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scharupa
Staff
Staff

Application crash, Unhandled exception

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Hi,

I have written following program to find out SAD value (sum of absolute difference) in a given frame.

My kernel code is here......

The kernel works fine if the Frame_width=100 , Frame_height = 100, width = 64, height=64

The same kernel crashes if the Frame_width=500 , Frame_height = 500, width = 64, height=64

Any one has any idea. It's bit urgent for me...

void SAD_function(__global unsigned char *p1, __global unsigned char *p2, int height, int width, int frame_width, int frame_height, int id, __global int *out) {

  int count=0, offset=0, iteration=0;

  int SAD = 0, l=0;

  int  y=0, t=0, t1;

  t1 = (frame_width - width + 1);

  for(int iteration=0; iteration<=(frame_width-width) ; iteration++)  {

  int16 total16=0; y=0;

  for(int vh=iteration; vh < (height*frame_width);  ) {

  count =0;

  for(int vw=0; vw<width/16; vw++) {

  __global uchar* p1_i = p1 + vh + (id*frame_width);

  __global uchar* p2_i = p2 + y + (id*frame_width);

  uchar16 vp1 = vload16(0, p1_i);

  uchar16 vp2 = vload16(0, p2_i);

  short16 temp = convert_short16(abs_diff(vp1,vp2));

  total16 = total16+convert_int16(temp);

  count = count+1;

  vh=vh+16; y=y+16;

  }

  vh = vh + frame_width - (count*16) ;

  }

  SAD = total16.s0 +total16.s1 + total16.s2 + total16.s3 + total16.s4 +total16.s5 + total16.s6 + total16.s7 + total16.s8 + total16.s9 + total16.sa + total16.sb + total16.sc + total16.sd + total16.se + total16.sf;

  out[t + t1*id ]=SAD; t = t+1; SAD=0;

 

  }

  offset= offset+frame_width;

}

__kernel void SAD_value(__global unsigned char *p1, __global unsigned char *p2, int height, int width, int frame_width, int frame_height, __global int *out) {

  int id = get_global_id(0);

  int size = get_global_size(0);

  int wgid = get_group_id(0);

   SAD_function(p1,p2, height, width, frame_width, frame_height, id, out);

}

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ravkum
Staff
Staff

Re: Application crash, Unhandled exception

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Hi,

Change the clEnqueueNDRangeKernel call as below:

ret = clEnqueueNDRangeKernel(command_queue, kernel, 1, NULL, &global_item_size, NULL, 0, NULL, &ndrEvt);

if (ret != CL_SUCCESS) {

          printf("Error EnqueueNDRangeKernel error code: %d\n", ret);

          exit(1);

}

Also, you should check for the error code for all the openCL APIs.

I do not get crash for 600 frame width and height. The above code fixed the problem.

Regards,

Ravi

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8 Replies
scharupa
Staff
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Re: Application crash, Unhandled exception

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Can some look into it. It's urgent for me.

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ravkum
Staff
Staff

Re: Application crash, Unhandled exception

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Hi,

Have you checked if the p1, p2 index is going out-of-bound?

Other than this, I don't see anything that is obvious to go wrong. Could you give the host code as well so I can reproduce the issue here?

Off-topic, I would recommend you declare the private variables outside the loop and re-use them.

Regards,

Ravi

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scharupa
Staff
Staff

Re: Application crash, Unhandled exception

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Hi Ravi,

Here attaching the C code, DropBox link.

https://www.dropbox.com/s/vh30d9smndmvbbf/SAD_in_19x10_find-min_block_64x64.rar

pls check it once.

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ravkum
Staff
Staff

Re: Application crash, Unhandled exception

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Hi,

I checked your code. The problem is in setting the local_item_size while calling clEnqueueNDRangeKernel.

When the frame_width and height is 500, the local_size becomes 437. The maximum allowed local_size is 256. In case the frame_width and height is 100, the local_item_size is 37, which is fine.

To get this work, you can pass NULL instead of local_item_size.

Regards,

Ravi

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scharupa
Staff
Staff

Re: Application crash, Unhandled exception

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Thanks Ravi.

I have modified host code as you suggested, local_item_size=NULL, its still not working.

Frame_width =600

Frame_height =600

width = 64

height =64

Result: App crash

Could you help me to fix it?

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scharupa
Staff
Staff

Re: Application crash, Unhandled exception

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The crash occurs at following line in host code.

    ret = clEnqueueWriteBuffer(command_queue, out_mem_obj, CL_TRUE, 0,

            t * sizeof(int), out, 0, NULL, NULL);

Any idea?

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ravkum
Staff
Staff

Re: Application crash, Unhandled exception

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Hi,

Change the clEnqueueNDRangeKernel call as below:

ret = clEnqueueNDRangeKernel(command_queue, kernel, 1, NULL, &global_item_size, NULL, 0, NULL, &ndrEvt);

if (ret != CL_SUCCESS) {

          printf("Error EnqueueNDRangeKernel error code: %d\n", ret);

          exit(1);

}

Also, you should check for the error code for all the openCL APIs.

I do not get crash for 600 frame width and height. The above code fixed the problem.

Regards,

Ravi

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scharupa
Staff
Staff

Re: Application crash, Unhandled exception

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Thanks Ravi.

The binaries which you shared(personally ) ware working fine with the changes.

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