Re: Only 3.6gb of 64gb RAM recognized by 64bit squeeze

[Arnt Karlsen <arnt@c2i.net>]

On Wed, 9 May 2012 13:01:25 +0200, Seyyed wrote in message 
<[🔎] CAKJMjaJM8PnwFpknfZ+1C62rhFR=SzdVjUkuLc_pa3c_z+wGYg@mail.gmail.com>:

> On Wed, May 9, 2012 at 12:32 PM, Arnt Karlsen <arnt@c2i.net> wrote:
> 
> > On Wed, 9 May 2012 11:19:10 +0200, Seyyed wrote in message
> > <[🔎] CAKJMja+mrpWmo8uhakjGfwsuk3W0=+A6LMBhFvXKKFCtErf6_w@mail.gmail.com>:
> >
> > > Hello,
> > >
> > > Before anybody starts arguing that I don't have 64-bit, this is
> > > uname -r and uname -m:
> > > root@n03:~# uname -r
> > > 2.6.32-3-amd64
> > > root@n03:~# uname -m
> > > x86_64
> > >
> > > As the subject suggest I have a box that does not utilize the
> > > available RAM installed. I noticed that only 3.6gb RAM was
> > > recognized when I got segmentation faults during a simulation.
> > > The funny thing is that when I remove dims so that only 48gb RAM
> > > is available then it works fine, I did a 'lshw -C memory' and it
> > > shows all the dims at the correct spot (the output is attached).
> > > BIOS and memtest show and successfully test all 64gb.
> > >
> >
> > ..post a one core snip of your /proc/cpuinfo, I'm wondering
> > if you've hit some 36 bit address space ceiling.  I have ...
> > root@celsius:~# cat /proc/cpuinfo
> > processor       : 1
> > vendor_id       : GenuineIntel
> > cpu family      : 6
> > model           : 15
> > model name      : Intel(R) Core(TM)2 CPU         T7200  @ 2.00GHz
> > ...
> > bogomips        : 3989.93
> > clflush size    : 64
> > cache_alignment : 64
> > address sizes   : 36 bits physical, 48 bits virtual
> > power management:
> >
> > ...and:
> > root@celsius:~# qalc 2^36bytes to GiBytes
> > (2^36) * byte = 64 gibibytes
> >
> 
> Here you go:
> processor       : 31
> vendor_id       : AuthenticAMD
> cpu family      : 21
> model           : 1
> model name      : AMD Opteron(TM) Processor 6274
...
> address sizes   : 48 bits physical, 48 bits virtual

..ok, your cpus have 48 bit address space, is there anything 
else that could force you into a 36 bit straitjacket? 

..what happens if you remove 2 ram sticks?


-- 
..med vennlig hilsen = with Kind Regards from Arnt Karlsen
...with a number of polar bear hunters in his ancestry...
  Scenarios always come in sets of three: 
  best case, worst case, and just in case.