6 Replies Latest reply on May 7, 2012 7:10 PM by kbrafford

    Why does the GPU OpenCL context keep disappearing?

    kbrafford

      I was having trouble with the GPU context being there at first, then disappearing after awhile.  I couldn't figure out how to force it to vanish, it just would after some time.

       

      So I uninstalled the AMD driver that the auto-detect application installed, and reinstalled the version that came with my card.  At first the GPU context was there, but now it's gone again!  What is going on?

       

      --Keith Brafford

        • Re: Why does the GPU OpenCL context keep disappearing?
          gautam.himanshu

          What do you mean by context has disappeared?

          Are you running some code, which is giving "no context" type error?

          • Re: Why does the GPU OpenCL context keep disappearing?
            kbrafford

            I should be clearer.  It's not a context that vanishes.  It's the GPU device.  I still get the AMD Phenom II CPU device in the list, but no Tahiti.

            • Re: Why does the GPU OpenCL context keep disappearing?
              kbrafford

              Ok, I rebooted and...even from a fresh start I gets no GPU device. 

               

              So I reinstalled driver version 12.3 from the previous versions link:

              http://support.amd.com/us/gpudownload/windows/previous/12/Pages/radeon.aspx?os=Windows%20Vista%20-%2064-Bit%20Edition&rev=12.3

               

              And then the GPU showed back up.  I have no idea how many minutes or hours the GPU device will be available, before it disappears again:

               

              C:\Users\Keith>clinfo
              Number of platforms:                             1
                Platform Profile:                              FULL_PROFILE
                Platform Version:                              OpenCL 1.2 AMD-APP (923.1)
                Platform Name:                                 AMD Accelerated Parallel Proces
              sing
                Platform Vendor:                               Advanced Micro Devices, Inc.
                Platform Extensions:                           cl_khr_icd cl_amd_event_callbac
              k cl_amd_offline_devices cl_khr_d3d10_sharing
              
              
                Platform Name:                                 AMD Accelerated Parallel Proces
              sing
              Number of devices:                               2
                Device Type:                                   CL_DEVICE_TYPE_GPU
                Device ID:                                     4098
                Board name:                                    AMD Radeon HD 7900 Series
                Max compute units:                             32
                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:                   16
                Preferred vector width short:                  8
                Preferred vector width int:                    4
                Preferred vector width long:                   2
                Preferred vector width float:                  4
                Preferred vector width double:                 2
                Native vector width char:                      16
                Native vector width short:                     8
                Native vector width int:                       4
                Native vector width long:                      2
                Native vector width float:                     4
                Native vector width double:                    2
                Max clock frequency:                           925Mhz
                Address bits:                                  32
                Max memory allocation:                         536870912
                Image support:                                 Yes
                Max number of images read arguments:           128
                Max number of images write arguments:          8
                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:                   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:                            2147483648
                Constant buffer size:                          65536
                Max number of constant args:                   8
                Local memory type:                             Scratchpad
                Local memory size:                             32768
                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 properties:
                  Out-of-Order:                                No
                  Profiling :                                  Yes
                Platform ID:                                   000007FED5202A08
                Name:                                          Tahiti
                Vendor:                                        Advanced Micro Devices, Inc.
                Device OpenCL C version:                       OpenCL C 1.2
                Driver version:                                CAL 1.4.1703 (VM)
                Profile:                                       FULL_PROFILE
                Version:                                       OpenCL 1.2 AMD-APP (923.1)
                Extensions:                                    cl_khr_fp64 cl_amd_fp64 cl_khr_
              global_int32_base_atomics cl_khr_global_int32_extended_atomics cl_khr_local_int3
              2_base_atomics cl_khr_local_int32_extended_atomics cl_khr_3d_image_writes cl_khr
              _byte_addressable_store cl_khr_gl_sharing cl_ext_atomic_counters_32 cl_amd_devic
              e_attribute_query cl_amd_vec3 cl_amd_printf cl_amd_media_ops cl_amd_popcnt cl_kh
              r_d3d10_sharing
              
              
                Device Type:                                   CL_DEVICE_TYPE_CPU
                Device ID:                                     4098
                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:                  4
                Preferred vector width double:                 0
                Native vector width char:                      16
                Native vector width short:                     8
                Native vector width int:                       4
                Native vector width long:                      2
                Native vector width float:                     4
                Native vector width double:                    0
                Max clock frequency:                           3010Mhz
                Address bits:                                  64
                Max memory allocation:                         2147483648
                Image support:                                 Yes
                Max number of images read arguments:           128
                Max number of images write arguments:          8
                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:                                    65536
                Global memory size:                            8581414912
                Constant buffer size:                          65536
                Max number of constant args:                   8
                Local memory type:                             Global
                Local memory size:                             32768
                Kernel Preferred work group size multiple:     1
                Error correction support:                      0
                Unified memory for Host and Device:            1
                Profiling timer resolution:                    340
                Device endianess:                              Little
                Available:                                     Yes
                Compiler available:                            Yes
                Execution capabilities:
                  Execute OpenCL kernels:                      Yes
                  Execute native function:                     Yes
                Queue properties:
                  Out-of-Order:                                No
                  Profiling :                                  Yes
                Platform ID:                                   000007FED5202A08
                Name:                                          AMD Phenom(tm) II X4 940 Proces
              sor
                Vendor:                                        AuthenticAMD
                Device OpenCL C version:                       OpenCL C 1.2
                Driver version:                                2.0 (sse2)
                Profile:                                       FULL_PROFILE
                Version:                                       OpenCL 1.2 AMD-APP (923.1)
                Extensions:                                    cl_khr_fp64 cl_amd_fp64 cl_khr_
              global_int32_base_atomics cl_khr_global_int32_extended_atomics cl_khr_local_int3
              2_base_atomics cl_khr_local_int32_extended_atomics cl_khr_int64_base_atomics cl_
              khr_int64_extended_atomics cl_khr_byte_addressable_store cl_khr_gl_sharing cl_ex
              t_device_fission cl_amd_device_attribute_query cl_amd_vec3 cl_amd_printf cl_amd_
              media_ops cl_amd_popcnt cl_khr_d3d10_sharing