Chapter 2, example 2: Testing device extensions

[Petr Schreiber]

The second strange new word from OpenCL world is "device". We already learned there can be 1 or more OpenCL platforms on your PC.

Each of them can have 1 or more devices.

Device is the actual hardware the OpenCL C code runs on.

If you have 2 GPUs from same vendor on your PC, you have 1 platform but 2 devices.

OpenCL allows you to choose which device(s) you want to use for calculation - you can pick one or all.

The example code below lists device names, types and extensions.

Comparing to the book original, I added going through devices for each platform and added their name and type (GPU/CPU) with OpenCL version support.

So what I learn?
How to enumerate OpenCL devices for platforms on your PC.

So what I need to run it?
You will need the latest ThinBASIC and OpenCL headers to run it + of course modern GPU or CPU.

Code listing (full code in attachement!)

' -- NOTE: Enhanced to list the info for all installed platforms, with name + types of devices

Uses "Console"

#INCLUDE "%APP_INCLUDEPATH%/cl/cl.tBasicU"

Function TBMain()

   /* Host/device data structures */
   tcl_platform_id platforms()    
   tcl_platform_id platform
   tcl_uint        num_platforms
   tcl_device_id   devices()   
   tcl_uint        num_devices, addr_data
   tcl_int         i, ErrCl, p
   tcl_device_type deviceType  

   /* Extension data */
   String name_data = Repeat$(48, " ")
   String ext_data = Repeat$(4096, " ") 
   String deviceTypeDescriptor

   /* Find number of platforms */
   ErrCL = clGetPlatformIDs(1, ByVal NULL, num_platforms)
   If (ErrCL < 0) Then        
      pError("Couldn't find any platforms.")            
      APP_SetReturnCode(1) : WaitKey : Exit Function
   End If
  
   /* Access all installed platforms */
   ReDim platforms(num_platforms)
   clGetPlatformIDs(num_platforms, platforms, ByVal NULL)        
   
   /* Platform name */
   Dim szName As Asciiz * 512
   Dim versionCL As Asciiz * 64
   
   For p = 1 To num_platforms   
     platform = platforms(p)
      
     clGetPlatformInfo(platform,             
        CL_PLATFORM_NAME, sizeof(szName), ByVal VarPtr(szName), ByVal NULL)   
     PrintL "List of devices for platform #"+Format$(p) + ": " + szName
   
     /* Determine number of connected devices */
     ErrCl = clGetDeviceIDs(platform, CL_DEVICE_TYPE_ALL, 1, ByVal NULL, num_devices)
     If (ErrCl < 0) Or num_devices = 0 Then                
        pError("Couldn't find any devices")        
        
     Else
            
       /* Access connected devices */  
       ReDim devices(num_devices)
       clGetDeviceIDs(platform, CL_DEVICE_TYPE_ALL,             
             num_devices, devices, ByVal NULL)                
       
       /* Obtain data for each connected device */
       For i = 1 To num_devices
       
          ErrCl = clGetDeviceInfo(devices(i), CL_DEVICE_NAME,         
                Len(name_data), ByVal StrPtr(name_data), ByVal NULL)                
                
          If (ErrCl < 0) Then        
             pError("Couldn't read extension data")
             APP_SetReturnCode(1) : WaitKey : Exit Function
          End If                                                         
          
          
          ErrCl = clGetDeviceInfo(devices(i), CL_DEVICE_VERSION,         
              SizeOf(versionCL), ByVal StrPtr(versionCL), ByVal NULL)             
          
          clGetDeviceInfo(devices(i), CL_DEVICE_ADDRESS_BITS,     
                SizeOf(ext_data), addr_data, ByVal NULL)
  
          
          clGetDeviceInfo(devices(i), CL_DEVICE_TYPE,     
                SizeOf(deviceType), ByVal VarPtr(deviceType), ByVal NULL)
                
          deviceTypeDescriptor = ""
          If Bit_Get(deviceType, LogB(2, CL_DEVICE_TYPE_DEFAULT)) Then deviceTypeDescriptor += "DEFAULT "
          If Bit_Get(deviceType, LogB(2, CL_DEVICE_TYPE_CPU)) Then deviceTypeDescriptor += "CPU "
          If Bit_Get(deviceType, LogB(2, CL_DEVICE_TYPE_GPU)) Then deviceTypeDescriptor += "GPU "
          If Bit_Get(deviceType, LogB(2, CL_DEVICE_TYPE_ACCELERATOR)) Then deviceTypeDescriptor += "ACCELERATOR "
                  
          clGetDeviceInfo(devices(i), CL_DEVICE_EXTENSIONS,         
                Len(ext_data), ByVal StrPtr(ext_data), ByVal NULL)            
    
          PrintL StrFormat$("NAME: {1}"+$CRLF+"TYPE: {2} ({3})"+$CRLF+"ADDRESS_WIDTH: {4}"+$CRLF+"EXTENSIONS: {5}", 
                Trim$(name_data), deviceTypeDescriptor, versionCL, Trim$(addr_data), $CRLF+Replace$(TrimFull$(ext_data), " ", $CRLF))
                
          PrintL           
        Next
      End If 
      
     PrintL
   Next
   PrintL "Press any key to continue..."   
   WaitKey
   APP_SetReturnCode(0)                            

End Function

Function pError( sError As String )

  Console_SetTextAttribute(%CONSOLE_FOREGROUND_RED | %CONSOLE_FOREGROUND_INTENSITY)
  PrintL sError
  Console_SetTextAttribute(%CONSOLE_FOREGROUND_RED | %CONSOLE_FOREGROUND_GREEN | %CONSOLE_FOREGROUND_BLUE)
  
End Function

[REDEBOLT]

I am unable to find the file "OpenCL.DLL" on my computer.
Can my computer use a version of an existing file?
If so, where can I download it?

Here is attachment of my computer's configuration:

[Petr Schreiber]

Hi,

your hardware should be strong enough. Can you find atiocl.dll on your PC?
If not, you could consider downloading AMD APP SDK. Here is direct link to 32bit version:
http://developer.amd.com/Downloads/A...Windows-32.exe

It should contain opencl.dll or atiocl.dll. I remember I used it 3 years ago, now I have Intel and NVIDIA based system, so cannot test.

If I remember correctly ATi deprecated the support for OpenCL on Radeon HD 4xxx series (which you have), but you still should be able to run it on your CPU.

I think I took atiocl.dll, renamed it to opencl.dll and moved to the same directory as thinbasic.exe is located, but I am not sure if this step is still necessary, let me know how it went!


Petr

[kryton9]

Thanks for the new example and explanations Petr.