Petsc Error

Satish Balay balay at mcs.anl.gov
Tue Oct 9 13:09:19 CDT 2007


On Tue, 9 Oct 2007, Satish Balay wrote:

> On Tue, 9 Oct 2007, Berend van Wachem wrote:
> 
> > Hi,
> > 
> > I am using 32 bit linux (slackware) on a 64 bit opteron. Would using a 64 bit
> > linux distro help?
> 
> 32bit adressing => 4GB max. [both for the OS and a process].  But
> generally a single process allocate can allocate only 2GB or 3GB - not
> 4GB. [This is OS dependent - as the OS requires the process to use
> this remaining addressspace for other things].
> 
> 64bit linux will avoid this limitation.

Another note: Looks like your current 32bit OS is able to see all the
6GB of memory. This is possible with bigmem kernel - which uses 36
address bits to manage this.

http://en.wikipedia.org/wiki/Physical_Address_Extension

However each process still uses 32bit adressing - and its memory usage
limited to 2-3GB.

Satish




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