RE: large array, ia64, "segmentation fault"

RE: large array, ia64, "segmentation fault"

[Luck, Tony]

>Excuse me , In the REHL3 64bit platform ,how many can
>i increase the stack size? I mean the maximum size.

Use "ulimit -s {size}" ... you need to be "root" to increase
the limit.  The default seems to be 10MB:

 $ ulimit -s
 10240

-Tony

Re: large array, ia64, "segmentation fault"

[Joe Buck]

On Mon, Nov 29, 2004 at 10:53:03AM -0800, David Mosberger wrote:
> >>>>> On Sat, 27 Nov 2004 11:27:30 +0800 (CST), hx w <ye_hx_w@yahoo.com.cn> said:
> 
>   hx> Excuse me , In the REHL3 64bit platform ,how many can
>   hx> i increase the stack size? I mean the maximum size.
> 
> Depends on the shell.  With bash:
> 
> 	$ ulimit -s unlimited

Off topic, but risky advice has just been given.

This is not advisable, unless you want to risk waking the OOM-killer when
you accidentally write an infinite recursion.  At one time, "unlimited"
was the default in seveal GNU/Linux distros, and I ran into this problem
several times.

I would suggest choosing a limit that leaves room in your swap file in
case some program decides to use all the stack you allow it.

Re: large array, ia64, "segmentation fault"

[David Mosberger]

>>>>> On Sat, 27 Nov 2004 11:27:30 +0800 (CST), hx w <ye_hx_w@yahoo.com.cn> said:

  hx> Excuse me , In the REHL3 64bit platform ,how many can
  hx> i increase the stack size? I mean the maximum size.

Depends on the shell.  With bash:

	$ ulimit -s unlimited

  --david

RE: large array, ia64, "segmentation fault"

[Dave Korn]

> -----Original Message-----
> From: gcc-owner On Behalf Of Mike Stump
> Sent: 27 November 2004 21:50
> To: hx w
> Cc: gcc mail-list gcc; ia64; RHEL3 RHEL3
> Subject: Re: large array, ia64, "segmentation fault"
> 
> On Friday, November 26, 2004, at 07:27  PM, hx w wrote:
> > Excuse me , In the REHL3 64bit platform ,how many can
> > i increase the stack size?
> 
> See ulimit -a (ulimit -s).
> 

  We can even drag this (marginally) back OT for the gcc list by suggesting
he compile with the "-Wl,--stack=<some huge number>" flag :)



    cheers, 
      DaveK
-- 
Can't think of a witty .sigline today....
 

Re: large array, ia64, "segmentation fault"

[Mike Stump]

On Friday, November 26, 2004, at 07:27  PM, hx w wrote:
> Excuse me , In the REHL3 64bit platform ,how many can
> i increase the stack size?

See ulimit -a (ulimit -s).

Re: large array, ia64, "segmentation fault"

[hx w]

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Excuse me , In the REHL3 64bit platform ,how many can
i increase the stack size? I mean the maximum size.

Thanks!!


 --- Peter Barada <peter@the-baradas.com> µÄÕýÎÄ£º
> 
> >I compile a source , when N=100, everything is
> good;
> >but 
> >when i modify N=1000, i got the info: segmentation
> >fault. i am using icc 8.1.
> >
> >My sys info:
> >RHEL3-64bit update 2.
> >2.4.21-4.EL kernel
> >4-way Iatnium2 .
> >8G RAM.
> 
> You're trying to allocate a *large* amount of data
> off the stack int
> hte function main, probably enought to blow the
> limit on the stack
> size.  Look up the manual page for 'ulimit' and use
> that command (with
> the appropriate parameters) to increase the stack
> size limit
> 
> Your other choice is to move the definition oft
> A,B,C outside of main
> so they will be declared globally...
> 
> -- 
> Peter Barada
> peter@the-baradas.com
>  

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Re: large array, ia64, "segmentation fault"

[Peter Barada]

>I compile a source , when N=100, everything is good;
>but 
>when i modify N=1000, i got the info: segmentation
>fault. i am using icc 8.1.
>
>My sys info:
>RHEL3-64bit update 2.
>2.4.21-4.EL kernel
>4-way Iatnium2 .
>8G RAM.

You're trying to allocate a *large* amount of data off the stack int
hte function main, probably enought to blow the limit on the stack
size.  Look up the manual page for 'ulimit' and use that command (with
the appropriate parameters) to increase the stack size limit

Your other choice is to move the definition oft A,B,C outside of main
so they will be declared globally...

-- 
Peter Barada
peter@the-baradas.com

large array, ia64, "segmentation fault"

[hx w]

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I compile a source , when N=100, everything is good;
but 
when i modify N=1000, i got the info: segmentation
fault. i am using icc 8.1.

My sys info:
RHEL3-64bit update 2.
2.4.21-4.EL kernel
4-way Iatnium2 .
8G RAM.

So, does any one meet the same thing as me? What cause
the error info? And how cuold i do to resolve it?

Thanks !
£½£½£½£½£½£½£½£½£½£½£½£½£½£½£½£½£½£½£½£½£½£½£½£½£½£½£½£½
#include <stdio.h>
#include <sys/time.h>
#include <stdlib.h>

#define  N 1000
void Input(double A[N][N], double B[N][N]);
void MultiplyS(double A[][N], double B[][N], double
C[][N]);

int main()
{
    int i,j,k;
    double A[N][N],B[N][N],C[N][N];
    struct timeval start_time,end_time;
    double  elapsed_time;

    gettimeofday(&start_time,NULL);
    Input(A,B);
    MultiplyS(A,B,C);
    gettimeofday(&end_time,NULL);
   
elapsed_time=1000000*(end_time.tv_sec-start_time.tv_sec)+
end_time.tv_usec-start_time.tv_usec;
    elapsed_time/=1000000;

    printf("Used Time:%f seconds\n",elapsed_time);

    return 0;
}


void Input(double A[N][N],double B[N][N])
{
   int i,j;
   for( i=0; i<N; i++)
     for( j=0; j<N; j++)
     {
       A[i][j] = 1;
       B[i][j] = 0.8;
     }
  }

void MultiplyS(double A[][N], double B[][N], double
C[][N])
{
   int i,j,k;
   for(i=0; i<N; i++)
      for( j=0; j<N; j++)
      {
        C[i][j] = 0;
        for( k=0; k<N; k++)
           C[i][j]+= (A[i][k]* B[k][j]);
      }
}
£½£½£½£½£½£½£½£½£½£½£½£½£½£½£½£½£½£½£½£½£½£½£½£½£½£½£½£½

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