2010/5/3 Juan Ángel Lorenzo <jalmailingli...@gmail.com>:
> Hi all,
>
> I'm using one of the perfmon's example codes, mont_dear.c, to test the
> accessed memory positions on a Itanium2 Montvale. Basically, what I do is to
> modify the do_test() function to store in a file the accessed memory
> positions. Later, I compare them with the sampled addresses given by the
> Event Address Registers (EARs). Surprisingly, all the sampled addresses are
> always lower than the ones accessed in the do_test() function. Am I doing
> something wrong? This is the modified function I use:
>
You have modified the program heavily. It is likely now your cache
misses are coming
from libc and fprintf() in particular. You don't need to save the
addresses in a file to
compare them. All you need to do is print the boundaries of the array.
I would even
move the allocation elsewhere so it would not interfere. Also be
careful with compiler
optimizations, the code is very simple and may be optimized away. I
would do something
slightly more complicated in the test loop, at least make sure the
data is used after the
loop is finished.
> long do_test(unsigned long size)
> {
> int i, sum = 0;
> int *array;
> int *addr;
>
> FILE *fd;
> fd = fopen("addresses.dat","w");
>
> printf("array size %.1fKB\n", (size*sizeof(int))/1024.0);
> array = (int *)malloc(size * sizeof(int));
>
> if (array == NULL ) {
> printf("line = %d No memory available!\n", __LINE__);
> exit(1);
> }
>
> for(i=0; i<size; i++) {
> array[i]=1;
> addr = array+i;
> fprintf(fd,"%p array[%d]: %d\n",addr,i,array[i]);
>
> }
>
> fclose(fd);
> return sum;
> }
>
>
> Thanks in advance for all the comments you can provide,
> Juan
>
>
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