred size:    0
        SVM capabilities: 
      Coarse grain buffer:    Yes
      Fine grain buffer:    Yes
      Fine grain system:    Yes
      Atomics:    Yes
        Preferred platform atomic alignment:    0
        Preferred global atomic alignment:    0
        Preferred local atomic alignment:    0

        Kernel Preferred work group size multiple:     1

        Error correction support:    0
        Unified memory for Host and Device:    1
        Profiling timer resolution:    1
        Device endianess:    Little
        Available:    Yes
        Compiler available:    Yes
        Execution capabilities: 
      Execute OpenCL kernels:    Yes
      Execute native function:    Yes
        Queue on Host properties: 
      Out-of-Order:    No
      Profiling :    Yes
        Queue on Device properties: 
      Out-of-Order:    No
      Profiling :    No
        Platform ID:    0x7f543f7c9fd0
        Name:    Intel(R) Xeon(R) CPU E5-1630 v3 @ 3.70GHz
        Vendor:    GenuineIntel
        Device OpenCL C version:    OpenCL C 1.2
        Driver version:    1642.5 (sse2,avx)
        Profile:    FULL_PROFILE
        Version:    OpenCL 1.2 AMD-APP (1642.5)
        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

       

      Any idea from what it could come?

       

      thanks in advance,

        • Re: wrong results running OpenCl Helloworld sample (AMD SDK)
          dipak

          After the successful run, the "HelloWorld" sample should print "output string" as "HelloWorld". In the corresponding "helloworld" kernel code [file "HelloWorld_Kernel.cl" in same directory as the binary], it just adds 1 to each input character value.

          I'm not sure why you are getting the garbage string. However, as I guess, if the kernel fails to execute, the output buffer may contain garbage values and thus may print garbage output string. You know, its one of the earliest samples and trivial one, so, it lacks few error checking and messages. In the <APP SDK>/samples/opencl/cl/HelloWorld sample, you may check return status of the APIs to verify whether everything working fine or not. For example, you may check the value of the "status" for the below line. A non-zero value indicates an error.

          status = clEnqueueNDRangeKernel(commandQueue, kernel, 1, NULL, global_work_size, NULL, 0, NULL, NULL);

           

          BTW, did you try other samples? Are they working fine?

          If haven't tried yet, please run some other samples and see.

           

          Regards,