Actual source code: PetscMemcpy.c
1: /*$Id: PetscMemcpy.c,v 1.21 2001/03/23 23:25:45 balay Exp $*/
3: #include "petsc.h"
5: int main(int argc,char **argv)
6: {
7: PetscLogDouble x,y,z;
8: int i,ierr;
9: Scalar *A,*B;
11: PetscInitialize(&argc,&argv,0,0);
13: PetscMalloc(8000000*sizeof(Scalar),&A);
14: PetscMalloc(8000000*sizeof(Scalar),&B);
16: for (i=0; i<8000000; i++) {
17: A[i] = i%61897;
18: B[i] = i%61897;
19: }
20: /* To take care of paging effects */
21: PetscMemcpy(A,B,sizeof(Scalar)*0);
22: PetscGetTime(&x);
24: PetscGetTime(&x);
25: /*
26: PetscMemcpy(A,B,sizeof(Scalar)*8000000);
27: PetscMemcpy(A,B,sizeof(Scalar)*8000000);
28: PetscMemcpy(A,B,sizeof(Scalar)*8000000);
29: PetscMemcpy(A,B,sizeof(Scalar)*8000000);
30: PetscMemcpy(A,B,sizeof(Scalar)*8000000);
31: PetscMemcpy(A,B,sizeof(Scalar)*8000000);
32: PetscMemcpy(A,B,sizeof(Scalar)*8000000);
33: PetscMemcpy(A,B,sizeof(Scalar)*8000000);
34: PetscMemcpy(A,B,sizeof(Scalar)*8000000);
35: PetscMemcpy(A,B,sizeof(Scalar)*8000000); */
36: { int j;
37: for (j = 0; j<10; j++) {
38: for (i=0; i<8000000; i++) {
39: B[i] = A[i];
40: }
41: }}
43: PetscGetTime(&y);
44: PetscMemcpy(A,B,sizeof(Scalar)*0);
45: PetscMemcpy(A,B,sizeof(Scalar)*0);
46: PetscMemcpy(A,B,sizeof(Scalar)*0);
47: PetscMemcpy(A,B,sizeof(Scalar)*0);
48: PetscMemcpy(A,B,sizeof(Scalar)*0);
49: PetscMemcpy(A,B,sizeof(Scalar)*0);
50: PetscMemcpy(A,B,sizeof(Scalar)*0);
51: PetscMemcpy(A,B,sizeof(Scalar)*0);
52: PetscMemcpy(A,B,sizeof(Scalar)*0);
53: PetscMemcpy(A,B,sizeof(Scalar)*0);
54: PetscGetTime(&z);
56: fprintf(stdout,"%s : n","PetscMemcpy");
57: fprintf(stdout," %-11s : %e MB/sn","Bandwidth",10.0*8*8/(y-x));
58: fprintf(stdout," %-11s : %e secn","Latency",(z-y)/10.0);
59: fprintf(stdout," %-11s : %e secn","Per Scalar",(2*y-x-z)/8000000.0);
61: PetscFinalize();
62: return(0);
63: }