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[kalab1998]

I'm studying OpenCL now. I'd like to program like clinfo command. And I write code as follows on AMDAPP 2.8.1. but this code is wrong running.

Concretely, I get an information when this program call clGetDeviceInfo() on core i5-430UM and no GPU machine at first time,

code:

ret = clGetDeviceInfo( device_id[dv], CL_DEVICE_TYPE, MAX_MSG_SIZE, (void*)(&msg_uint), &msglen);
printf( "  ret = %d, msg = %d\n", ret, msg_uint);

print:

ret = 0, msg = 2

but I don't get any information and return code -33 when this program call clGetDeviceInfo() at second time.

code:

ret = clGetDeviceInfo( device_id[dv], CL_DEVICE_VENDOR, MAX_MSG_SIZE, (void*)msg, &msglen);
printf( "  ret = %d, msg = %s\n, ret, msg);

print:

ret = -33, msg = ...(depends memory status)

Please teach me where is my code wrong.

Program Code:

#include <stdio.h>
#include <stdlib.h>

#ifdef __APPLE__
#include <OpenCL/opencl.h>
#else
#include <CL/cl.h>
#endif

#define MAX_MSG_SIZE 256
#define MAX_PLATFORMS 16
#define MAX_DEVICES 256

int main()
{
  cl_platform_id platform_id[ MAX_PLATFORMS];
  cl_platform_info platform_info;
  cl_uint platforms_num;

  cl_device_id device_id[ MAX_DEVICES];
  cl_uint devices_num;

  cl_uint dummy;
  cl_int ret;
 
  char msg[ MAX_MSG_SIZE];
  size_t msglen;
  cl_uint msg_uint;
  cl_ulong msg_ulong;
  size_t msg_dim[ MAX_MSG_SIZE];
 
  ret = clGetPlatformIDs( MAX_PLATFORMS, platform_id, &platforms_num);

  for ( int pf = 0; pf < platforms_num; pf++) {
    printf( "Platform %d:\n", pf);
    ret = clGetPlatformInfo( platform_id[pf], CL_PLATFORM_PROFILE,
                 MAX_MSG_SIZE, (void*)msg, &msglen);
    printf( "  PLATFORM_PROFILE\t%s\n", msg);
    ret = clGetPlatformInfo( platform_id[pf], CL_PLATFORM_VERSION,
                 MAX_MSG_SIZE, (void*)msg, &msglen);
    printf( "  PLATFORM_VERSION\t%s\n", msg);
    ret = clGetPlatformInfo( platform_id[pf], CL_PLATFORM_NAME,
                 MAX_MSG_SIZE, (void*)msg, &msglen);
    printf( "  PLATFORM_NAME\t\t%s\n", msg);
    ret = clGetPlatformInfo( platform_id[pf], CL_PLATFORM_VENDOR,
                 MAX_MSG_SIZE, (void*)msg, &msglen);
    printf( "  PLATFORM_VENDOR\t%s\n", msg);
    ret = clGetPlatformInfo( platform_id[pf], CL_PLATFORM_EXTENSIONS,
                 MAX_MSG_SIZE, (void*)msg, &msglen);
    printf( "  PLATFORM_EXTENTIONS\t%s\n", msg);
   
    ret = clGetDeviceIDs( platform_id[pf], CL_DEVICE_TYPE_ALL, MAX_DEVICES,
              device_id, &devices_num);

    for ( int dv = 0; dv < devices_num; dv++) {
      printf( "platform %d: device %d:\n", pf, dv);
      ret = clGetDeviceInfo( device_id[dv], CL_DEVICE_TYPE,
                 MAX_MSG_SIZE, (void*)(&msg_uint), &msglen);
      printf( "  ret = %d, dvid = %d\n", ret, device_id[dv]);
      printf( "  DEVICE_TYPE\t%d ", msg_uint);
      switch ( msg_uint) {
      case CL_DEVICE_TYPE_CPU:
    printf( "CPU\n");
    break;
      case CL_DEVICE_TYPE_GPU:
    printf( "GPU\n");
    break;
      case CL_DEVICE_TYPE_ACCELERATOR:
    printf( "ACCELERATOR\n");
    break;
      case CL_DEVICE_TYPE_CUSTOM:
    printf( "CUSTOM\n");
    break;
      default:
    printf( "\n");
      }

      ret = clGetDeviceInfo( device_id[dv], CL_DEVICE_VENDOR,
                 MAX_MSG_SIZE, (void*)msg, &msglen);
      printf( "  ret = %d, dvid = %d\n", ret, device_id[dv]);
      printf( "  DEVICE_VENDOR\t%s\n", msg);
      ret = clGetDeviceInfo( device_id[dv], CL_DEVICE_NAME,
                 MAX_MSG_SIZE, (void*)msg, &msglen);
      printf( "  DEVICE_NAME\t%s\n", msg);
      ret = clGetDeviceInfo( device_id[dv], CL_DRIVER_VERSION,
                 MAX_MSG_SIZE, (void*)msg, &msglen);
      printf( "  DRIVER_VERSION\t%s\n", msg);
      ret = clGetDeviceInfo( device_id[dv], CL_DEVICE_PROFILE,
                 MAX_MSG_SIZE, (void*)msg, &msglen);
      printf( "  DEVICE_PROFILE\t%s\n", msg);
      ret = clGetDeviceInfo( device_id[dv], CL_DEVICE_VERSION,
                 MAX_MSG_SIZE, (void*)msg, &msglen);
      printf( "  DEVICE_VERSION\t%s\n", msg);
      ret = clGetDeviceInfo( device_id[dv], CL_DEVICE_OPENCL_C_VERSION,
                 MAX_MSG_SIZE, (void*)msg, &msglen);
      printf( "  DEVICE_OPENCL_C_VERSION\t%s\n", msg);
      ret = clGetDeviceInfo( device_id[dv], CL_DEVICE_EXTENSIONS,
                 MAX_MSG_SIZE, (void*)msg, &msglen);
      printf( "  DEVICE_EXTENSIONS\t%s\n", msg);

