Originally posted by: Jiseok

PROGRAM memory_test

IMPLICIT NONE

Integer, PARAMETER :: n=12000

Complex*16, ALLOCATABLE :: a(:,:)

double precision, parameter :: double_cmplx_size=16 !byte

INTEGER :: i, j, alloc_error, dealloc_error

Double Precision :: memsize

memsize = double_cmplx_size*n*n/(1024*1024) !Mb

ALLOCATE(a(n,n), STAT=alloc_error)
If (alloc_error .ne. 0) Then
print *, 'alloc_error = ',alloc_error
print *, 'ERROR :: Allocate'

print *, 'size of the memory space needed = ', memsize, 'Mb'
!stop
End If
DEALLOCATE(a, stat=dealloc_error)
print *, 'dealloc_error = ',dealloc_error

END PROGRAM memory_test
================================================

Hi.

I have a array allocation test code above.
The size of the array would exceed 2Gb which is larger than the limit in 32-bit mode.
So I boot in 64 bit mode and tried to use -q64 option when compiling but it still shows 'Segmentation Fault'.

Anyone help would be appreciated.

Below shows the hardware info of my box

> prtconf

System Model: IBM,9114-275
Machine Serial Number: 104685C
Processor Type: PowerPC_POWER4
Number Of Processors: 2
Processor Clock Speed: 1452 MHz
CPU Type: 64-bit
Kernel Type: 64-bit
LPAR Info: 1 NULL
Memory Size: 8192 MB
Good Memory Size: 8192 MB
Platform Firmware level: 3F041029
Firmware Version: IBM,RG041029_d79e00_r
Console Login: enable
Auto Restart: true
Full Core: false

Originally posted by: Kosala

Hi,

Can you check what the "ulimit -a" says in the terminal you're executing this from.

Kosala

Originally posted by: Jiseok

> ulimit -a

core file size (blocks, -c) 1048575
data seg size (kbytes, -d) 131072
file size (blocks, -f) 1048575
max memory size (kbytes, -m) 32768
open files (-n) 2000
pipe size (512 bytes, -p) 64
stack size (kbytes, -s) 32768
cpu time (seconds, -t) unlimited
max user processes (-u) 128
virtual memory (kbytes, -v) unlimited

========================================================

Thank you for your reply.
I'm not that familiar with AIX and UNIX system.
If you can give some advices, it would be appreciated.

Originally posted by: Kosala

Hi,

You can override the default settings in the /etc/security/limits for your user. Try setting data, data_hard, stack, stack_hard to -1 for you user. You will need to re-login after these changes.

Kosala

Originally posted by: Jiseok

I appreciated for you help.
The problem is solved.
But I'm just wondering if it is safe to set data and stack size unlimited.
Also, just in case, can I set the max memory size, rss=-1 ?

Thank you again.

Originally posted by: jklotz

It's a common practice to put most limits (in perticular data, filesize, stack, cpu and rss) to -1. I never had problems because of this (the opposite is not true), and this is one of the first thing support line checks if you call them :)

Originally posted by: Kosala

Hi,

Generally I do this for WebSphere as the JVM consumes some crazy memory limits most of the times. But you have to make sure your application is not leaking memory, or the end result can be disastrous.

Kosala

Originally posted by: Jiseok

I really appreciate for your help.
Everything works fine for now :)