UNIX for Advanced & Expert Users

Hi,

I need to intentianlly use up memory. We have a product fix that that resolves an issue that only arrises when the system is under extreme load.

We have a SunOS, 5.8 test machine but have not been able to run enough data through to replicate the original issue and test the patch.


Any ideas?

Many thanks,

Neil

would you just be able to write a small c program to malloc() that much memory... would that work? im not too sure tho.

I agree with _R3d , something like this might work:

Code:

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>

#define SIZE 1024 * 1024
main( int argc, char *argv[] )
{

  while(1) {
    void *ptr;
    fork();
    ptr =  malloc( SIZE );
    printf("addr = %X\n" , ptr);
  }


  return 0;
}

Nathan -

that will flood the system until the process limit for the user or the system process limit is hit.
Are you sure you wanna do that?

No, actually I'm not sure. In fact, I wouldn't recommend doing this, but it _will_ use up memory. It's probably best to remove the fork() call, and maybe limit it ( don't use an infinite loop ).

Code:

  int i = 0;

  while(i < 200) {
    void *ptr;
    /* fork(); */
    ptr =  malloc( SIZE );
    printf("addr = %X\n" , ptr);
    i++;
  }

Even when I use an infinite loop (without the fork), I run out of memory pretty fast. ( Not sure why - my system should have a lot more available. I will assume there's a limit to how much memory can be allocated to a single process. )

addr = BFAC4008
addr = BFBC5008
addr = BFCC6008
addr = BFEA6008
addr = 0
addr = 0
addr = 0

Another way would be to build something huge with lots of simultaneous jobs.

Or mmap a few giant files....

rather than hack around consider going http://www.sourceforge.net
and look for stress test software. Or. I'm not a Sun person, but vendors often have this type of software available usually free. Check and see.