Re: [Xen-users] 32bit vs 64bit memory usage question

["Jamie Burns" <fantasticjamieburns@xxxxxxxxxxx>]

Hi,

Well, I didn't ask if it was faster......

And no it is not necessarily slower, x86-64 architecture has various other 
improvements, in particular the number of available CPU registers.
Jamie.

----- Original Message ----- 
From: "Tom Miller" <madprogextrodinr@xxxxxxxxx>
To: <xen-users@xxxxxxxxxxxxxxxxxxx>
Sent: Monday, February 05, 2007 3:00 PM
Subject: Re: [Xen-users] 32bit vs 64bit memory usage question


> Jamie Burns wrote:
> > Hello,
> >
> > I recently installed a minimal 32bit version of Debian Etch, and then 
> > also installed Xen from Debian's package repository.
> > When Xen booted up, memory usage was just below 40MB (typical for such a 
> > debian install).
> > Then I decided to do the exact same install, but using the 64bit version 
> > of Debian Etch and Xen.
> > This time when Xen booted up, memory usage was just over 90MB - at least 
> > double that of the 32bit version.
> > Can anybody explain this to me? Why 64bit XEN would use double the 
> > memory?
> > If I try 32bit vs 64bit debian without using XEN, then memory use about 
> > 30MB with each - no doubling.
> > Jamie Burns.
> >
> > _______________________________________________
> > Xen-users mailing list
> > Xen-users@xxxxxxxxxxxxxxxxxxx
> > http://lists.xensource.com/xen-users
> 64 bit pointers and 64 bit memory address slots are twice as big as
> corresponding 32 bit ones.   So unless you have 4 GB of memory or more,
> using 64bit software is actually slower for the system, not faster.
>
>
> _______________________________________________
> Xen-users mailing list
> Xen-users@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-users
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