Apple

Bob

------------ Orignial Post ----------------------------------

Begin forwarded message:

From: Bob Bader <email@hidden>
Date: November 3, 2005 2:30:49 PM EST
To: email@hidden
Subject: 64-bit question

I am an admin for a box that my department has users doing development work on. We have 8 gigs of ram in the machine and have been waiting to go to Tiger and 64-bit. I just upgraded the machine to tiger and my users are telling me the below conditions

Can anyone confirm this or tell me what is going on? why does this crash a 10.4 machine but not Linux.

I apologize if this is not the right forum for this question and would appreciate any ideas on where I can get my questions answered.

Thanks

Bob

---------------- Observations from my users -----------------------
1. The "top" command does not display the correct memory allocation status for a given process. To be precise, it is not able to show the values for memory greater than 4GB so it's a kind of hard to test high-mem applications. Looks like it's just the old 32bit "top", without 64bit capability.

2. We wrote and executed a custom C program to test the 64bit C compiler the system came with. It also tests 64bit environment and a system's general ability to handle high-mem apps. The application was able to allocate about 15GB on your test box and ... then the machine rebooted! Unacceptable!

   The program is listed belowl, to compile it just execute:

   gcc -arch ppc64 c-bigmem-test.c -o c-bigmem-test.exe

   "c-bigmem-test.exe" is the output - an executable file you may run.

The program is straightforward and it just tries to allocate more and more memory and it doesn't stop by itself (leave it or kill it!). On the screen you'll see the value of current memory taken. We tested it on the 64bit Linux /the memory status obtained from 64bit "top" matched the values printed out by our C program/ and when all system resources (physical memory + swap/hdd/ memory ) ran out, it was killed by the kernel which is correct.

Here is the code
--------
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#define ARRAY_SIZE 1000000

int main(){
char **bigbuf;
char buf [ARRAY_SIZE];
long long int i=0;

for(i=0;i<ARRAY_SIZE;i++){
buf[i]='A';
}

bigbuf=malloc(ARRAY_SIZE*sizeof(char *));

if(bigbuf==NULL){
printf("Main malloc failed!\n");
}

i=0;
while(++i){
char * str_tmp=malloc(ARRAY_SIZE*sizeof(char));

if(str_tmp==NULL){
printf("Internal malloc failed!\n");
}

bigbuf[i]=str_tmp;
strcpy(bigbuf[i], buf);
if(i==0) {printf("MB allocated: %lld\n",i);};
   }
   return 0;
}

--------