reduction.br

用于GPU通用计算的编程语言BrookGPU 0.4

#include <stdio.h>
#ifdef WIN32
#include <windows.h>
#else
#include <unistd.h>
void Sleep(int n) {
  usleep(1000*n);
}
#endif

#include "main.h"
#include "reduction.h"

int discard;

reduce void reductionKernel(float4 x<>, reduce float4 result<>) {
  result += x;
}

kernel void reductionRegKernel(float4 x<>, float4 constant, out float4 result<>) {
  result = x + constant;
  if (constant.x) discard;
}

kernel void forceGPUFlush(float4 input<>, out float4 result<>) {
  result = input;
}

void do_reduction(int dim, int simReduceReg, int iterations, int* time) {
  
  int i;
  float* x;
  float4 result;
  float4 constant;
  float sum;
  float4 xStrm<dim,dim>;
  float4 yStrm<dim,dim>;
  float4 resultStrm<1>;
  
  float4 flush[1];
  float4 flushStrm<1>;
  
  x = (float*)malloc(sizeof(float)*dim*dim*4);
  
  for (i=0;i<dim*dim*4;i++)
    x[i] = 1.0f;
  
  constant.x = constant.y = constant.z = constant.w = 2.0f;
  
  streamRead(xStrm, x);
  forceGPUFlush(xStrm, flushStrm);
  streamRead(flushStrm, flush);
  
  // wait for a little, make sure system is ready
  //Sleep(1);
  
  if (!simReduceReg) {
    
    start = GetTimeTSC();        
    for (i=0;i<iterations;i++) {    
      reductionKernel(xStrm, resultStrm);
      sum = result.x + result.y + result.z + result.w;
    }    
    stop = GetTimeTSC();
    
    //    if (fabs(sum - (4.0f*dim*dim)) > .05 )
    //  printf("Error!\n");	
    
    // printf("sum = %f\n", sum);
    
  } else {
    
    start = GetTimeTSC();
    for (i=0;i<iterations;i++) {
      reductionRegKernel(xStrm, constant, yStrm);		
    }     	
    
    forceGPUFlush(yStrm, flushStrm);
    streamWrite(flushStrm, flush);	   	
    stop = GetTimeTSC();              
    
  }
  
  //printf("%d\n", (int)(stop - start) );
  
  *time = (int)(CyclesToUsecs(stop-start));  
  
  free(x);
  
}




void Reduction_Time(int length) {


  int size; 
  int simReduceReg;
  int usec;
  int iterations = 200;

  simReduceReg = 0;

  do_reduction(512, simReduceReg, 1, &usec);

  printf("(* size *)  (* usec *)\n");
  for (size = 2; size<=length; size*=2) {
    do_reduction(size, simReduceReg, iterations, &usec);
    printf("%8d    %.5f         (* kernel reduce *)\n",
	   4*size*size, (float)usec / (float)iterations );
  }

  printf("\n\n\n");


  simReduceReg = 1;
  do_reduction(size, simReduceReg, iterations, &usec);


  printf("(* size *)  (* usec *)\n");
  for (size = 2; size<=length; size*=2) {
    do_reduction(size, simReduceReg, iterations, &usec);
    printf("%8d    %.5f         (* reduce reg*)\n", 4*size*size, (float)usec / (float)iterations );
  }
  
 


}