    }
    /*
    ret = clGetDeviceIDs( platform_id[ pf], CL_DEVICE_TYPE_ALL, 1,
              &device_id, &devices_num);
    ret = clGetDeviceIDs( platform_id[ pf], CL_Device_TYPE_ALL, devices_num,
              &device_id, &dummy);
    */
  }
  return 0;
}

[himanshu_gautam]

Check cl.h file for meaning of error code. Also check value of return after running the OpenCL APIs.

[kalab1998]

I undertand that return code -33 means "CL_INVALID_DEVICE"

However, I don't know about reason. When follows this code calls clGetDeviceInfo() at first, it runs right, but when it calls clGetDeviceInfo() at second, it runs wrong. Why?

rewrite simply code:

#include <stdio.h>
#include <stdlib.h>

#ifdef __APPLE__
#include <OpenCL/opencl.h>
#else
#include <CL/cl.h>
#endif

#define MAX_MSG_SIZE 256
#define MAX_PLATFORMS 16
#define MAX_DEVICES 256

int main()
{
  cl_platform_id platform_id[ MAX_PLATFORMS];
  cl_platform_info platform_info;
  cl_uint platforms_num;

  cl_device_id device_id[ MAX_DEVICES];
  cl_uint devices_num;

  cl_uint dummy;
  cl_int ret;
 
  char msg[ MAX_MSG_SIZE];
  size_t msglen;
  cl_uint msg_uint;
  cl_ulong msg_ulong;
  size_t msg_dim[ MAX_MSG_SIZE];

  ret = clGetPlatformIDs( MAX_PLATFORMS, platform_id, &platforms_num);

  for ( int pf = 0; pf < platforms_num; pf++) {
    ret = clGetDeviceIDs( platform_id[pf], CL_DEVICE_TYPE_ALL, MAX_DEVICES, device_id, &devices_num);

    for ( int dv = 0; dv < devices_num; dv++) {
      printf( "platform %d: device %d:\n", pf, dv);
      ret = clGetDeviceInfo( device_id[dv], CL_DEVICE_TYPE, MAX_MSG_SIZE, (void*)(&msg_uint), &msglen);
      printf( "  ret = %d, dvid = %d, msg_uint = %d\n", ret, msg_uint, device_id[dv]);
      ret = clGetDeviceInfo( device_id[dv], CL_DEVICE_VENDOR, MAX_MSG_SIZE, (void*)msg, &msglen);
      printf( "  ret = %d, dvid = %d, msg = %s\n", ret, device_id[dv], msg);
    }
  }
  return 0;
}

results:

platform 0: device 0:
  ret = 0, dvid = 0, msg_uint = 2
  ret = -33, dvid = 0, msg =

[himanshu_gautam · Accepted solution]

Your code is behaving bit strange. Probably I need to file a bug.

On linux machine, it was not giving any error in return code, but the loop is becoming infinite somehow. The code worked fine after these changes:

for ( int pf = 0; pf < platforms_num; pf++) {

    ret = clGetDeviceIDs( platform_id[pf], CL_DEVICE_TYPE_ALL, MAX_DEVICES, device_id, &devices_num);

    printf( "  ret = %d pf:%d\n", ret,pf);

    for ( int dv = 0; dv < devices_num; dv++) {

      printf( "platform %d: device %d:\n", pf, dv);

        cl_device_type devType;

      ret = clGetDeviceInfo( device_id[dv], CL_DEVICE_TYPE, sizeof(cl_device_type), (void*)(&devType), NULL);

      printf( "  ret = %d, dvid = %d, msg_uint = %d\n", ret, msg_uint, device_id[dv]);

      ret = clGetDeviceInfo( device_id[dv], CL_DEVICE_VENDOR, MAX_MSG_SIZE, (void*)msg, &msglen);

      printf( "  ret = %d, dvid = %d, msg = %s\n", ret, device_id[dv], msg);

      scanf("%d",&ret);

    }

  }

Also you should check AMD APP SDK Samples to know how to use the API in a less confusing manner.

[himanshu_gautam]

The issue was with msg_uint variable passed for CL_DEVICE_TYPE.

msg_uint is a cl_uint which is 4 bytes on my machine. But CL_DEVICE_TYPE property is a cl_device_type object, which is 8 bytes. So a memory corruption was happening.

Your code did not gave any error for me on windows. I was using Win7 64, Cat 13.6 beta, HD 7870 GPU with SDK 2.8.1

[kalab1998]

I was preoccupied with the handling of the multi-device and misunderstood it about message size.
Your code runs right.

Thank you for advice.

himanshu.gautam による書き込み:

Your code is behaving bit strange. Probably I need to file a bug.

On linux machine, it was not giving any error in return code, but the loop is becoming infinite somehow. The code worked fine after these changes:

(snip)

      cl_device_type devType;

      ret = clGetDeviceInfo( device_id[dv], CL_DEVICE_TYPE, sizeof(cl_device_type), (void*)(&devType),

(snip)

Also you should check AMD APP SDK Samples to know how to use the API in a less confusing manner.