Fedora xen - Feb 2006 - Memory in xen kernel < physical memory

I have a system with 4 CPUs and 8GB RAM. I noticed that:
- When I boot up the machine with hypervisor kernel (fc5t3), I saw less
than 4GB RAM (/proc/meminfo). 
- When I boot up the machine with up kernel (fc5t3), I saw 4GB RAM
(/proc/meminfo). 
- When I boot up the machine with smp kernel (fc5t3), I saw 8GB RAM
(/proc/meminfo). 

Is that supposed to be for fc5t3?

Thanks,
Danny Trinh
CNE, MCSE, RHCE, LPIC1, A+
Engineer Tech/Senior Analyst
Linux OS Development
Dell Computer Corporation

On Wed, 2006-02-22 at 14:01 -0600, Danny_Trinh@Dell.com
wrote:
>  I have a system with 4 CPUs and 8GB RAM. I noticed that:
[snip]
> Is that supposed to be for fc5t3?
The Xen kernels don''t currently support PAE as it''s a bit of
an all or
nothing thing.  And enabling it would break using my laptop, thus being
less than good ;-)

Jeremy

I thought PAE was only for 32 bit machine? I''ve got a 64-bit opteron  
and also noticed that the FC5t3 hypervisor kernel doesn''t show all  
4GB of my RAM.

On Feb 22, 2006, at 12:12 PM, Jeremy Katz wrote:
> On Wed, 2006-02-22 at 14:01 -0600, Danny_Trinh@Dell.com wrote:
>>  I have a system with 4 CPUs and 8GB RAM. I noticed that:
> [snip]
>> Is that supposed to be for fc5t3?
>
> The Xen kernels don''t currently support PAE as it''s a bit
of an all or
> nothing thing.  And enabling it would break using my laptop, thus  
> being
> less than good ;-)
>
> Jeremy
>
> --
> Fedora-xen mailing list
> Fedora-xen@redhat.com
> https://www.redhat.com/mailman/listinfo/fedora-xen

On Wed, Feb 22, 2006 at 12:28:09PM -0800, Ben wrote:
> I thought PAE was only for 32 bit machine? I''ve got a 64-bit
opteron
> and also noticed that the FC5t3 hypervisor kernel doesn''t show all
> 4GB of my RAM.
A lot of Athlon64 boards only seem to support 3.5GB, like the old
Athlon MP boards.  I haven''t every been given a good reason why...

Steve
-- 
Steven Pritchard - K&S Pritchard Enterprises, Inc.
Email: steve@kspei.com             http://www.kspei.com/
Phone: (618)398-3000               Mobile: (618)567-7320

Well, I''m using the Epox 9NPA+ ultra board, and while I did have to  
turn on the oh-so-helpfully undocumented "s/w memory hole remapping"  
feature in the bios, doing so allowed my FC4 kernel to see all 4GB of  
memory.

On Feb 22, 2006, at 12:31 PM, Steven Pritchard wrote:
> On Wed, Feb 22, 2006 at 12:28:09PM -0800, Ben wrote:
>> I thought PAE was only for 32 bit machine? I''ve got a 64-bit
opteron
>> and also noticed that the FC5t3 hypervisor kernel doesn''t show
all
>> 4GB of my RAM.
>
> A lot of Athlon64 boards only seem to support 3.5GB, like the old
> Athlon MP boards.  I haven''t every been given a good reason why...
>
> Steve
> -- 
> Steven Pritchard - K&S Pritchard Enterprises, Inc.
> Email: steve@kspei.com             http://www.kspei.com/
> Phone: (618)398-3000               Mobile: (618)567-7320

Am Mittwoch, den 22.02.2006, 14:31 -0600 schrieb Steven
Pritchard:
> On Wed, Feb 22, 2006 at 12:28:09PM -0800, Ben wrote:
> > I thought PAE was only for 32 bit machine? I''ve got a 64-bit
opteron
> > and also noticed that the FC5t3 hypervisor kernel doesn''t
show all
> > 4GB of my RAM.
> 
> A lot of Athlon64 boards only seem to support 3.5GB,
Most with Socket 939 support 4 GByte afaics.
>  like the old
> Athlon MP boards.  I haven''t every been given a good reason why...
PCI-Address-Space just below 4 GByte needs around 0,25 up to round about
0,75 MByte normally (depending on PCI/PCIe/AGP devices you have
installed).

But most newer Mailboards support "Memory-Hoisting" (needs Rev. E
Athons
iirc). Enable it in the BIOS and use a 64-Bit-Operating-System to access
the complete 4**GByte of memory. 
-- 
Thorsten Leemhuis <fedora@leemhuis.info>