Hi,
I am running into a bizarre memory issue: I do not appear to be
able to allocate 8GB of memory into a single array:
===<int_malloc.c>================================================
#include <stdio.h>
#include <stdlib.h>
int main(int argc, char *argv[]){
long int i, n;
long int *m;
n = 1024*1024*1024*sizeof(long int);
for (i = 1; i <= n; i*=2) {
m = (long *) malloc(i);
if (m == NULL) {
fprintf(stderr, "allocation of %li bytes failed.\n", i);
exit(-1);
}
free(m);
}
}
===</int_malloc>=================================================
# gcc -m64 int_malloc.c
# ./a.out
allocation of 8589934592 bytes failed.
This is with a 2.6.5 kernel (SLES 9).
If I compile the same program under kernel 2.6.16.27 (openSuSE 10.2),
the program completes without problem.
Under either OS I can allocate, e.g., 5 arrays of 4GB each within the
same program without problem.
Where does this limit of 8GB for a single array come from?
Is it in the kernel? If yes, can it be changed, e.g., through a sysctl?
Which one?
Cheers,
Martin
--
Martin Siegert
Head, [EMAIL PROTECTED]
WestGrid Site Lead
Academic Computing Services phone: (604) 291-4691
Simon Fraser University fax: (604) 291-4242
Burnaby, British Columbia email: [EMAIL PROTECTED]
Canada V5A 1S6
_______________________________________________
Beowulf mailing list, Beowulf@beowulf.org
To change your subscription (digest mode or unsubscribe) visit
http://www.beowulf.org/mailman/listinfo/beowulf
